CONDITION ASSESSMENT STRATEGIES

03-CTS-20CO CONDITION ASSESSMENT STRATEGIES AND PROTOCOLS FOR WATER AND WASTEWATER UTILITY ASSETS by: David Marlow, CSIRO Simon Heart, MWH Stewart Burn, CSIRO Antony Urquhart, MWH Scott Gould, CSIRO Max Anderson, MWH Steve Cook, CSIRO Michael Ambrose, CSIRO Belinda Madin, MWH Andrew Fitzgerald, MWH 2007 Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets ES-i

ACKNOWLEDGEMENTS The researchers would like to acknowledge the kind assistance of all those who contributed to this project, including: Report Preparation Principal Investigators: Antony Urquhart, Dip.Bus, CPEng., MWH Stewart Burn, CSIRO Project Team: David Marlow, Ph.D., CSIRO Simon Heart, M.S., PE, MWH Scott Gould, BEng, BBus Admin., CSIRO Max Anderson, CPEng., MWH Steve Cook, M.S., CSIRO Michael Ambrose, CSIRO Belinda Madin, MWH Andrew Fitzgerald, MWH Project Steering Committee Stephen Allbee, United States Environmental Protection Agency Greg Cawston, Sydney Water John Colbert, Massachusetts Water Resources Authority Wayne Dillard, Burns & McDonnell John W. Fortin, Asset Management Consultant, Cohasset, MA Susan Karlins, City of Houston Charles Murray, Fairfax County Water Authority Jon Schellpfeffer, Madison Metropolitan Sewerage Department Jennifer Warner, AWWA Research Foundation Water Environment Research Foundation Staff Director of Research: Daniel M. Wolstring, Ph.D. Program Manager: Roy Ramani, Ph.D. ii

A Water Environmental Research Foundation (WERF) sponsored workshop held in March 2002 identified that there were no standardized guidelines for conducting condition assessments, and that there is a need for protocols to help utilities better understand asset condition and performance. A research project jointly funded by WERF, the American Water Works Association Research Foundation (AwwaRF) and the United States Environmental Protection Agency (U.S. EPA) was developed to fill this gap. This report presents the findings of this research, focusing on the following objectives: 1) documenting the broad range of available asset assessment tools and techniques, and 2) providing guidance on how to incorporate condition assessment strategies into a utility s asset management philosophy. The important links between accepted and emerging principles of asset management and approaches to condition assessment are discussed. Generic approaches to assessment program design and tool selection are offered for both strategic asset management and day-to-day maintenance purposes, which can be applied across a range of asset types. The information presented draws upon a range of case studies undertaken with utilities in the United States, Australia, New Zealand and the United Kingdom. A tool selection procedure is presented that uses an exclusion process in which tools and techniques are excluded from further consideration based on criteria relating to technical feasibility, technical suitability and utility technical capacity. Remaining options must then be evaluated through economic or financial analysis so that final selection is made with regard to available resources, the cost-benefits accrued and utility affordability issues. The report outlines approaches that can be taken in this analysis. The report also provides descriptions and reviews of 85 individual condition assessment tools and techniques used in the water and wastewater industry, including a discussion of principles, applications, practical considerations, advantages and limitations. A prototype expert system (ES) was developed to investigate the use of this technology and also to facilitate the production of tool selection tables for inclusion in the final report. While these tables are a pragmatic paper-based solution, it is recommended that the prototype expert system be further developed to provide the sector with 1) a more flexible selection tool, and 2) a framework for future updating, maintaining and distributing refinements of the tool reviews and information. Benefits Delivered by this Research Project ABSTRACT AND BENEFITS Provides a step-wise approach for developing a cost-effective condition and performance assessment program for water and wastewater utilities. Provides guidance for integrating condition and performance assessment programs into a utility s overall asset management framework. Recommends criteria for selecting assessment tools and techniques. Describes and reviews available condition assessment tools and techniques used in the water and wastewater industry, including principles, applications, practical considerations, advantages and limitations. Provides a prototype expert system to facilitate the selection of condition assessment tools and enable updating and refinements of tool selection in the future. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets iii

Includes case study examples of applications of condition and performance assessment techniques at leading water and wastewater utilities throughout the world. Keywords: Condition assessment, asset condition, asset performance, asset management, tool selection, utility infrastructure, risk management, case studies, assessment tools iv

TABLE OF CONTENTS Acknowledgements...ii Abstract, Benefits and Key Words... iii List of Tables...vii List of Figures... viii List of Acronyms...ix Executive Summary... ES-1 Strategic Asset Management Focus for Utility Planning Managers... ES-1 Maintenance Management Focus for Engineering and Maintenance Managers. ES-3 Project Recommendations... ES-7 Chapter 1 Introduction... 1-1 1.1 Introduction... 1-2 1.2 Project Delivery... 1-3 1.3 Linkage to Related Research... 1-3 1.4 Report Structure... 1-4 1.5 How to Use this Report... 1-5 1.6 Document Road Map... 1-6 Chapter 2 Condition Assessment as a Strategic Asset Management Tool... 2-1 2.1 Introduction... 2-2 2.2 Strategic Asset Management... 2-3 2.3 Condition Assessment as an Input to Strategic Asset Management... 2-11 2.4 When to Undertake Condition Assessment... 2-14 Chapter 3 Developing an Assessment Program... 3-1 3.1 Introduction... 3-2 3.2 The Role of Risk in the Design of an Assessment Program... 3-2 3.3 Outputs from a Condition Assessment Program... 3-4 3.4 Designing a Condition Assessment Program... 3-15 3.5 Additional Implementation Issues... 3-24 3.6 Documentation and Reporting... 3-27 Chapter 4 Justifying a Condition and Performance Assessment Program... 4-1 4.1 Introduction... 4-2 4.2 Key Benefits of Condition and Performance Assessment Programs... 4-2 Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets v

4.3 Key Cost Elements for Effective Condition Assessment Programs... 4-4 4.4 Economic Justification... 4-6 4.5 Other Approaches to Justification... 4-7 4.6 Optimizing Cost and Benefits Associated with Assessment Programs... 4-7 Chapter 5 Condition Assessment as a Maintenance Management Tool... 5-1 5.1 Introduction... 5-2 5.2 Approaches to Maintenance... 5-3 5.3 The Role of Condition Monitoring in Proactive Maintenance... 5-4 5.4 Risk-based Assessment Procedures... 5-6 5.5 A Generic Approach to Specifying Condition Monitoring Tasks... 5-12 5.1 Development of a Condition Monitoring Program... 5-14 Chapter 6 Selecting Tools and Techniques... 6-1 6.1 Introduction... 6-2 6.2 A Protocol for Selecting Condition Assessment Tools... 6-2 6.3 Exclusion Criteria... 6-4 6.4 Application of Exclusion Protocol... 6-5 6.5 Development of a Prototype Expert System (ES)... 6-8 6.6 The Impact of Risk and Cost on Tool Selection... 6-8 6.7 An Iterative Approach to Asset Assessments... 6-10 Chapter 7 Available Tools and Techniques... 7-1 7.1 Introduction... 7-2 7.2 Representation of the Asset Stock... 7-2 7.3 Mapping Tools onto the Asset Stock... 7-4 7.4 Tool Selection Process... 7-7 Chapter 8 Case Study Details... 8-1 8.1 Introduction... 8-2 8.2 Purpose of the Case Studies... 8-2 8.3 Case Study 1: Scottish Water s Program of Treatment Plant Assessments. 8-3 8.4 Case Study 2: Scottish Water s Approach to Grading of Water Mains... 8-7 8.5 Case Study 3: Water Corporation s ACA Program... 8-10 8.6 Case Study 4: Water Corp s Assessment Approach for Water Tanks... 8-13 8.7 Case Study 5: Water Corp s Investigation of a Trunk Main Failure.... 8-15 vi

8.8 Case Study 6: Water Care Services Limited Assessments of Sewerage Assets..... 8-19 8.9 Case Study 7: Water Care s Assessments of A Critical Sewer... 8-21 8.10 Case Study 8: Melbourne Water s Assessments of Steel Tanks... 8-24 8.11 Case Study 9: Sydney Water s Management of M&E Assets... 8-28 8.12 Case Study 10: City of Bellevue s Risk-Based Approaches... 8-31 8.13 Case Study 11: Massachusetts Water Resources Authority RCM Program....... 8-33 8.14 Case Study 12: MWRA s Strategies for Pipe Network Management... 8-35 8.15 Case Study 13: CSIRO s Assessment of a Cast Iron Transmission Main.. 8-37 8.16 Case Study 14: CSIRO s Assessment of an Asbestos Cement Force Main. 8-40 Appendix A Utility Objectives and Related KPIs... A-1 Appendix B Individual Drivers for Assessment...B-1 Appendix C Condition and Performance Assessment Criteria... C-1 Appendix D A Generic Condition Assessment Form for Mechanical and Electrical Equipment... D-1 Appendix E Development of a Prototype Expert System...1 Appendix F Review of Condition Assessment Tools and Techniques..F-1 Glossary of Terms... G-Error! Bookmark not defined. Reference List...R-Error! Bookmark not defined. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets vii

LIST OF TABLES Table 2-1. Approaches to Asset Management Adopted.... 2-7 Table 2-2. The Impact of Scale on Asset Management Resources (after Shaw 2001). 2-11 Table 2-3. Strategic Objectives, Related KPIs and Approach to Assessment... 2-17 Table 2-4. Drivers for Undertaking Condition and Performance Assessment.... 2-20 Table 3-1. Condition and Performance Assessment Criteria... 3-11 Table 3-2. Ofwat PR99 Information Sewer Grading System (Ofwat, 1998).... 3-12 Table 3-3. Approaches to Assessing Different Asset Types....25 Table 4-1. Benefits of Undertaking Condition/Performance Assessment... 4-3 Table 4-2. Cost Elements... 4-4 Table 5.1. Estimated Projection of the Vibration Monitoring Cost Avoidance Benefits...... 5-18 Table 5-2. Ten-Year Projected Condition Monitoring Costs.... 5-19 Table 6-1. Exclusion Criteria for Inspection and Survey Tools/Techniques... 6-6 Table 6-2. Exclusion Criteria for Asset Management and Assessment Tools/Techniques..... 6-7 Table 6-3. Utility Criteria that Influence the Choice of Tools/Techniques... 6-7 Table 6-4. Sliding Scale of Assessment Standards... 6-11 Table 7-1. Service Area: Water Supply... 7-3 Table 7-2. Service Area: Wastewater Collection and Disposal... 7-4 Table 7-3. Hierarchical Representations for Complex Assets... 7-5 Table 7-4. Hierarchical Representations for Complex Assets... 7-6 Table 7-5. Hierarchical Representations for Complex Assets... 7-6 Table 7-6. Tool and Technique Selection Tables.... 7-8 Table 8-1. Guidance for the Grading of Condition... 8-14 Table 8-2. Weighted Scoring for Asset Components.... 8-27 Table 8-3. Inspection Tools and Techniques Used by SWC... 8-30 viii

LIST OF FIGURES Figure ES-1: A 10-Step Approach to Specifying a Condition Assessment Program...ES-3 Figure ES-2: A Generic Approach to Specifying Condition Monitoring Techniques..ES-4 Figure 2-1. Business Drivers and Utility Capabilities... 2-2 Figure 2-2. The PAS 55 Physical Asset Management Framework.... 2-5 Figure 2-3. Determining Data Requirements through Information Needs... 2-6 Figure 2-4. The Asset Management Cycle.... 2-8 Figure 2-5. The Relationship between Asset Condition, Age and Failure Probability. 2-12 Figure 2-6. The Process of Developing a Performance Management System.... 2-15 Figure 2-7. The Role of Condition Assessment in Utility Decision Making.... 2-18 Figure 2-8. Condition Assessment Undertaken in Response to Individual Drivers... 2-19 Figure 3-2. A 10-Step Approach to Specifying a Condition Assessment Program.... 3-18 Figure 5-1. Business Drivers and Utility Capabilities... 5-2 Figure 5-2. The Failure Process as Described by the P-F Curve... 5-5 Figure 5-3. A Generic Approach to Specifying Condition Monitoring Techniques.... 5-13 Table 5-3. Estimated Projection of the Oil Analysis Cost Avoidance Benefits.... 5-21 Figure 6-1. Process Flowchart for Developing Condition Monitoring Programs.... 6-3 Figure 6-2. Approach to Selecting Condition Assessment Tools... 6-4 Figure 6-3. Iterative use of Condition and Performance Assessments... 6-12 Figure 8-1. Comparison of Assets in Condition Grade 4/5 by Asset Value... 8-5 Figure 8-2. Schematic of Water Corporation s ACA Process... 8-11 Figure 8-3. Typical Failure Mode for Cast Iron Pipe.... 8-37 Figure 8-4. Weibull Plot for Corrosion Data... 8-38 Figure 8-5. Expected Failure Rate per Year.... 8-39 Figure 8-6. Determining Residual Strength of the Cores.... 8-41 Figure 8-7. Weibull Plot for Deterioration Rates.... 8-41 Figure 8-8. Distribution of Remaining Lives.... 8-42 Figure 8-9. Life Time Distribution Along the Pipeline.... 8-42 Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets ix

LIST OF ACRONYMS & ABBREVIATIONS 3D AC ACA AwwaRF BBEM C&B CARD CARE-S CCTV CG CI CMMS CMOM CSO DCVG DITP DSS DT ECARD ES FMEA FMECA FTEs GIS GPR GUI ICA ICGs IE I&I INMS Km KPI LPR m mm M&E mgd MM MO MWRA NASSCO NRC NDT Three Dimensional Asbestos Cement Asset Condition Assessment American Water Works Association Research Foundation Broadband Electro Magnetic Civil and Building Condition Assessment and Risk Determination Computer Aided Rehabilitation of Sewer And Storm Water Networks Closed Circuit Television Condition Grade Cast Iron Computerized Maintenance Management System Capacity assurance, Management, Operation and Maintenance Combined Sewer Overflow Direct Current Voltage Gradient Dear Island Treatment Plant Decision Support System Destructive Testing Electrical Condition Assessment and Risk Determination Expert System Failure Modes and Effects Analysis Failure Modes, Effect and Criticality Analysis Full Time Equivalents Geographic Information System Ground Penetrating Radar Graphical User Interface Instrumentation, Control and Automation Internal Condition Grades Impact Echo Infiltration and Inflow Integrated Network Management System Kilometers Key Performance Indicator Linear Polarization Resistance Meters Millimeter Mechanical and Electrical Million Gallons Per Day Millimeter Maintenance Optimization Massachusetts Water Resources Authority National Association of Sewer Service Companies National Research Council of Canada Non-Destructive Testing x

O&M Ofgem Ofwat PARMS PDF PE PG PM PMO Q&S QC RBI RCM RPN ROI SAM SASW SCRAPS SIMPLE SRM SSET STPs SPG SWC TEV TFI UID U.S. EPA Water Care WERF WIC WRc WQ Operations and Maintenance Office of Gas and Electricity Markets Office of Water Services Pipeline Asset and Risk Management System Probability Density Function Polyethylene Performance Grade Preventive Maintenance Preventative Maintenance Optimization Quality and Standards Quality Control Risk-Based Inspection Reliability Centered Maintenance Risk Priority Number Return on Investment Strategic Asset Management Spectral Analysis of Surface Wave Sewer Cataloguing, Retrieval and Prioritization System Sustainable Infrastructure Management Program Learning Environment Sewer Rehabilitation Manual Sewer Scanner and Evaluation Technology Sewage Treatment Plants Structural Performance Grade Sydney Water Corporation Transient Earth Voltage Transverse Flux Inspection Unacceptable Intermittent Discharge United States Environmental Protection Agency Water Care Services Limited Water Environment Research Foundation Water Industry Commissioner Water Research Centre Water Quality Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets xi

EXECUTIVE SUMMARY Water and wastewater utilities in developed countries are faced with the challenge of how to most cost effectively manage a large investment in physical assets while providing safe and reliable services to their customers. A strategic asset management (SAM) approach can help utilities meet this challenge. A key element of SAM is the assessment of asset condition and performance. The objective of this research was to provide water and wastewater utilities with guidance and information on how to effectively use condition assessment tools and techniques to improve both the long-term planning and day-to-day management of assets. The research was undertaken in two phases. Phase 1 of the project involved a web-based survey and a review of the literature and other information sources. Phase 2 was undertaken as a refinement stage, where concepts developed in Phase 1 were developed further, drawing on the knowledge from a range of case study partners and professionals working within the sector. To this end, various case studies were undertaken during Phase 2 to gain input from a range of utilities and industry practitioners across the globe. This report is structured for two distinct audiences: Utility planning managers who are seeking to understand how to embark upon costeffective condition and performance assessment programs, in order to support long-term planning decisions. Engineering or maintenance managers that are seeking to identify and understand the advantages and disadvantages of various available tools and techniques for measuring the condition and performance of utility assets, in order to support daily maintenance and operation of assets. The remainder of this Executive Summary, and the following report, is structured to assist these two audiences. Strategic Asset Management Focus for Utility Planning Managers In the water and wastewater utility sectors, there has been an evolution of asset management philosophies from a focus on managing assets to condition and performance targets, to a focus on achieving service level and business risk targets. Because of this, more recent asset management philosophies do not focus directly on managing asset condition as an output but instead seek to deliver appropriate service levels to customers and minimize risk in the most cost-effective manner. However, there remains a very strong and direct relationship between the condition of assets, their likelihood of failure, and subsequently, service reliability and risk. To provide a sustainable service, utilities need to understand the way in which asset condition changes with time, and how this relates to the provision of services to customers. Condition assessment is an important element in enhancing this understanding at both asset-specific and system-wide levels. Why Undertake Condition and Performance Assessments? Condition and performance monitoring are typically undertaken for the management of individual assets, but can also be undertaken in order to inform SAM decision making. In this latter case, the utility will ideally undertake high-level performance monitoring (through appropriate key performance indicators) to drive SAM decision making, and only undertake asset-level condition and performance assessments where there is a need to fill a specific gap in Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets ES-1

the information arising from this performance monitoring. Asset-level condition and performance assessment for SAM are also often undertaken because some form of internal or external (e.g., regulatory) driver is imposed on the utility that necessitates these specific assessments. A key purpose of condition assessment is to establish the current condition of assets as a means of prioritizing and forecasting maintenance and rehabilitation efforts. Some assets are, however, more important than others and should receive proportionally more attention. A standard way to characterize the importance of an asset is to evaluate the risk of it failing. Risk is an important consideration in asset management and the design of cost-effective condition assessment programs. Condition assessment can be used to understand the level of asset deterioration and the impact it has on the probability of asset failure, which is one component of risk; the other component being the consequences of asset failure. The utility can then attempt to either reduce the probability of failure through some operational or capital intervention, or accept the level of risk associated with the asset s condition. When undertaking condition assessments, inspection data are collected using tools that provide information on such things as the presence of defects and their severity. However, even when a defect, such as a crack or corrosion is identified, the question still remains as to the significance of the findings. Data collected during inspection of assets must be interpreted through appropriate analysis to give an assessment of condition in terms of the operating demands placed on the asset. Assessment Program Design A generic approach to designing a program of assessments has been developed that can be applied within a range of asset management sophistications, using different approaches to condition assessment across a range of asset types. Within this generic approach, the integration of a condition and performance assessment program within asset management is achieved through 10 steps, which are shown in Figure ES-1. Assessment Program Cost and Benefit Considerations Condition and performance assessment programs provide many benefits, but can also be expensive and time-consuming activities. Ideally, the expenditure on assessment programs should be balanced against the anticipated benefits. This requires that the cost and benefits associated with the programs be identified and evaluated in some way. The costs associated with condition and performance programs can vary greatly depending on a utility s current state of program and tool development, and the current training levels of its staff. Program-specific costs will also vary depending on the frequency of asset inspection prescribed and the number of assets to be inspected. While benefits are typically more difficult to quantify than costs, several methods are outlined, including: improved operations and maintenance efficiencies; catastrophic failure avoidance; and improved service levels and program efficiencies. It was noted during the research that many of the utilities contacted did not carry out explicit cost-benefit analyses to justify their assessment programs. Assessments were instead commonly undertaken within the context of available budgets, and a justification process driven more by affordability and cost-effectiveness issues than explicit consideration of cost-benefits. ES-2

Figure ES-1: A 10-Step Approach to Specifying a Condition Assessment Program. Maintenance Management Focus for Engineering and Maintenance Managers Effective maintenance practices help to preserve asset capabilities and in turn underpin the delivery of service on a daily basis. In general, routine maintenance tasks should be carried out in line with equipment manufacturer s recommendations and/or industry standards, as appropriate, since this prolongs the life of an asset. However, the level of maintenance applied over and above these routine tasks should depend on the importance of an asset to the utility s business objectives and thus the role the asset plays in service delivery: For assets of low value and/or where the impact of failure is not significant, additional maintenance is not cost-effective and utilities should adopt a reactive run-to-failure strategy. At a certain level of asset importance, it becomes desirable to use proactive maintenance strategies, including condition assessment or monitoring, to manage the probability of failure. Protocols for Assessing Condition and Performance of Water and Wastewater Assets ES-3

Proactive Maintenance Strategies A key requirement for the implementation of a proactive maintenance strategy is the ability to anticipate when a failure will occur. Inspection of condition and monitoring of asset performance, either by manual or automated means, plays a significant role in this. Development of an effective inspection program is centered on knowing when, where and how to inspect. If a utility finds evidence that an asset is in a state that will eventually lead to a functional failure, it may be possible to take action to prevent it from failing completely and/or avoid/mitigate the failure consequences. Many assets have failure modes that give some sort of warning that a problem is about to occur. Inspection tasks designed to detect potential failure are often referred to as condition-monitoring tasks. Condition-monitoring task intervals must be determined based on the time between the point at which the onset of the failure process becomes detectable, and the point at which a functional failure occurs (referred to as the P-F interval). If a condition-monitoring task is performed on intervals longer than the P-F interval, the potential failure may not be detected in time to prevent failure. On the other hand, if the condition-monitoring task is performed too frequently compared to the P-F interval, resources are wasted. Specifying Appropriate Condition Monitoring Tasks A number of approaches are available to help utilities develop an effective maintenance strategy. These methods are based on the generation and comparison of relative risk for different maintenance strategies, and include Reliability Centered Maintenance (RCM) and Risk Based Inspection. A generic approach to specifying condition monitoring tasks is shown in Figure ES- 2. Figure ES-2: A Generic Approach to Specifying Condition Monitoring Techniques. ES-4

When considering a change to any maintenance activity, the key challenge faced by a maintenance manager is to consider what level of activity is appropriate. In practice, this often reduces to the need to determine what percentage of the maintenance budget and resources can or should be dedicated to an activity such as condition monitoring. Various issues need to be considered, including what condition monitoring technologies to use, the increase in maintenance tasks anticipated (especially in the short term before the benefits of the improved maintenance regime start to be observed), resources and equipment required and/or available, and the anticipated cost and benefits of the program. Selecting Condition Assessment Tools and Techniques A key goal of this research was to provide a framework that would assist utilities in the selection and use of condition assessment tools. Selection tables have been developed to facilitate this and are based on summaries and detailed write-ups of the available inspection, survey and condition assessment tools and techniques. The selection process is summarized as: 1. Determine technical feasibility - identify the types of tools that are appropriate to the condition assessment application under consideration. 2. Review the tool summary information - identify applicable techniques. 3. Detailed review of potential tools examine detailed tool descriptions to determine most appropriate candidate tools. 4. For viable options, undertake cost-benefit analysis give due consideration to the accuracy of the tool, the level of asset risk, and the available budgets. Selection criteria have been developed to guide the selection of tools and techniques. Where relevant information could be found, the attributes relating to the exclusion criteria have been evaluated for each of the tools and techniques identified and reviewed in this project. These attributes therefore summarize the application and use of the tools, and provide the information necessary to identify the range of tools and techniques that are applicable to the condition assessment application under consideration. Initial work has also been undertaken to develop a prototype expert system (ES) to facilitate this tool selection process, and it is recommended that this work be completed as part of a follow-on project. Cost Effective Condition Monitoring Understanding the risk associated with an asset is critical to determining the appropriate proactive level of attention to give that asset. A direct extension of risk-based arguments is that the more important the asset is (the higher the consequences of failure), the more expense can be justified in assessments undertaken to ensure the asset does not fail. However, to minimize costs, inexpensive tools should still be used where possible. As such, the following can be stated: Inexpensive screening tools and approaches should be used routinely. The results of the screening approach may dictate that there is a need for additional information and/or accuracy. This may require the use of more sophisticated/accurate assessment or inspection tools. Additional expense should be considered only when justified in terms of risk costs avoided or benefits accrued. Protocols for Assessing Condition and Performance of Water and Wastewater Assets ES-5

An iterative approach to the use of tools is therefore suggested, where increasing levels of sophistication are used that build on the results of previous tools and assessments. In this approach, tools are initially selected that perform a screening function; for example, to identify the early signs of deterioration. More detailed inspection and analysis can then be used to investigate the asset condition further, if and when justified. ES-6

PROJECT RECOMMENDATIONS A research project of this scope and depth inevitably leaves some issues unresolved and identifies areas for future research. As such, the project team recommends the following actions for future consideration by the project sponsors: 1. The prototype expert system for tool and technique selection be further developed into a finished software tool, and that this tool be designed to allow the information contained within it to be kept current through an effective update mechanism. 2. Work be undertaken to integrate effectively the outputs of this research and the expert system into the Sustainable Infrastructure Management Program Learning Environment (SIMPLE) web site. If possible, this should include a facility for utilities to provide representative costbenefit data for condition and performance assessment programs they undertake. 3. A drinking-water version of the SIMPLE web site be produced for the benefit of the drinking water sector. 4. Further research is undertaken into the use of condition and performance assessment in the estimation of asset remaining life across all key drinking and wastewater asset types. 5. Further research and development of non-destructive assessment techniques be considered, especially research aimed at developing inspection techniques for buried pipe assets such that appropriate condition information is gathered while the assets remain in service. (See also, Section 5 of USEPA, 2005, which calls for this type of research). Protocols for Assessing Condition and Performance of Water and Wastewater Assets ES-7

Chapter Highlights CHAPTER 1.0 INTRODUCTION This report represents the culmination of a two-year research project jointly sponsored by the Water Environment Research Foundation (WERF), the American Water Works Association Research Foundation (AwwaRF) and the United States Environmental Protection Agency (U.S. EPA). Utilities throughout the world are faced with the challenge of how best to manage their existing asset stock to provide satisfactory customer service with limited funds. A key element of effective asset management is a cost-effective program for assessing the condition and performance of existing assets. However: No standardized guidelines or protocols currently exist for utilities to understand how to develop and implement condition assessment programs and to show how these programs should fit into an overall asset management program. No single resource currently exists for utilities to identify and understand the tools and techniques that are available to assess the condition and performance of their assets. This research effort has been undertaken as an initial effort to fill these two important voids. In doing so, this report attempts to reach two audiences: The utility planning managers who are seeking to understand how to embark upon cost-effective condition and performance assessment programs and how these efforts should fit within an overall asset management approach. This audience will be most interested in Chapters 1.0-4.0 and the case studies presented in Chapter 8.0. The utility field engineering, operations and maintenance managers who are seeking to identify and understand the advantages and disadvantages of various available tools and techniques for measuring the condition and performance of utility assets. This audience will be most interested in Chapters 5.0-7.0 and the case studies presented in Chapter 8.0. To facilitate the use of the report further, an attempt has been made to anticipate questions a user may wish to answer and to provide an indication of where in the document related information can be found. These questions are presented as a document road map within this chapter. While this report focuses on condition assessment tools and techniques more so than performance assessment, the subject of performance assessment is recognized (and covered to a lesser extent) as an important means of understanding asset condition. Protocols for Assessing Condition and Performance of Water and Wastewater Assets 1-1

1.1 Introduction Recent infrastructure studies undertaken in the United Kingdom, Australia and the United States have shown a common cause for concern there is widespread deterioration of critical water and wastewater infrastructure assets, with significant shortfalls in the renewal/replacement investment required to ensure that water and wastewater utilities can deliver sustainable services to their communities. For example, in the United States, the American Society of Civil Engineers (ASCE, 2001) released a report that assigned letter grades to 12 categories of public works; the overall average was a grade of D+, considered to be a poor rating, and only one grade higher than inadequate/ failing. The long-term cost implications of continuing with a poorly structured replacement/renewal regime could be dramatic. For example, the United States based Water Infrastructure Network estimated that the gap between spending levels and the investment required to meet the United States national environmental and public health priorities embodied in its Clean Water Act and Safe Drinking Water Act will reach US$23 billion a year over the next 20 years (Water Infrastructure Network 2000). Similarly, the American Water Works Association estimated that US$250 billion over 30 years might be required nationwide for the replacement of just water distribution pipes and their associated valves and fittings (AWWA, 2001). This situation is, to a greater or lesser extent, common to the water sectors of many countries, and has largely come about through assets reaching the end of their life expectancy without being replaced. This in turn can be related to the adoption of management practices with a short-term focus, which has led to the deferral of investment required for asset renewals. For example, in the United States, there has been a tendency to focus on 12-18 month funding cycles and project deliverables due to the nature of annual government budgets. This funding trend, combined with two to four year election cycles, has created an atmosphere that encourages short-term decision making on infrastructure matters, rather than a long-term view (Rast, 2003). The challenge for many water utilities today is to determine how best to manage their asset stocks with limited replacement funds, while maintaining a satisfactory level of service in the long term. Given this challenge, WERF held a workshop in March 2002, entitled Research Priorities for Successful Asset Management. The workshop addressed asset management issues across public water and wastewater utilities and recommended a research agenda to promote the next generation of tools for reducing risk and improving competitiveness. Workshop participants identified that there were no standardized guidelines for conducting condition assessments and that there was a lack of protocols to help utilities better understand asset condition and performance. The workshop determined that undertaking condition assessment within an appropriate asset management framework would be a significant step forward for the water utility sector of the United States. For example, this step would enable a utility to better: Meet customer service expectations as well as legislative requirements. Determine the risk of failure (considering both failure probability and consequence) associated with different assets, and therefore, prioritize spending within limited budgets. Understand asset condition and remaining life, allowing for proactive budgeting for renewal/replacement of assets. 1-2

Quantify the benefits of different management/operational strategies. Determine asset value and comply with accounting standards. With these and other advantages in mind, a primary objective of this report is to demonstrate the important link between accepted and emerging principles of asset management and approaches to condition assessment. The report also provides information to facilitate the selection and effective use of condition assessment tools and techniques when undertaking asset inspection and condition monitoring within a framework of various levels of asset management sophistication. A comprehensive scope of tools is considered, covering those applicable to above and below ground assets (pipeline and non-pipeline assets) used in the delivery of potable and wastewater services. 1.2 Project Delivery This research project was undertaken in two overlapping phases. Phase 1 of the project involved a review of literature and other information sources and led to the drafting of a condition and performance assessment framework, along with an initial review of available tools and techniques. Phase 2 was undertaken as a refinement stage, where concepts developed in Phase 1 were developed further, drawing on the knowledge from a range of case study partners and professionals working within the sector. Phase 1 included a web-based industry survey undertaken as a means of obtaining baseline information about the sector in the United States (some responses were also obtained from utilities who accessed the survey in other countries). Phase 1 also included a review of the literature relating to asset management and condition assessment tools and techniques. This consisted of performing an initial electronic search of the literature using combinations of key words, screening results and developing lists of articles pertaining to above and below ground assets from journals, proceedings and conferences. This allowed a first pass assessment of the tools and techniques used for condition and performance assessment in various sectors to be made. These tools were researched further during Phase 2 of the project, drawing on information sources available to the research team, the academic and commercial literature and the Internet. Draft summaries of individual tools were then sent out to a range of industry professionals, including venders, researchers and users for peer review. A data collection spreadsheet that detailed all of the tools and techniques identified in the project was also sent to each reviewer. The reviewers were asked to use the spreadsheet to confirm the applicability of tools included on the list and to add any additional tools that were used by or known to them. Conceptual design of a range of condition and performance related protocols were also carried out in Phase 1, drawing on the available literature and the experience of the project team. These protocols were developed further in light of industry interactions carried out as part of the Phase 2 case studies. 1.3 Linkage to Related Research In conjunction with other WERF and AwwaRF projects, the project outputs will help utilities move towards better practice in both condition assessment and asset management. To this end, the reader is referred to the Sustainable Infrastructure Management Program Learning Environment (SIMPLE) tool accessible through the WERF web site (accessible to WERF members only): http://simple.ghd.com.au/default.aspx. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 1-3

SIMPLE is a web-based knowledge management tool that helps utilities in developing a life-cycle asset management approach. The tool guides utilities on how to determine the most cost-effective investments acquisition, maintenance, renewal in their asset portfolio, including how to extend the life of existing assets by implementing optimal maintenance practices and rehabilitation interventions. 1.4 Report Structure The report is presented in eight chapters: Chapter 2.0 Provides background information on accepted and emerging principles of asset management, why water and wastewater utilities (hereafter generally referred to as utilities ) undertake condition and performance assessments and the role such assessments should play in the overall strategic asset management process. Chapter 3.0 Discusses issues relating to the design of a condition assessment program for strategic asset management and presents a generic 10-step approach to this design. Chapter 4.0 Considers how a condition assessment program can be justified. Chapter 5.0 Provides background information on why utilities undertake condition and performance assessments and the role such assessments should play in day-to-day maintenance; this chapter also includes a generic approach to selecting techniques for condition monitoring. Chapter 6.0 Presents the approach developed in the project to aid the selection of condition assessment tools/techniques. Chapter 7.0 Summarizes the tools and techniques available for use with different assets. Chapter 8.0 Presents details of the case studies. Supporting appendices are presented at the end of the report: Appendix A: Utility Objectives and Related Key Performance Indicators Appendix B: Individual Drivers for Assessment Appendix C: Condition and Performance Assessment Criteria Appendix D: A Generic Condition Assessment Form Appendix E: Development of a Prototype Expert System Appendix F: Details of Available Tools and Techniques 1.4.1 Presentation of Detailed Information on Tools and Techniques The detailed information on condition assessment tools and techniques has also been built into a prototype electronic expert system to aid users in the tool/technique selection process (described in Appendix E). It is a recommendation of this project that the prototype be developed into a finished software tool and made available through the SIMPLE web site. For the purposes of this report, however, the detail of the tools and techniques reviewed in the project are incorporated into Appendix F, with selected summary information included in Chapter 7.0 of the report to guide selection. 1-4

1.4.2 Note on Case Study Insets Interactions with industry practitioners were undertaken throughout this research, particularly during Phase 2 when a range of case studies were undertaken with a number of utilities in the United States, Australia, New Zealand and the United Kingdom. The case studies are detailed in Chapter 8.0 of this report. Case Study Insets are also distributed throughout the report to provide practical insight into the points under discussion. In general, these insets provide summary information that has been drawn from one of the case studies detailed in Chapter 8.0. Where this is the case, the linkage to the case study is explicitly stated so the reader can refer to the relevant case study. In many cases, the full case study provides additional insight into the issues under discussion. 1.5 How to Use this Report The initial focus of this project was the consideration of condition assessment as a strategic asset management tool. Direction from the Project Steering Committee after completion of Phase 1, however, indicated that the focus of the project needed to be expanded to include the use of condition monitoring techniques in maintenance. As a result of this guidance, this report includes specific chapters relating to 1. Strategic Asset Management. 2. Maintenance Management. Chapters with a Strategic Asset Management Focus Readers interested in condition assessment from the perspective of strategic asset management are directed to the following chapters: Chapter 2.0 Reviews a range of issues related to strategic asset management. Chapter 3.0 Considers the design of condition and performance assessment programs from a strategic asset management perspective. Chapter 4.0 Outlines the approach to program justification using cost-benefit analysis. Chapter 6.0 Provides guidance on tool selection. Chapter 7.0 Considers the range of tools available for condition assessment. Chapter 8.0 Presents case studies. Chapters with a Maintenance Management Focus Readers interested in condition monitoring from the perspective of day-to-day maintenance are directed to the following chapters: Chapter 5.0 Outlines maintenance practices and the role condition monitoring plays in maintaining asset capabilities. Chapter 6.0 Provides guidance on tool selection. Chapter 7.0 Considers the range of tools available for condition assessment. Chapter 8.0 Presents case studies. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 1-5

1.6 Document Road Map To further facilitate the use of the report, an attempt has been made to anticipate questions a user may want to answer and to provide an indication of where in the document related information can be found. In line with the overall design of the document, questions are presented below and split according to the two target audiences: 1. Questions relevant to strategic asset managers. 2. Questions relevant to maintenance professionals. It is also anticipated that the user may want to access information relating to specific asset types, so an indication is also given as to where this information can be found within the report. 1.6.1 Road Map for Asset Managers Gaining a General Understanding of Condition Assessment and SAM What are the key elements of SAM and how is this discipline developing? See Section 2.2 and subsections. How is condition assessment used in SAM? See Section 2.3 and subsections. When should I undertake condition assessment for SAM purposes? See Section 2.4 and subsections and Appendix A and B. What is the link between condition assessment and a KPI management system? See Section 2.4.1 and Appendix A. Developing a Condition Assessment Program What role does asset risk play in the design of my program? See Section 3.2. What outputs can I expect from a condition assessment program? See Section 3.3. How do I design and use condition/performance grading system? See Section 3.3.3 and subsections; Appendix C. How do I design a condition assessment program itself? See Sections 3.4 to 3.5 and subsections. What factors do I consider in the design of an asset sample? See Section 3.4.5. What data and information should I collect during an assessment program? See Section 2.2.2, Section 3.6; Appendix D. 1-6

How do I go about justifying my condition assessment program? See Section 3.5. Information on Tools and Techniques What factors should I consider when selecting tools and techniques? See Chapters 6, specifically Table 6.1 and Table 6.2. How do I select which tools to use for a given asset type or situation? See Chapters 6 and 7, specifically Figure 6.1 and Table 7.6. I need information on a specific tool, where can I find this? See Appendix F. 1.6.2 Road Map for Maintenance Managers and Engineers Gaining a General Understanding of Proactive Maintenance What are the key elements of proactive maintenance programs? See Section 5.2 and subsections. How are asset inspections and performance monitoring used in such programs? See Section 5.3 and subsections. Developing Proactive Maintenance Programs What are risk-based assessment procedures in the context of maintenance? See Section 5.4. What types of risk-based assessment techniques are available? See Section 5.4.1 (for RCM) and Section 5.4.2 (for RBI). Is there a generic approach for specifying maintenance tasks on the basis of risk? See Section 5.5 and subsections. How do I develop and justify my condition monitoring program? See Section 5.6 and subsections. Selecting Appropriate Tools and Techniques How do I select condition assessment tools? See Chapter 6.0. What is the impact of asset risk on the tool selection process? See Section 6.6 and subsections. Should I use the most accurate (and expensive) tool available? See Section 6.7, specifically Figure 6.2 and Table 6.4. What factors should I consider when selecting tools and techniques? See Chapters 6.0, specifically Table 6.1 and 6.2. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 1-7

How do I select which tools to use for a given asset type or situation? See Chapters 6.0 and 7.0, specifically Figure 6.1 and Table 7.6. I need information on a specific tool, where can I find this? See Appendix F. 1.6.3 Asset Related Sections Multiple Asset Types Where can I find general information relating to asset-specific assessments? See Section 3.5.1 for summary approaches for a range of assets. Where can I find information relating to a generic (any asset) assessment program? See case study 3. Where can I find information relating to asset-specific assessment criteria? See Appendix C for condition and performance assessment criteria. Pipe Assets Where can I find information relating to water distribution pipes? See Sections 3.3.1 and 3.3.2; case studies 2, 10 and 12. Where can I find information relating to water transmission mains? See Inset 6-1 (Section 6-7); case studies 5 and 12. Where can I find information relating to gravity sewers? - See Section 3.3.3; case studies 6, 7and 10. Where can I find information relating to sewer force mains? See case study 13. Non-Pipe Assets Where can I find information relating to treatment work assessments? See Inset 5-5 (Section 5.4.1); case study 1. Where can I find information relating to mechanical and electrical assets? See Section 6.6, Inset 5.3 (Section 5.4.1); case studies 9, 11and Appendix D. Where can I find information relating to water tank assessments? See case studies 4 and 8. 1-8

CHAPTER 2.0 CONDITION ASSESSMENT AS A STRATEGIC ASSET MANAGEMENT TOOL Chapter Highlights Utilities share a common business driver: the need to provide sustained service delivery at an acceptable cost and in accordance with regulatory requirements. They provide this delivery of service through a combination of the utility s business and asset capabilities. A key business capability of a utility is its ability to effectively manage and maintain its asset stock. Strategic asset management philosophies have developed over time to facilitate this. The more advanced approaches focus on risk and service, rather than condition and performance. Condition assessment, however, remains a key component of risk-based asset management. Various levels of asset management sophistication can be identified (informal, core and advanced) and various drivers exist that create a tendency towards increasing levels of sophistication. Utilities should manage asset condition and performance within the context of the utility s overall asset management strategy and service level goals. Condition and performance assessment activities should be designed to fill specific assetrelated information gaps in order to facilitate decision making. Since condition and performance data collection and management is costly, it is important that a utility strive to collect only sufficient data to support the information needs of the business. Ideally, various measures of performance (key performance indicators or KPIs) would be used to drive asset management, with asset-level condition and performance assessments only being undertaken when there is a need for additional information. In practice, however, utilities need to undertake asset-level condition and performance assessments in response to a range of drivers unconnected with KPI management systems, not least because of the need to satisfy the requirements of regulators. Protocols for Assessing Condition and Performance of Water and Wastewater Assets 2-1

2.1 Introduction Utilities are tasked with supplying critical water and wastewater services to communities and the environment. From this perspective, a utility s business drivers are to provide sustained service delivery at an acceptable cost and in line with regulatory requirements such as the need to maintain water and environmental quality and give due regard to public health and safety. The capacity to deliver these services depends strongly on the business capabilities of the water utility (e.g., the people, processes, data and technology used within the business) and asset capabilities (e.g., the capacity, condition and performance of individual assets and systems). The concept that service levels are dictated by the utility s business drivers but underpinned by business and asset capabilities is illustrated in Figure 2-1. For example, business drivers such as customer expectations and requirements of regulators dictate the level of service that must be delivered, whereas asset and business capabilities impose a limit on the level of service that can be sustained over the long term. Where there is a disparity between the demand for service and the capacity to deliver that service, investment is required in the utility s asset and/or business capabilities. Figure 2-1. Business Drivers and Utility Capabilities. In an asset-intensive sector, one of the key business capabilities a utility can develop to facilitate service delivery is the effective management of its asset stock, which will in turn underpin the construction and maintenance of an asset base that has the capability to sustain the required service levels. As discussed in Chapters 3.0 and 4.0, effective management of assets requires both strategic management approaches and an effective approach to condition and performance assessments undertaken in support of strategic asset management. In this context, condition and performance assessments provide information on issues such as: The value of existing assets. Asset remaining life. The reasons for shortfalls in service provision. The potential for future problems; that is, the risk of failure (probability versus consequence) associated with different assets. 2-2

The way in which condition and performance assessments are used, however, varies significantly because of the range of asset management approaches adopted by different utilities. This chapter explores the concepts that underlie the approaches to asset management applied in the water sectors of countries such as the United States, Australia, New Zealand and the United Kingdom and illustrates the role condition and performance assessments plays within various asset management philosophies. Since the meaning of asset management varies significantly from practitioner to practitioner, the definition of asset management adopted within this project is first presented, along with an outline of the overall asset management cycle. The development of asset management and its underlying philosophies are then reviewed, including a discussion of the emerging drivers for greater asset management sophistication. A generic protocol for specifying when and where to undertake condition and performance assessments is then presented. An ideal approach that uses performance assessments based on KPIs to measure asset capabilities is outlined, along with a more pragmatic approach where the need for assessments is dictated by discrete drivers. Examples of protocols for undertaking condition assessment for the purposes of strategic management in other sectors are also presented. It should be noted that this chapter considers issues only from the perspective of strategic asset management (defined below). Issues relating to day-to-day maintenance management are discussed in Chapter 5.0. 2.2 Strategic Asset Management Asset management remains an ill-defined term, and many definitions exist in the literature. For example, Vanier & Rahman (2004) give the following definition: Asset management is a business process and decision-support framework that: (1) covers the extended service life of an asset, (2) draws from engineering as well as economics, and (3) considers a diverse range of assets. Similarly, the U.S. EPA (2002a) notes that: Asset management is a continuous process that guides the acquisition, use, and disposal of infrastructure assets to optimize service delivery and minimize costs over the asset s entire life. Notwithstanding the value of these definitions, for the purposes of this project, the following definition, modified from that given in the International Infrastructure Management Manual (IPWEA, 2006), is considered by the authors to encapsulate the main features of this emerging discipline as it is practiced today: The combination of management, financial, economic, engineering and other practices applied to physical assets with the objective of providing the required levels of service to customers and the environment at acceptable levels of risk and in the most efficient manner. While asset management is used as a general term throughout this report to indicate issues relating to this definition, the expression Strategic Asset Management (SAM) is also used to differentiate practices specifically with a medium to long term view, from those practices specifically with a short to medium term view, which are considered to be part of maintenance management discussed in Chapter 5.0. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 2-3

Many practitioners refer to asset management with a medium view as Tactical Asset Management, however, this term is not used within this work. 2.2.1 Asset Management as a Framework The adoption of formal asset management by utilities has generally lagged behind the development of the asset stock. As such, asset management has commonly evolved and developed around existing utility systems and in light of existing assets. When starting to implement formal asset management approaches, utilities generally begin from a position of poor knowledge regarding the asset stock. However, as discussed in Section 2.2.2, a fundamental requirement of all asset management systems is information on the assets. Utilities in this position must therefore address the six whats of asset management (Vanier, 2000 & 2001): 1. What assets are owned? 2. What are they worth? 3. What is the deferred maintenance? (In this context, deferred maintenance is taken to be an overview of the amount of expenditure required to bring the maintenance and repair under control, rather than being a measure of renewal backlog). 4. What condition are the assets in? 5. What is the remaining service life of the assets? 6. What should be fixed first? Various asset management tools and approaches are needed to help answer these questions. In particular, condition and performance assessment are widely used, not least because they provide the information required to answer the last three of the whats of asset management listed above. While these tools are important to the implementation of asset management, it should be understood that they are not asset management per se. Instead, it is useful to consider asset management as a framework within which various tools and approaches are applied. For example, the Publicly Available Standard for asset management (PAS 55) in the United Kingdom (BSI, 2004), provides a complex framework (scope) for asset management, which for most practical purposes can be simplified to the process shown in Figure 2-2. It is interesting to note that the later steps in Figure 2-2 (set condition and performance targets, produce asset management plans, and implement and operate) indicate that the on-going management of asset condition and performance is a key aspect of this framework. Management of asset condition and performance can only be achieved if appropriate measures are available to compare against the condition and performance targets, so the implementation of this particular framework would, like the six whats of asset management given above, explicitly drive the requirement for condition and performance assessments. However, as will be discussed later, management of condition and performance is just one asset management philosophy adopted in the water sector. The reader is referred to national and international standards for more information on asset management frameworks (for example, IPWEA, 2006; BSI, 2004). 2-4

Figure 2-2. The PAS 55 Physical Asset Management Framework. 2.2.2 The Role of Asset Data and Data Systems As noted in section 2.2.1, the first what of asset management requires a utility to determine what assets are owned. An asset inventory (generally a formal list of assets, broken down into an appropriate hierarchy and keyed with a unique tag number) is thus essential to asset management. Furthermore, as illustrated in Figure 2-2, implementation of an asset management framework is not a static process monitoring, review and improvement of all stages are essential. This requires a formalized feedback loop that leads to corrective actions, improvements and evolution of the process in question. This feedback in turn relies upon having sufficient data capture/collection and associated procedures. For these and other reasons, data is fundamental to all asset management systems. It is important to establish and maintain an up-to-date inventory of assets and to combine this with a database of other asset-related data items (commonly implemented as a computerized maintenance management system and/or a geographical information system). Creating such a database is not a trivial task and may require several years and revisions (e.g. Zhao, 1998). Data items incorporated into the database(s) will vary from asset type to asset type. For example, Newton & Vanier (2006) state that the minimum sewer pipe physical data should be the pipe location, length, material, diameter and year of construction. The next level of inventory data includes invert depth, type of backfill, bedding material and ground water level, which are important factors to consider when determining pipe condition. More generally, asset data is required on: Asset physical aspects (asset type, material, rating, age, etc.) Asset location and/or geo-reference Design and construction information Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 2-5

Operational context Environmental conditions Information on reported defects and failures Maintenance and inspection records Given the large number of assets involved in the provision of water and wastewater services, there is potentially a great deal of data that could be included in a database. However, since data collection and management is costly, it is important that a utility collect only sufficient data to support the information needs of the business. This concept is illustrated in Figure 2-3, which shows the relationship between data, business processes and information needs. To optimize data collection, the utility should first consider the business information needs, which will then dictate what input data are relevant, including the amount of asset condition and performance data required. This mapping needs to be reviewed periodically as business information and data needs change due to changes in emphasis given to different management issues, changes in regulation, and so forth. Figure 2-3. Determining Data Requirements through Information Needs. 2.2.3 Strategic Asset Management Philosophies The flow chart presented in Figure 2-2 indicates a focus on the management of asset condition and performance. However, other asset management approaches exist. In fact, the asset management approaches applied in the water sectors of countries such as the United States, Australia and the United Kingdom can be characterized in terms of a succession of dominant philosophies. In reality, each successive approach has built on the previous one(s), so any explicit division is somewhat artificial. Nevertheless, for the purposes of this discussion, it is useful to consider the approaches as distinct. The following list indicates the staged development of increasing asset management sophistication: Condition-based asset management Performance-based asset management Service-based (service level driven) asset management Risk-based asset management In condition-based asset management, expenditure is focused on maintaining what assets are (the condition they are in). This is a natural approach for engineers to adopt; if the condition is poor, the asset needs maintenance/investment to rectify defects. In a similar vein, performance-based asset management focuses on what assets do in a local sense; that is, the question is posed, is the asset doing the job that it was intended to? 2-6

(This question can often be related to the asset s condition, but may not be.) If not, maintenance and/or capital investment are required. Again, this is a natural way for engineers to consider management of assets. A more customer-focused approach is taken in service-based asset management. Performance is not viewed in terms of local considerations (the design intent of individual assets), but instead is considered in more inclusive terms and at a higher level. The question is posed, is the asset contributing appropriately to the delivery of service? This consideration is made independently of asset condition or its performance relative to design intent. Service-based asset management thus seeks to maintain the service provided by the asset stock at both the local and regional level. Due consideration is normally given to the need to deliver at least minimum levels of service to all customers. This approach is less intuitive for engineers, since it can mean that maintenance/investment is not always justified for poor condition assets or even poor performing assets where the impact on service is acceptable. Risk-based asset management seeks to achieve optimum life cycle management of assets through consideration of risk to service provision, with risk generally being defined as the product of probability of failure and consequence of failure. The condition and performance of an asset are simply factors in the assessment of risk. Other factors taken into account include business risk factors such as those associated with safety and the environment, customer expectations, reliability, efficiency and effectiveness, finance, reputation and regulatory relationships. In the web-based industry survey undertaken as part of this research, surveyed utilities were asked to specify which of these categories best described their approach to asset management. The results are shown in Table 2-1 for a sample of 30 respondents, 21 of which were from the United States. The table shows that there is a wide range of philosophies still being adopted within the sector, and that nearly one-third of the respondents indicated that there was no defined strategy being used. Table 2-1. Approaches to Asset Management Adopted. Asset management approach adopted Proportion Condition-based 28% Performance-based 19% Service-based 10% Risk-based 14% No defined strategy 29% 2.2.4 The Building Blocks of Asset Management Whatever philosophy is adopted, it can be generally stated that SAM seeks to optimize a utility s expenditure by determining the most appropriate time to intervene in the asset deterioration process to maintain service delivery at an acceptable level of business risk and within budget. Since assets deteriorate over different periods, asset management is thus undertaken within the context of the life cycle of the asset stock and can be considered a cyclic process of asset-related tasks, as shown in Figure 2-4. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 2-7

Figure 2-4. The Asset Management Cycle. From the categorizations given in Table 2-1, it is clear that utilities address the asset management cycle shown in Figure 2-4 in a variety of ways. Nevertheless, all utilities must, in broad terms, deliver the same range of core services and manage an asset stock throughout its life cycle. As such, all utilities must address various asset management building blocks in some way, even when the overall asset management approach is not formalized. These include the asset-related tasks shown in the asset management cycle (Figure 2-4), as well as other fundamental building blocks such as: Asset information Condition and performance assessments Risk management Planning for maintenance and renewals Optimizing asset investment Monitoring service provision Setting appropriate pricing The level of asset management adopted to co-ordinate and align these building blocks depends in part on the utility s business environment. For example, the more exacting the service mandates are in relation to budgetary constraints, the more sophisticated the asset and business capabilities need to be; these conditions then drive the need for adopting formalized asset management approaches. 2.2.5 Three Levels of Strategic Asset Management The International Infrastructure Management Manual (IPWEA, 2006) defines two levels of formal asset management: core and advanced. Core asset management relies primarily on the use of an asset register, maintenance management systems, job/resource management, inventory control, condition assessment and defined levels of service, in order to select appropriate interventions and make long-term 2-8

cash flow predictions. Priorities are usually established based on financial return rather than risk analysis and optimized decision making. Advanced asset management employs predictive modeling, risk management and optimized decision making techniques to establish asset lifecycle intervention options and related longterm cash flow predictions. Advanced asset management is heavily reliant on the use of computerized systems and is possible only when detailed data on assets are available. However, since data quality improves over time as it becomes embedded within a business as usual environment, early adoption of advanced asset management approaches can act as a facilitator for improving the quality and accuracy of data. Since the results given in Table 2-1 indicate that 29% of respondents have no defined strategy for asset management, it can be inferred that a significant proportion of utilities in the United States have not yet implemented core asset management, as defined in the International Infrastructure Management Manual (IPWEA, 2006). As noted above, however, in an asset intensive sector, all utilities must be undertaking management of assets in one form or another. As such, for the purposes of this project, utilities undertaking management of assets without adopting a formal approach to SAM, were deemed to be applying a third level, which can be termed Informal Asset Management. 2.2.6 The Drive Toward Increasing Asset Management Sophistication If there were no drive towards greater sophistication, it can be assumed that informal asset management approaches would remain in place, since these are the least expensive approaches to implement. In the United States, as with other countries, an informal approach has been acceptable in the past; however, this trend appears to be shifting. Some of the drivers behind this shift include decreased availability of federal grants for capital projects, and more stringent service and cost drivers. Rast (2003) identified four key drivers for the adoption of formal asset management approaches in the United States: Changes in demands placed on infrastructure and budgets. Changes in public perception relating to asset management. Changes in regulatory requirements. Availability of new technology. The first of these drivers relates to the combination of increased demand on infrastructure systems combined with a significant budget shortfall. The second driver relates to public perception of the management of infrastructure assets and a growing awareness of the impact of aging infrastructure and environmental factors on water quality and quantity. In a similar vein, the U.S. Department of Transport (US DoT, 1999) noted that asset owners will be facing increased system and budget needs with limited staff resources. At the same time, individual states will be required to deal with increased system complexity and public demands for accountability and expectations regarding levels of service. As noted in Chapter 1.0 of this report, these demands are occurring at a time of deteriorating asset stocks. The third driver noted by Rast (2003) is a change in regulations, which promote and/or require the adoption of asset management principles. These regulations include the U.S. Government Accounting Standards Board (GASB) issued Statement No. 34, and Capacity assurance, Management, Operation and Maintenance (CMOM), discussed further in Case Study Insets 2-1 and 2-2. The final driver is the availability of new computer technology, which has Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 2-9

prompted a significant increase in the availability of tools (e.g. GIS and hydraulic models) that can assist in the complex analysis and decision making required for formal asset management. Case Study Inset 2-1: GASB 34 In June 1999, the U.S. Government Accounting Standards Board (GASB) issued Statement No. 34 (GASB 34), Basic Financial Statements for State and Local Governments (GASB, 1999). GASB 34 requires state and local agencies to produce financial reports in a manner more consistent with that used by private sector companies. In particular, GASB 34 requires infrastructure to be reported at its historical value and then depreciated. However, the GASB 34 requirements also allow for a modified approach for infrastructure assets that are part of a network or subsystem of a network. With this modified approach, assets do not have to be depreciated if two criteria are met, namely, 1) the public agency manages the asset using an asset management system and 2) the agency demonstrates that the assets are being preserved at, or above, an established condition level. The asset management system should: Have an up-to-date inventory of assets. Perform condition assessment of the infrastructure assets at least once every three years. Estimate the annual investment required to maintain and preserve the infrastructure assets at the condition level originally established for those assets. GASB 34 therefore offers utilities the option of reporting the system at full historical cost, rather than reporting depreciation, as long as asset management practices are adopted (U.S. DoT 1999). Under the modified approach, maintenance and preservation costs are expensed and only additions and improvements to the system are capitalized (U.S. EPA. 2002a). Case Study Inset 2-2: CMOM Capacity assurance, Management, Operation and Maintenance (CMOM was developed by the U.S. EPA in conjunction with municipal and other industry representatives. CMOM is an information-based approach to setting priorities for activities and investments in sewer collection systems. CMOM embodies many asset management principles as they apply to collection systems. These include defining goals, using an information-based approach to set priorities, evaluating capacity and taking steps to ensure capacity is adequate, developing a dynamic, strategic approach to preventive maintenance and conducting periodic program audits to identify program deficiencies and ways to address those deficiencies (U.S. EPA, 2002a). 2.2.7 Economies of Scale in Asset Management As a direct consequence of these drivers, United States utility managers are more frequently being asked to adopt more sophisticated asset management practices. The dominant belief is now that affordable technology is available to facilitate data and information management, the adoption of a strategic asset management philosophy will focus capital, 2-10

operational and maintenance strategies on the achievement of strategic business objectives and deliver them in a cost effect manner and at an acceptable level of risk. The added value (perceived or actual) realized by investing in asset management approaches will, to a degree, depend on the size and complexity of the utility s operations. The issue of affordability and cost-benefits need to be considered in all cases, but economies of scale favor the larger utility. For example, Shaw (2001) indicated that it is possible to increase the assets under management without a proportional increase in asset management overheads. Table 2-2, gives an indication of how asset management labor input, in terms of full time equivalents; (FTEs), might vary with the value of assets being managed. Table 2-2. The Impact of Scale on Asset Management Resources (after Shaw 2001). Asset management FTEs Asset base Asset base x 2 Asset base x 4 114.8 FTEs 134.3 FTEs 179.3 FTEs (25% increase) (67% increase) While such economies of scale may well exist, this does not preclude smaller utilities from adopting sophisticated strategies for the management of specific asset types. For example, small utilities may (and do) adopt sophisticated geographical information system (GIS) based analytical approaches for the management of pipe networks. 2.3 Condition Assessment as an Input to Strategic Asset Management As discussed in previous sections, there has been a succession of asset management philosophies (from a focus on asset condition and performance, to a focus on service provision and business risk) and an increase in asset management sophistication in the utility sectors of a number of countries. Since the more developed asset management philosophies do not focus on asset condition, it can be concluded that SAM does not seek to manage asset condition or performance per se. For many types of assets, however, there is a general relationship between age, condition and the asset s propensity to fail, as illustrated schematically in Figure 2-5. Such relationships occur when failure mechanisms such as fatigue, corrosion and wearout start to predominate as the asset reaches the end of its useful life. The rate of deterioration (i.e., the worsening of condition and/or performance) is highly asset and context-specific, and depends upon such factors as the type and design of the asset, the existence of deterioration mechanisms such as corrosion and wear, any protection systems used, local environmental conditions, its operating context and the maintenance strategy adopted. Relationships such as those illustrated in Figure 2-5 are seldom straightforward. Nevertheless, the condition and performance of many types of assets progressively deteriorate over a characteristic timescale, eventually reaching the point where they need to be replaced or rehabilitated because they are uneconomic to operate, provide unacceptable performance or are deemed to represent too high a risk. Given theses considerations, although it is true that SAM does not seek to manage asset condition as such, measures of asset condition and performance are clearly an important input into asset management decision making and other processes. In turn, the development of asset management processes also facilitates the effective implementation of condition assessments, as summarized in Case Study Inset 2-3. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 2-11

Figure 2-5. The Relationship between Asset Condition, Age and Failure Probability. Case Study Inset 2-3: Increasing Condition Assessment Effectiveness through SAM When it was corporatized in the early 1990 s, Melbourne Water inherited a fragmented approach to the management of its water tanks. Basic information relating to the construction of the tanks was available in the form of design drawings. However, on-going assessments were undertaken separately by various departments focusing on individual issues, such as corrosion, mechanical and electrical components, valves, etc. Information recorded during these assessments was in a summary format (e.g., asset satisfactory ) and not collated together. It was recognized that this assessment strategy did not provide the information required to support effective stewardship of complex assets. As such, Melbourne Water started to develop a structured approach to the management of these assets. Asset specific policies and procedures were developed, in line with the development of corporate risk and asset management policies, and with appropriate resourcing and lines of responsibility. Subsequent experience within Melbourne Water has shown that detailed investigations can be required when there is an unexpected failure or deterioration of any asset. The ability to undertake these investigations and implement risk management strategies is greatly enhanced by the development of asset management approaches. See Case Study 8 in Chapter 8.0. 2.3.1 The Role of Condition Assessment The challenge a utility faces is not managing the deterioration of one asset, or even one asset type, but managing the on-going deterioration of numerous assets, of many types, with different time scales of deterioration (months to many years), being affected by a vast array of environmental and operational context and having differing impacts on the utility s operations and budgets. To maintain service into the future in an affordable way, the utility must therefore understand the change in structural condition of all its assets, both spatially and temporally. Condition assessment can be used to develop or enhance this understanding in conjunction with assessments of performance undertaken at both asset-specific and system levels. In fact, the U.S. EPA (2002b) noted that 1) the best way to determine the remaining useful life of a system is to conduct periodic condition assessments, and 2) that it is essential for utilities to complete 2-12

periodic condition assessments in order to make the best life-cycle decisions regarding maintenance and replacement. In addition to playing a key role in the assessment and understanding of asset deterioration, condition and performance assessments can also provide information to meet other strategic asset management needs, for example: What assets are worth. How assets are performing in relation to requirements (in some cases, this involves comparing asset performance to service measures). The impact of operation and maintenance practices on asset condition and performance. Case Study Inset 2-4 illustrates the role condition and performance assessments can play in regulatory reporting, which encapsulate these issues. Case Study Inset 2-4: Use of Condition and Performance Assessment in Reporting In Scotland, the assessment of asset condition and performance was required by the Economic regulator for Scotland and included in the Asset Inventory and System Performance Submission (Table H). Table H was part of the Scottish Water s annual reporting requirements and summarized the asset stock, its condition and performance and value (modern equivalent). The guidance notes for the production of Table H indicated the information in the table would form a record of the asset stock and provide a strategic framework of investment levels for sustainable stewardship for coming years. The stated objectives of Table H were to: 1. Enable Scottish Water to produce a strategic framework that provided asset stewardship output measures, set against investment levels for each asset category. 2. Enable Scottish Water to demonstrate that asset information was adequate and that the Authority had a comprehensive and systematic basis for the long-term stewardship of the assets in regard to financial performance and customer service. 3. Enable Scottish Water to summarize the latest investigations and audits of their asset stock. This included the level of risk, condition, age and performance of assets. See Case Studies 1 and 2 in Chapter 8.0. 2.3.2 Data Requirements for Condition and Performance Assessments The assessment of asset condition and performance involves the collection of data using inspection tools/techniques. However, even at the asset level, this data is insufficient for decision making because the condition of an asset does not in itself indicate whether an intervention is required. Understanding condition requires other data from utility systems and/or surveys to allow interpretation and contextualization of the results. In a wider context, understanding asset condition is only part of the decision making process. As such, the utility will also need to supplement condition and performance data with a range of other asset-related data, including: What the consequences of asset failure are (at a local and system level). What it will cost to replace/rehabilitate the assets. What alternatives exist, given the results of the condition and performance assessment (partial replacement, non-structural repair, deferment, etc.). Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 2-13

2.4 When to Undertake Condition Assessment One challenge for this project was to consider the application of condition assessment for the whole range of asset management approaches currently in use; from informal asset management through to advanced asset management. To this end, the project team determined what it considers to be the ideal practice for specifying the need for condition assessment, while allowing for the fact that a significant proportion of utilities will not be in a position to adopt this ideal. (It should be noted that the use of the term ideal practice does not imply each utility should aim to adopt this approach; what is practical and affordable also needs to be taken into account best practice for a given utility must be considered in terms of its business drivers, existing systems and available budgets.) The first step in developing an assessment program that will allow the utility to control costs and sustain the desired level of service is the definition of required system-level performance standards (ASCE, 2004). As such, and to aid discussion of the ideal route for specifying condition assessment, it is worthwhile considering first the development of appropriate performance standards, and then showing how the strategic measures of asset management performance generated can be used to specify the need for asset-level condition and performance assessments. 2.4.1 Strategic Goals and Performance Management Each utility has a range of institutional aspirations (things the utility wants to do) and imperatives (things the utility must do), commonly expressed in the form of business goals. These business goals will in turn reflect the requirements of stakeholders and customers, and will in part depend on the ownership model adopted (whether a public council/authority or private business). Ideally, the utility will establish strategic objectives that embody these goals and imperatives, select appropriate KPIs and set corresponding targets that will allow the utility to measure progress towards the strategic objectives, as well as measure operational/maintenance performance. Case Study Insets 2-5 and 2-6 show a number of relevant KPIs and associated targets for two of the case study partners in the United States. The process of defining relevant KPIs is illustrated in Figure 2-6. The targets and requirements box shows how the KPIs feed into the asset management cycle shown in Figure 2-4 (via the targets and requirements box in Figure 2-4). Utilities need a set of KPIs that measure performance across a range of business activities. Various types of KPIs can be specified, including: level of service KPIs; asset-related KPIs; and derived KPIs. For the purposes of this work, these are defined as follows: Level of service KPIs (e.g., interruptions to service) give a measure of service as perceived by the customer or environment and are an indirect measure of asset condition and performance. These KPIs are often the driver behind asset management expenditure and prioritization processes. Asset related KPIs (e.g., equipment or pipe failures) give a measure that can be related directly to asset condition or performance. These KPIs are often used to target and prioritize asset management expenditure effectively. 2-14

Derived KPIs (e.g., amount of rehabilitation and annual investment) are those that measure asset management effort. These KPIs can reflect asset condition and performance, but are strongly influenced by policy decisions and available budgets. Figure 2-6. The Process of Developing a Performance Management System. Case Study Inset 2-5: KPIs and Targets for a U.S. Utility Massachusetts Water Resources Authority (MWRA) uses an extensive set of KPIs to measure performance aspects of operations and maintenance programs; for example: Equipment availability (exceeds industry benchmark of 97%). Replacement asset value per maintenance technician (exceeds industry best in class target range of $8M to $10M). Maintenance cost/replacement asset value (in range of industry benchmark of 1-2%). Preventive maintenance compliance > 95% per month completed. Predictive maintenance is increasing and currently accounts for 10% of all work orders. See Case Studies 11 and 12 in Chapter 8.0. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 2-15

Case Study Inset 2-6: KPIs and Targets for a U.S. Council The City of Bellevue Council uses a suite of KPIs to drive asset management programs. KPIs are organized according to effectiveness, efficiency and staff workload. Certain effectiveness KPIs, such as water service interruptions, sewer system dry weather overflows and claims relate to overall condition and performance of assets. KPIs and associated targets relevant to this research include: Customer satisfaction rating (target > 85%). Claims per year (target <10 (wastewater) and <5 (water), with no single claim greater than $20,000). Water service interruptions (target < 3 per 1,000 service connections). Wastewater pump station overflows (target<0.11 per 1,000 service connections). Sewer main line stoppages per year (target < 0.4 per 1,000 service connections). Percent completion of planned inspection programs (target 100%). See Case Study 10 in Chapter 8.0. Once an appropriate set of KPIs is selected and targets set, the data needed for KPI measurement must be collected and/or collated as a routine activity and analyzed in an appropriate manner. This includes analysis of supporting statistics required to help understand variations and trends in KPIs. Analysis of KPIs can be undertaken at a range of granularities (local to utility wide), as an on-going management task and as a feed into periodic planning cycles for capital investment, such as in Case Study Inset 2-7. Aitkin and Davis (2001) note that performance monitoring of this type: 1. Provides a comprehensive picture of how the utility is progressing towards achieving its strategic goals. 2. Provides early indications of emerging issues that may require remedial action. 3. Establishes a basis for service standard, resource and pricing negotiations between stakeholders. 4. Provides a logical and defensible basis for changes in policy and/or practices and the pursuit of negotiations with external stakeholders (e.g., customers and regulators). The comparison of measured KPIs to the associated targets, in conjunction with trending analysis, also informs and drives asset management effort; a shortfall in a KPI measured against its target indicates that a strategic objective is not being met and that some action is required. For example, Table 2-3 shows a number of strategic objectives and related KPIs applicable to the management of water supply assets, along with an outline of the approaches used to assess why a shortfall exists in the KPIs against targets. A more comprehensive list of strategic objectives and related KPIs for both water and wastewater services is provided in Appendix A. 2-16

Case Study Inset 2-7: Investment Planning through KPI Assessments An approach akin to the high-level performance monitoring protocol was used by Scottish Water in Quality and Standards (Q&S) II. Q&S II involved planned investment of 1.8 billion between April 2002 and March 2006. Bursts and quality KPIs were used in a condition and performance matrix to identify problem water supply zones. Once identified, more detailed studies were undertaken. A strategic gap analysis was also undertaken by Scottish Water as part of its third investment planning cycle; referred to as Q&S III. Q&S III spans April 2006 to March 2014. This gap analysis was essentially a systematic review of asset capabilities and service provision compared to current and future targets, so as to identify where investment was needed. This involved assessment of a range of KPIs and other data. As is the general practice in the United Kingdom, the resulting investment program was driven by gaps in service levels and KPIs. See Case Study 1 in Chapter 8.0. Table 2-3. Strategic Objectives, Related KPIs and Approach to Assessment. Strategic Objective KPI Outline of Assessment Approach Improve water quality (WQ) WQ compliance at works Turbidity at works Invest in measures to reduce discolored water complaints Improve drinking taste and odor Improve pressure of water supply to customers at risk of low pressure Reduce interruptions to supply WQ compliance at tap Coliform compliance (works, service reservoirs) Iron pick up in system Number of complaints Unplanned interruptions Interruption duration Interruption frequency Water pumping station failures Bursts per unit length Identify problem zones through analysis of complaints and sample data. Undertake a program of assessments to determine the root cause (works capacity, pipe condition, etc.). Preferably combine assessment with other service problems so as to ensure an integrated approach is taken and, eventually, interventions identified that give the best value for money. Identify problem zones/cohorts through analysis of failure event and sample data. Undertake a program of assessments to determine the root cause. Again, preferable to combine analysis with other service problems so as to ensure an integrated approach is taken and, eventually, interventions identified that give the best value for money. 2.4.2 Specifying Condition Assessment to Fill an Information Gap While this high level monitoring of utility performance (in combination with on-going monitoring of the condition/performance of individual assets, discussed more fully in Chapter 5.0) is a corner stone of asset management, routine activities do not generate all the data that is needed to manage the asset stock and support decision making. This is especially true for below ground assets that are hidden from view and can operate for many years before deterioration is sufficient to cause operational issues. For example, a network of water transmission pipelines may operate satisfactorily for many years with little or no operational failure data being Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 2-17

generated. However, the assets are still deteriorating at an unknown rate and eventually will start to fail, potentially with unacceptable consequences. Even when strategic performance management is undertaken effectively, there is still a gap in the information required to manage the assets, which can be filled by undertaking assetlevel condition and performance assessments. Figure 2-7 illustrates the process of using level of service and asset related KPIs as a means of undertaking high-level performance assessment to drive SAM decision making, only undertaking asset-level condition and performance assessments specifically for the purposes of SAM where it is needed to fill a gap in the information arising from this performance monitoring. Figure 2-7. The Role of Condition Assessment in Utility Decision Making. 2-18

It should be noted that the approach implicit in Figure 2-7 does not, in any way, imply that condition assessment/monitoring should not be undertaken routinely by a utility for the purposes of managing individual assets (see Chapter 5.0); it is only condition assessment undertaken specifically for the purposes of informing SAM decision making that is being considered here. As in Figure 2-6, Figure 2-7 illustrates that a set of KPIs is used that embody the utility s strategic objectives. Data from routine operations and maintenance feed assessment of performance through KPI measurement and thereby supports decision making. A gap in the asset-related information from this KPI management system drives the need for undertaking condition and performance assessment at the asset level. 2.4.3 Alternative Routes for Specifying Condition Assessment This formalized approach to KPI management, which only uses asset-level condition and performance assessment for the purposes of SAM to fill specific information gaps (as illustrated in Figure 2-7), is considered ideal practice. However, asset-level condition and performance assessment can also be undertaken without any formal asset management approach being in place or because some form of internal or external driver is imposed on the utility that necessitates the assessment. For example, there may be a requirement to report the overall condition of the asset stock to a regulator, or to undertake condition assessment as part of financial reporting procedures. Both of these drivers are independent of the ideal route for specifying the need for asset-level condition and performance assessment. This alternative route, which is (or can be) independent of KPI management systems, is also depicted in Figure 2-7 as the steps below the horizontal dotted line and shown separately in Figure 2-8 for clarity. Figure 2-8. Condition Assessment Undertaken in Response to Individual Drivers. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 2-19

A range of individual drivers for specifying the need for asset-level condition and performance assessments can be identified. For example, Table 2-4 lists a number of individual drivers for undertaking condition and performance assessments. In essence, each driver still relates to a gap in information that has to be filled, but the driver does not arise out of the management of KPIs. A more comprehensive list of individual drivers for undertaking condition and performance assessments is provided in Appendix B. Table 2-4. Drivers for Undertaking Condition and Performance Assessment. Focus Driver Asset type Assess renewal budgets and Condition and performance assessment to provide data for use Any asset type. timing of spend. in budget setting and/or justification of capital deferment. Prioritize capital programs. Determine appropriate intervention. Financial reporting (GASB 34 modified approach). Condition and performance assessment to target priorities for renewal spend. Condition assessment to determine the level of renovation required and specify rehabilitation approach; selection of least whole life costing approach (partial replacement, lining, etc.). Regulatory driver. Any asset type. Any asset type, but more likely to be pipes. All assets. Forensic investigations. Condition assessment to understand failure and support litigation. Any asset type. A clear case where the need for assessment and investigation is not driven by high level performance measures is where there is an unexpected and serious failure of an asset, as described in Case Study Inset 2-8. It should be emphasized that, except where the driver is imposed by an external body (e.g., a regulator), this disjointed approach to specifying the need for a condition and performance assessment program is not deemed ideal practice, although it may be appropriate practice for a given utility taking into account its drivers and particular circumstances. Case Study Inset 2-8: A Forensic Investigation of a Trunk Main Failure Water Corporation (West Australia) incurred a catastrophic failure of a trunk main, which lead to severe traffic disruption as well as other impacts. Given the unusual circumstances of the failure and failure mode, Water Corporation instigated a detailed condition assessment of the trunk main, in conjunction with an assessment of risk, to determine if the particulars of the failure represented an isolated case. The investigations were undertaken to: Identify any sections of pipe where a similar failure mode could occur (other locations where drainage infrastructure intersected the trunk main). Investigate the condition of the asset in sections where similar levels of failure consequence could be incurred. The investigations were designed to improve knowledge of the likelihood of further failure so that the risk of the main failing could be better managed. See Case Study 5 in Chapter 8.0. 2-20

Chapter Highlights CHAPTER 3.0 DEVELOPING AN ASSESSMENT PROGRAM The greatest value from condition assessment is gained when efforts focus on the more critical (higher consequence of failure) assets. When undertaking condition assessments, inspection data is collected through a number of tools and provides information on such things as the presence of defects and their severity. Data collected during inspection of assets must also be contextualized through appropriate analysis to give an assessment of condition in terms of the operating demands placed on the asset. Outputs of the condition assessment process can be expressed in a variety of ways. For example, probability of failure, remaining life estimations and condition and/or performance grades are commonly used. Condition data collected over time can yield deterioration curves that can aid in the estimation of asset remaining life; in addition to condition, performance standards and/or risk factors should influence the age at which assets are considered for renewal. Condition and performance grading systems enable a useful categorization of assets and summary of information collected to date on individual assets. A 10-step approach to specifying a condition assessment program is offered to align information collection efforts with utility drivers and objectives as well as decision support needs: Step 1. Step 2. Step 3. Step 4. Step 5. Step 6. Step 7. Step 8. Step 9. Document program drivers. Specify program objectives. Identify asset types to assess. Collate and analyze available data. Determine what assets to inspect, if any. Select inspection/assessment technique. Plan inspection program to minimize cost. Undertake asset inspection and other data collection. Analyze data and assess asset condition. Step 10. Utilize condition assessment information for decision making. In addition to these 10 steps, documentation and reporting of the overall process, data and information collected must be implemented as an ongoing process. To this end, there is a need for effective data collection forms and information management systems Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 3-1

3.1 Introduction As discussed in Chapter 2.0, asset-level condition and performance assessments can be undertaken in response to a number of strategic asset management drivers. These assessments involve the collection of data using inspection tools/techniques, but other data are also required to allow interpretation and contextualization of the results. When designing an assessment program, it is thus necessary to have an understanding of what data are to be collected and how the data are to be analyzed and used. Assessing condition first requires an understanding of the assets and the business needs that are driving the condition assessment. The process of condition and performance assessment then involves a number of distinct steps, for example, determining what assets to inspect and selecting tools for use. This chapter describes the generic steps involved when designing an effective assessment program. The role of risk in condition assessment is first discussed, followed by a consideration of the outputs of the assessment process that may be sought. A number of protocols used in developing condition assessment programs are then presented, including a detailed treatment of the generic 10-step process adopted in this research. 3.2 The Role of Risk in the Design of an Assessment Program As noted by Rahman & Vanier (2004), one of the functions of condition assessment is to establish the current condition of assets as a means of prioritizing maintenance and rehabilitation effort. Some assets are more important than others are, and asset condition is only one of the metrics used when prioritizing interventions. Other measures are required that provide information on the importance of the asset as well as the cost and benefits of available options. A standard way to characterize the importance of an asset is to evaluate the risk of failure. Risk is determined by taking into account both the probability and consequence of asset failure. However, since consequences are related to the asset s operational context and system configuration, the potential consequences of asset failure generally remain relatively constant over time. As such, consequence of failure is often used on its own to determine whether a proactive or reactive maintenance strategy should be adopted, as shown in Figure 3-1. In contrast, as discussed in Section 2.3, the probability of failure of many asset types does not stay constant, but increases over the life of the asset as it deteriorates. Condition assessment can therefore be used to understand the level of asset deterioration and the impact this has on the probability of failure. The utility can then attempt to reduce that probability of failure through some operational or capital intervention or accept the level of risk associated with the asset s condition. When an intervention is carried out as a result of the assessment, the benefit derived is proportional to both the reduction in probability of failure and the expected consequence of that failure. This potential benefit (often difficult to quantify) must be balanced against the cost of undertaking the assessment and subsequent interventions. When undertaken as part of a risk management strategy, condition assessment is only warranted when it has the potential for facilitating improved management of service delivery or has for reducing risk sufficiently to justify the cost of the assessments. Where no action is taken 3-2

as a result of an assessment, the benefit is then implicit in the improved knowledge of the asset and asset base. From the perspective of risk and cost effectiveness, a utility will realize the greatest value from condition assessments by targeting its resources on more critical (higher consequence of failure) assets. This concept is embedded in the maintenance strategies shown in Figure 3-1, which requires condition assessment to be undertaken for high consequence assets (this topic is considered further in Chapter 5.0). Figure 3-1. Risk and Maintenance Strategies (adapted from Buckland, 2000). While targeting important assets for condition assessment is standard practice, some utilities perform condition assessment on each asset in their system to improve asset information. Depending on the level of detail used, this approach could divert important resources away from more urgent needs associated with the highest-risk assets. In some cases, this type of requirement is imposed by a regulator, as in Case Study Inset 3-1. Condition assessment is also undertaken within many utilities to understand the condition and/or rate of deterioration of populations of assets that individually have a low failure consequence, but together represent a significant investment. This is often done to justify a replacement budget and involves the use of sampling programs, as described more fully in Section 3.4.5 and Case Study 2 in Chapter 8.0. Case Study Inset 3-1: Regulatory Driver for Periodic Assessments Sydney Water has an inspection program in which all assets are visually inspected and appropriately tested every five years. The five-year interval is a statutory requirement and was determined by the New South Wales Government (Australia). See Case Study 9 in Chapter 8.0. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 3-3

As well as being a useful metric with which to target condition assessment effort, the management of utility risk itself is an important driver behind undertaking condition assessment. In particular, third party risk associated with asset failure (such as property damage) may be unconnected with the importance of the asset itself, as illustrated in Case Study Inset 3-2. It is therefore important to characterize consequence in terms of business risk, considering issues such as third party damage and environmental impacts. Case Study 3-2: The use of Inspections to Manage Third Party Risk The City of Bellevue Council is very interested in reducing claims from property damage or business interruptions. This has increased focus on system performance and reliability. A risk-based leak detection program has therefore been underway for several years. High-risk pipes were identified by overlaying several property damage-related risk factors, including: properties where home elevations were below adjacent street levels, areas where older (pre- 1986) ductile iron water mains were installed and areas of high percolation soils (likely to transmit water rather than force it to the surface where it would be observed). Acoustic leak detection efforts have targeted areas with these three risk factors to prevent minor leaks from becoming major problems. City staff have also performed hydraulic and surface water modeling to determine areas of the system and hydraulic conditions that would cause the sewer hydraulic grade line to be above basement floor levels and thus where the City may be susceptible to property damage claims. Condition assessment and operations and maintenance activities are then prioritized accordingly. See Case Study 10 in Chapter 8.0. 3.3 Outputs from a Condition Assessment Program Before addressing the design of a condition assessment program in more detail, it is worthwhile to consider the outputs generally sought from condition assessment programs as applied in the water utility sector. When undertaking condition assessments, inspection data is collected through a number of tools and provides information on such things as the presence of defects and their severity. However, even when a defect such as a crack or corrosion is identified, the question still remains as to the significance of the findings. Data collected during inspection of assets must therefore be interpreted through appropriate analysis to give an assessment of condition in terms of the operating demands placed on the asset. Outputs of this process can be expressed in a variety of ways. For example, Engineering Calculations, Probability of Failure, Remaining Life Estimations and Condition and/or Performance Grades (ratings) are commonly used. Each of these approaches is discussed briefly below. 3.3.1 Engineering Calculations Engineering calculations can be used to interpret inspection data deterministically. In this approach, the results of a structural inspection (e.g., the presence of critical defects, remaining wall thickness, etc.) are used to calculate whether the asset still provides sufficient safety margins to comply with required standards and codes, considering both static and dynamic operational loads (e.g., calculating the loads applied to the remaining cross-sectional area of a 3-4

corroded structural member). Case Study Inset 3-3 gives an example of the use of condition assessment to determine the presence of critical defects, and the structural analysis subsequently undertaken to assess the propensity for asset failures. Case Study Inset 3-3: Remaining Life Calculations for a Sewer Water Care operates an 18 km long reinforced concrete interceptor sewer, cast in situ in sections of 30 feet (10 meters), and built between 1960 and 1965. Initial inspection of the asset was carried out under a program to determine the overall condition of all sewerage assets. The initial condition assessment used visual inspection techniques that determined the presence of defects. In some sections the concrete had corroded to the extent that the inner reinforcement bar of the pipe wall was showing. Collapse of these sections would lead to significant health, environmental and third party consequences. The presence of the defect was, however, only a relative indicator of condition. Preliminary structural analysis was undertaken to assess the risk of collapse in the sections subjected to significant levels of acid attack. The implication of this preliminary analysis was that there was a risk of collapse under certain conditions and on-going deterioration would increase the likelihood of failure. Early replacement of the asset was considered, but there was insufficient redundancy in the network to allow the asset to be replaced. Further inspection of the asset was undertaken to determine the rate of deterioration and the results of the inspections used in refined modeling studies to put the asset deterioration into context. The cost of the additional analysis was justified because of the high level of perceived risk and the lack of available options to manage that risk. An iterative approach to assessment was therefore justified on the basis of risk, in which more accurate (and expensive) techniques were used to refine the knowledge of an asset and give better support to decision making. See Case Studies 6 and 7 in Chapter 8.0. 3.3.2 Probability of Failure Estimations Given the discussion on asset risk presented in the last section, an ideal output for many purposes would be a direct measure of failure probability that accurately reflected the level of asset deterioration. In combination with load/capacity information and failure consequence assessments, condition assessment would then allow the utility to quantify risk. Given an understanding of risk, utilities are able to determine appropriate operational, renewals and other asset management strategies. The need to calculate probability of failure often arises because loading conditions are inherently uncertain; understanding load-capacity relationships is of central importance to the prediction of asset failure. From the perspective of condition assessment, however, the issue often being considered (implicitly or explicitly) is how the probability of failure is changing over time due to (say) reduction in structural capacity. In general, this information cannot be derived from a single condition assessment. Repeated measurements over time are required to calculate the rate at which conditions are reducing, and probability of failure increasing. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 3-5

Condition data collected over time can be used to produce deterioration (or decay) curves that allow the probability of asset failure to be modeled (see Case Study Inset 3-4 for an overview of such an approach). Such deterioration (or decay) curves can also be used to give an estimate of remaining life. Case Study Inset 3-4: Estimating Probability of Failure for Water Pipes There are principally two approaches used to determine the probability of failure of buried water pipelines: Statistical approaches based on analysis of available failure records. Physical probabilistic approaches derived from physical principles of pipeline failure combined with a stochastic representation of input variables. Physical probabilistic approaches can also be compared to and calibrated against available failure records data and can also use condition-monitoring data as input. In both approaches, various asset parameters are considered in the analysis, such as pipeline diameter, material type, installation year, etc., along with other risk factors such as operating pressure, soil type and soil ph. The outputs of failure probability predictions are of two main types: Failure rates for groups of pipes (i.e., statistical expectation of the number of failures per length of pipe). This is typically given in predicted failures per unit length per year. A probability density function for the time to first failure for a given pipe. See Case Studies 13 and 14 in Chapter 8.0. 3.3.3 Remaining Life Estimations In practice, it may be impractical or too costly to develop an assessment of failure probability with any reasonable degree of certainty. It is, however, possible to estimate the remaining service life with information on asset age, condition and knowledge of how the asset deteriorates over time (Newton & Vanier, 2006). With this approach, the purpose of asset condition assessment is to detect and quantify rates of degradation and to provide a measure of the existing condition of the asset. It is often more pragmatic to classify an asset in terms of condition and relate this to its remaining life, as in the example given in Case Study Inset 3-5. In this context, remaining life means the time left until the asset can no longer perform its primary function(s). 3-6

Case Study Inset 3-5: Remaining Life of Ferrous Pipes In the approach used by Scottish Water, the structural condition of ferrous water mains is determined via an estimation of remaining service life. Remaining service life is assessed using excavated sections of water main, which are shotblasted to remove the graphitized corrosion products. Remaining life is predicted from the derived corrosion rate (based on pit depths and age) in conjunction with the remaining pipe wall thickness. See Case Study 2 in Chapter 8.0. Realistic remaining life estimations are required if this approach is to be used in asset management. For mechanical and electrical assets, condition monitoring techniques (vibration monitoring, oil testing, and thermography) can be used to track deterioration rates and therefore estimate remaining life (condition monitoring in this context is discussed fully in Chapter 5.0). For pipeline assets especially, a reasonable understanding of the degradation and failure processes is required to define appropriate end of life criteria, as well as the expected life of assets and/or the implications of critical defects to remaining life. For pipeline assets, the identification of a defect does not in itself always given an indicator of asset remaining life. As illustrated in Case Study Insets 3-6 and 3-7, significant amounts of analysis may be needed to interpret the results of pipeline inspections. T understand remaining life fully, utilities also need to consider other reasons why an asset may need replacing, for example, when an asset is under-capacity, obsolete, under-utilized or too expensive to maintain. Performance standards and/or risk factors should also influence the age at which assets are considered due for replacement. Performance is not always directly related to condition, since assets can continue to perform their functions satisfactorily even when their condition has significantly deteriorated. Hence, expenditure priorities are often more effectively determined by assessing asset performance, rather than merely structural condition. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 3-7

Case Study Insets 3-6: Remaining Life Calculations for a Water Main CSIRO undertook a condition assessment of a 250 millimeter (mm) diameter cast iron water main on behalf of a client. The main was installed in the 1860 s and remained unlined until 1980 when it was cement lined in-situ. Five sections of pipe, each approximately one meter long, were exhumed by the water authority and assessed to determine the remaining wall thickness (in this case the defect under consideration was loss of metal due to corrosion). The raw data from residual wall thickness measurements was first used to derive a probability density function (PDF) for the corrosion rate. This PDF was then used in conjunction with a physical failure model to assess the propensity for asset failure. The failure model considered both the resistance of the CI pipe as it corroded and the applied service loads (including internal pressure, soil dead loads, and surface loads). The outputs of the modeling study were summarized in terms of a plot that shows the expected pipeline failure rate as the pipe ages. In combination with data on failure costs, this type of plot can be used to analyze remaining economic life. See Case Study 13 in Chapter 8.0. Case Study Inset 3-7: Remaining Life Calculations for a Sewer Force Main CSIRO undertook a condition assessment of a 300 mm AC pressure sewer pipe constructed in 1978 on behalf of a client. Soil testing was carried out at seven locations along the route of the pipeline to determine the soil aggressiveness (ph, soil characteristics). With this data, a preliminary analysis was carried out to identify sections with high probability of failure (hot spots). Several of the positions were recommended for core sampling of the AC pipe. Cores were taken and the residual tensile strength of the pipe wall assessed (in this case the defect under consideration was loss of wall strength due to material deterioration). The data on residual strength was used to derive a PDF that quantified the variation in deterioration rate for two distinct soil environments. This PDF was then used in conjunction with a physical failure model to assess the propensity for asset failure. The model considered both the resistance of an AC pipe as it ages and the applied service loads (including internal pressure, soil dead loads and surface loads). The outputs of the modeling study were summarized in terms of a plot that shows the expected time to first failure for various loading conditions. In combination with data on failure costs, this type of plot can be used to analyze remaining economic life. See Case Study 14 in Chapter 8.0. 3.3.3.1 Techniques for Establishing Remaining Service Life There are a number of techniques that can be used to establish the remaining service life of infrastructure assets: including testing of materials or components, factor methods, 3-8

deterministic (decay) curves, analytical models or probabilistic models (see Vanier & Rahman, 2004 for more details): Testing of materials or components offer the possibility of obtaining data that can be subsequently used in the development of models for service life prediction. The testing may include the gathering of data either from the periodic inspection of components or direct field measurements of performance indicators over months and years. Typically, short-term tests are carried out in a laboratory. Long-term studies may be undertaken in either laboratory or field conditions. The factor method is a weighted factor approach developed for use in management of building assets. A number of independent factors affecting service life (e.g., design, construction quality, load, maintenance level and material quality) are identified, evaluated and rated. The estimated service life is calculated by multiplying a predetermined reference service life by all of the weighted factors. Deterministic (decay) curves model the deterioration of assets. Curves can be developed for asset types either based on the use of expert opinion or historical asset failure data. Analytical models calculate the remaining service life by modeling the deterioration process itself. Probabilistic models attempt to account for the apparent randomness of the failure of components and systems through appropriate means, including Markov chain and Monte Carlo analysis. Utilities can also develop in-house systems for estimating the remaining life of assets based on operational experience. These can be combined with grading procedures, as illustrated in Case Study Inset 3-8. Such approaches are pragmatic, especially when there is insufficient data upon which to base quantitative assessments. However, the use of operational experience is subjective, can be influenced by recent problems and is not generally auditable. As such, while such approaches may be pragmatic in the short term, data collection systems would ideally be put in place to provide the data required for more quantitative assessments in the future. Case Study Inset 3-8: Estimating Remaining Life Using Operational Experience Sydney Water has extended the use of grading procedures (see Section 3.3.3) to allow an estimate of remaining life to be generated. Each asset is categorized into five grades by analyzing information from the following sources: 1. Planned maintenance and overhaul. 2. Feedback from operators and maintenance staff. Scores are given for a range of parameters, including consequence of failure and occurrence of failure. Occurrence of failure is developed using an annual failure rate. The scores for each of the grading systems are inputted into a formula that gives an estimate of the remaining life of each asset. Depreciation is determined as well as required maintenance and whether replacement or renewal of the asset is required. See Case Study 9 in Chapter 8.0. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 3-9

3.3.4 Grading/Rating Systems While desirable, assessing the probability of asset failure or specifying a meaningful remaining life can be challenging and difficult to benchmark. It is often more feasible to simply specify thresholds of condition and performance where interventions must occur, and identify if a given asset has reached that threshold. This approach is implicitly incorporated into the design of grading systems commonly used for strategic asset management purposes. Two types of grade are commonly applied: Condition grades are allocated through visual inspection of an asset and with reference to specified descriptions of each grade. Grading asset condition in this way gives a measure of the level of physical deterioration with respect to the as new condition. A condition grade can be allocated reliably only after explicit visual examination of the asset. Desktop assessments of an individual asset are less reliable. Various modelling approaches can, however, be used to allocate grades that are valid in a statistical sense (see for example Case Study 1 and 2 in Chapter 8.0). Performance grades give a broad categorization of an asset s ability to function in accordance with the utility s requirements and are allocated using operational knowledge of the asset, again with reference to specified descriptions of each grade. A performance grade can only be allocated reliably with reference to detailed local operational knowledge. Grading asset performance in this way gives a measure of asset performance with respect to local (asset-level) requirements. As noted in the International Infrastructure Management Manual (IPWEA, 2006), grading systems can be developed that are simple (Grade 1 to 5), intermediate (Grade 1 to 5 with subgrading for the worst three grades) and sophisticated (multi-faceted) ranking schemes, although these multi-faceted schemes can be reduced to 1 to 5 when necessary. The design of an effective grading system involves two stages: Asset observations that are deemed to be important to the condition or performance (as appropriate) of the asset type in question are first identified (see examples in Table 3-1). These asset observations are then mapped to a given grading system. With regards to the first point, it is possible to determine asset characteristics that reflect good or bad condition/performance for any asset type. These characteristics then form the basis of the grading system. For example, Table 3-1 presents asset observations that relate to the condition and performance of various categories of assets. Appendix C presents a more comprehensive list of asset characteristics used in grading systems for a range of representative asset types. 3-10

Assessment type Electrical Asset Condition Mechanical Asset Condition KEY: Table 3-1. Condition and Performance Assessment Criteria. Assessment criteria Electrically safe (O/M) Level and urgency of maintenance required (O) Visible wear and tear (V) Condition of insulation (V/M) Break downs and failure history (M) Maintenance costs (M) Health and safety issues (V/O) Serviceability (V/O/M) Soundness of unit; as new? (V) Level and urgency of maintenance required (O) Level of wear and tear (V) Condition of protective coatings (V/M) Corrosion (V/M) Break down and failure history (M) Maintenance costs (M) Serviceability (V/O/M) Health and safety issues (V/O) (V): Visual; an auditor would be able to evaluate the assessment criteria directly (visually). (O): Opinion based; the auditor would be able to evaluate the assessment criteria indirectly (by interview). (M): Measurable; the assessment criteria could be directly measured (inspected/monitored) or assessed through analysis of available operations/maintenance data. To illustrate the process of developing a grading system, it is informative to consider the design of sewer grading systems commonly used in many countries, including the United States, Australia and the United Kingdom. Structural condition of sewers is often assessed through closed circuit television (CCTV) inspection. A range of defects are evaluated in these inspections, including cracking, fractures, deformation, loss of fabric; including mortar loss, brick displacement, etc., joint/connection defects and loss of level. A grading system must incorporate consideration of these defects in a manner that reflects the various stages of asset deterioration. The grading of individual assets then informs asset management by summarizing asset condition and thus the requirement for some form of action. Grading approaches for sewers often use a scoring procedure in which defects are given a score corresponding to the severity of the defect and its potential impact on asset failure. Defects observed during the CCTV inspection are noted in a standard report, which can then be run through software to score the sewer lengths and provide an overall 1 to 5 grade. This grade summarizes the condition of a sewer length, generally from manhole to manhole. The 1 to 5 grades can also be allocated directly by the inspector. Table 3-2 shows a grading system that has been used by the Office of Water Services (Ofwat) in the United Kingdom, and is consistent with the grading system presented in the Water Research Centre (WRc) Sewer Rehabilitation Manual and other grade systems used in the United States and Australia. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 3-11

Condition grade Table 3-2. Ofwat PR99 Information Sewer Grading System (Ofwat, 1998). Description for brick sewers For other sewers 1 No structural defects. No structural defects. 2 Minor cracking or no deformation or loss of bricks and mortar loss confined to surface and line and level as built and connections satisfactory. 3 Deformation 0-5%, no fracture and only moderate mortar loss or displaced bricks or total mortar loss without other defects or occasional defective connections. 4 Deformation 5-10% and fractured or total mortar loss or small number of missing bricks or displaced/hanging brickwork or moderate loss of level or frequent badly made connections or dropped invert. Circumferential cracking or moderate joint defects. Deformation 0-5% and cracked or fractured or longitudinal/multiple cracking or occasional fractures or severe joint defects or minor loss of level or badly made connections. Deformation 5-10% and cracked or fractured or broken or serious loss of level. 5 Already collapsed or deformation >10% and fractured or extensive area of missing bricks and/or displaced/hanging brickwork or missing invert. Already collapsed or deformation >10% and cracked or fractured or broken or extensive areas of missing fabric. The general interpretation of grades used in Ofwat s regulatory reporting is consistent with the interpretation placed on sewer grades used in the United States (e.g., National Association of Sewer Service Companies or NASSCO grades) and Australasia. This interpretation is as follows: Grade 1: Asset as new. Grade 2: Asset showing initial signs of deterioration. Grade 3: Asset condition generally satisfactory (unless in an area of high risk, for example, sewer prone to surcharging or in running sand). Grade 4: Asset in poor condition; action needed soon (especially in an area of high risk, for example, sewer prone to surcharging or in running sand). Grade 5: Asset in need of urgent action. These (or similar) interpretations can be placed on all grade systems, although as noted previously there is no requirement for the grades to be based on a 1 to 5 system. For example, some legacy grading systems used were based on a 3-grade system, as indicated in Case Study Inset 3-9. 3-12

Case Study Inset 3-9: Legacy Grades used within MWRA Massachusetts Water Resources Authority (MWRA) has performed closed-circuit television (CCTV) inspection of its entire gravity sewer interceptor system, and used these data to assign condition grades to each pipeline segment. MWRA recently shifted to the NASSCO standard 1-5 rating system, but much of their historical condition data are still in a legacy A, B, C condition rating system. See Case Study 12 in Chapter 8. Condition and performance grades give a useful summary of structural condition and the priority for action. However, the results of the grading procedures should be interpreted with some care, as outlined in Case Study Inset 3-10. Case Study Inset 3-10: Interpreting Condition and Performance Grades With the 1 to 5 grade systems commonly used in the United Kingdom and other countries, it is reasonable to conclude that capital investment is required for any asset in condition grade (CG) 4/5 or performance grade (PG) 4/5. Given knowledge of the replacement value of an asset in these grade bands, a first pass assessment of the potential investment required can be made (however, this is likely to be a worse case assessment, as it assumes the whole asset needs to be replaced). However, some assets are in poor condition and perform badly (that is, are in both CG 4/5 and PG 4/5). When considering investment needs, the intersect between assets with both condition and performance grade 4/5 needs to be determined. For example, analysis undertaken by Scottish Water at the time of the assessment program detailed in Case Study 1, indicated the percent value of assets requiring investment was given by: 0.7 (% assets in PG 4/5 + % assets in CG 4/5) In practice, the amount of investment needed must be calculated using more refined analysis considering risk, service, alternative interventions and affordability issues. Nevertheless, the value of assets in condition and/or performance grade 4/5 is a simple metric of the state of the asset stock. 3.3.4.1 Granularity of Grading Non-pipeline assets are often represented as a hierarchy in asset management systems, from the facility level, through process stream, to individual units and their components (see Section 7.3 for more details on asset hierarchies). Condition and performance grading can be carried out at any level in this asset hierarchy, that is, grades can be allocated at the work, process, unit or component level. When determining at what granularity (level within the asset stock) to allocate grades, a trade off is made between the level of detail, cost of assessment and quality of decision support: High level assessments provide a coarse level of detail, quicker and cheaper assessment programs but poor discrimination (when assessing condition at a high level, the asset must be allocated a poor grade if any part of it needs rehabilitation or replacement), with relatively poor decision support. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 3-13

Lower level assessments provide a fine level of detail (grades are allocated at the unit or lower level), require more time consuming and expensive assessment programs, but provide better discrimination and decision support. 3.3.4.2 Recommended Approach to Grading Although grade systems give a useful summary of data collected in the assessment of an asset, the aggregation of asset observations into a single grade at the point of survey leads to a loss of information. As such, all observations/defects observed during a condition or performance assessment should ideally be recorded, with the combination of these observations into a single grade being made subsequently and away from the point of survey. When applied in practice, the accuracy and consistency of grading depends on the inspector s experience and the reliability of the grading system used. Auditing is therefore an important aspect of grading programs, as discussed in Case Study Inset 3-11. Case Study Inset 3-11: Auditing of Assessment Programs based on Grading In a condition and performance-grading program undertaken by Scottish Water, on going auditing and quality control (QC) checks were deemed essential for consistency purposes. Repeat audited surveys were carried out as part of the QC checks; current condition and performance grades had already been collected for units within selected works as part of the assessment program. The teams were then required to re-survey the works in the presence of an auditor. As such, two sets of separately collected current condition and performance grades were available for those works; one set collected independently and one collected in the presence of an auditor. Having two such sets of condition and performance data allowed the consistency of allocated grades to be assessed. Analysis of grades showed that the proportion of unacceptable grades (assessment of the same asset resulted in an allocation of grades differing by more than one grade) was about 1%. This definition of acceptability took into account the inherent variability of the grading process; a grade difference of one can be attributed to different interpretations of grade definitions and/or asset observations, and is considered acceptable. See Case Study 1 in Chapter 8.0. 3.3.4.3 Limitations of Grading Systems While useful, grading systems are often designed as screening tools, in which case additional information is required to support decision making and prioritization, including the analysis of risk and cost and the operational context of the asset. For example, in the case of sewers, reliance on structural condition grades alone is not recommended, but this practice does occur; utilities and their contractors often use internal condition grades (ICGs) in decision support for management of critical sewers. However, in the original WRc process, from which most if not all grade systems are derived, characterizing the ICG was just the first step in the assessment. The priority for action was then determined through consideration of other factors; the interpretation of a specific ICG would be modified by consideration of the type of soil and the risk of surcharging. Hence, a sewer with ICG of three in running sand and subject to surcharging, would be considered a higher risk and thus a higher priority than an ICG of four in clay soil with no surcharging. 3-14

The use of grade systems beyond their intended scope as initial screening tools may be understandable given the effort in collecting them, but the impacts of this practice on the effectiveness of decision support should be considered, since it may have implications on the utility s ability to optimize capital and operational expenditure. Limitations to the use of grading schemes when used in regulatory reporting are highlighted in Case Study Inset 3-12. Case Study Inset 3-12: Limitations of Grade Profiles as a Metric for Benchmarking As part of the regulatory reporting and planning cycles, the regulators in the United Kingdom required that companies summarize the state of the asset stock in terms of condition and performance grade profiles. Grade systems used by different utilities for above and below ground assets varied in the level of detail and the specifics of grade definitions. Hence, while the overall interpretation of grades 4 or 5 would be consistent (being indicative of assets requiring some investment), differences in the level of detail of the grading procedures used, as well as differences in the calculation of asset values meant that comparison with grade profiles produced was not a rigorous benchmark. Profiles of asset condition and performance grades do not therefore provide an appropriate benchmark for inter-company comparisons due to uncertainties introduced by differences in, for example: Grade definitions (including consideration of whether an asset s design/capacity is suitable in performance grades). Asset valuation techniques applied (assuming grade profiles are developed in terms of the value of assets in a given grade band). Granularity of analysis (grading systems were developed by different companies in the United Kingdom that were applied at the works level, process level and unit level). Comparable results are only obtained with consistent grade definitions and grading procedures, with grades allocated at the same level in the asset hierarchy. Calculation of asset value must also be done in a consistent manner. 3.4 Designing a Condition Assessment Program In reviewing current industry practices, a number of protocols for designing a condition assessment program were identified. Two of these are included in Case Study Insets 3-13 and 3-14. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 3-15

Case Study Inset 3-13 Infraguide s Protocol for an Integrated Approach to Assessment and Evaluation of Municipal Road Sewer and Water Networks Given the social costs associated with infrastructure renewal and the need to deliver better value, an integrated approach to the replacement of road, sewers and water systems is desirable. As such, NGSMI (2003) proposed a five-stage approach for the assessment and evaluation of these systems: Task 1: Compile a detailed asset inventory with physical attributes, and appropriate cross- referencing and geo-referencing (preferably using GIS). Task 2: Undertake investigations of components at a frequency related to condition and importance. Results of investigations should be documented to allow the rate of deterioration to be understood. Task 3: Undertake condition assessment using condition-rating systems based on performance indicators to identify and prioritize the renewal requirements. Some consideration should be given to capacity issues within the rating system. Task 4: Evaluate performance over a specified planning horizon (e.g., 20 years), projecting the investment required to maintain performance levels, considering both proactive and reactive maintenance expenditure and availability of budgets. Task 5: Develop a renewal plan using appropriate economic tools to identify appropriate interventions, taking into account socio-economic impacts, risk, capacity issues, changes in regulations and policies, adjacent infrastructure condition and emerging technologies. It was noted that these tasks are not necessarily distinct, nor do they have to be conducted sequentially. Condition rating (grading) systems are used to identify and prioritize the renewal requirements for roads, sewers and water mains. Several performance indicators (e.g., structural defects, capacity and asset importance) are used to assess asset structural condition and functional adequacy. The number of indicators used in the condition rating system will vary among municipalities, depending on the size of the municipality, the data available and the specific conditions of the system. The protocol indicates that all components of infrastructure should be assessed at a frequency that is shorter than half its expected life. The above protocol has also been applied specifically to the assessment and evaluation of storm and wastewater collection systems (see NGSMI, 2004). 3-16

Case Study Inset 3-14: Hydro One s Asset Condition Assessment Protocol This case study is drawn from Hydro One Networks' Applications to the Ontario Energy Board. Hydro One s asset condition assessment (ACA) protocol is as follows (after Hydro One 2005). Asset condition assessment information is routinely and consistently collected by Hydro One and updated to support decision processes. Since gathering detailed condition information on every individual asset is both practically and economically infeasible, Hydro One s distribution assets are grouped into 20 logical asset classes. These classes are prioritized into three categories, Priority 1 (P1), Priority 2 (P2) and Priority 3 (P3), based on the value of the asset class to the business. This in turn determines the importance of acquiring the condition information. The ACA process is outlined below: 1. Identify asset classes and demographics, and prioritize the asset classes (P1, P2, P3). 2. Define the asset information needed to determine and evaluate asset condition for all P1 and P2 asset classes, including asset condition and asset end-of-life criteria. 3. For all P1 and P2 asset classes, determine the additional condition information required to adequately assess asset condition. 4. Collect the necessary asset condition information from existing databases or through regular testing, surveys or inspections. The objective is to collect statistically relevant population samples of asset condition information, which will enable a condition assessment of the asset population in question. 5. Analyze the asset condition and performance information to identify population condition, performance trends and high risks and impacts of asset condition on meeting business objectives, including service quality standards. 6. Verify and confirm that the asset condition assessment results reflect actual field condition (spot audits). Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 3-17

Notwithstanding the value of these and other approaches identified in the research, given the range of asset management strategies currently being adopted within the water sector, a more generic approach to designing a program of condition assessment was deemed necessary. A 10- step approach was developed, drawing on the various protocols reviewed in the project (for examples, see the case study insets above). This approach is in line with the best practice concepts discussed in Chapter 2.0, and can be applied by utilities with a range of asset management sophistications, using different approaches to condition assessment across a range of asset types. The 10-steps are presented in Figure 3-2 and discussed in more detail below. Figure 3-2. A 10-Step Approach to Specifying a Condition Assessment Program. In addition to these 10 steps, documentation and reporting of the overall process, data and information collected must be implemented as an ongoing process. 3-18

3.4.1 Step 1: Document Drivers Various general drivers can be identified for undertaking condition/performance assessments and it is desirable that the utility explicitly states what these drivers are as part of the program design. As detailed in Appendix B, these can include the need to: Understand/forecast budgetary requirements. Spend budgets effectively. Meet regulatory reporting requirements. Refine asset financial valuation. Undertake risk management. Improve asset management approaches. Improve operation and maintenance (O&M) strategies. 3.4.2 Step 2: Specify Explicitly the Objectives of the Assessment Program It is important that the utility understands not only the drivers behind the assessments, but the objectives of the assessment program itself. In particular, it is important to determine from the outset how the results of the condition assessment (and/or data arising from the assessment) will be used in decision making. Once the general drivers are understood, it is useful to document what the objectives of the assessment program are, for example, see Case Study Inset 3-15. Case Study Inset 3-15: Water Care s Assessments of Sewerage Assets In 1999, Water Care identified that the condition of Auckland s trunk sewer assets were unknown and that, in some cases, the consequences of failure would be significant. Project condition assessment and risk determination (CARD) was implemented as a result. The stated project goals of CARD included: Developing an asset condition monitoring and performance assessment strategy, including data management, storage and analysis. Determining the condition of the identified high-risk pipelines and potential failure modes. Identifying and quantify the risks of failure and economic life of the high-risk pipelines. Identifying management and mitigation measures, including: Maintenance and repair activities. Rehabilitation needs. Replacement needs. Developing programs for ongoing monitoring and assessment of the high-risk pipelines. See Case Study 6 in Chapter 8.0. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 3-19

Where KPIs are used to inform asset management, there may be a specific objective to provide more information on a measured shortfall in a KPI. As noted previously, the relationship between a range of asset management objectives, the associated KPIs and condition or performance assessment is summarized in Appendix A. In summary, the objectives in undertaking an assessment program are to: Understand the structural condition of individual assets or groups of assets where this condition is not known (required for regulatory reporting, financial planning, asset stewardship, due diligence and/or to identify deficiencies and areas of potential weakness or concern). Understand the performance of individual assets or groups of assets where this is not known and/or assess the reasons for poor performance. Detect the progression of deterioration and/or assess remaining lives including collecting inspection data for use in deterioration models (for capital renewal planning and risk management). 3.4.3 Step 3: Identify the Asset Type to Assess Once the objectives of the program are clearly specified, the asset types that need to be assessed may be obvious. Where this is not the case, or where multiple drivers exist, the assessment program should be initially formulated in the context of all relevant asset types. For example, given water quality incidents in a supply zone, it might be necessary to assess the performance of treatment work assets, as well as assets involved in transmission and supply of treated water. At a later stage of the design process, it may be necessary to limit the asset types considered and focus in on those where condition assessment will deliver most benefit (see Chapter 4.0). 3.4.4 Step 4: Collate and Analyze Available Data Data are routinely generated for many asset types and where there are records this may be sufficient for the purposes of the condition and performance assessment; that is, the objective of the assessment could be met by collating and analyzing available data. Since it is potentially low cost relative to undertaking a program of asset inspection and environmental surveys, this approach is recommended as a precursor to undertaking a detailed assessment program. For assets that are managed proactively, condition and performance related data may already be available from previous surveys, either on utility systems or in paper records. If this is the case, the available data should be reviewed as a precursor to any inspection or survey work. Failure event data are more generally produced for low consequence (reactive) assets, to which a run-to-failure maintenance model is applied (see Chapter 5.0). The data may be available on corporate systems (e.g., maintenance management systems), but not analyzed in the manner required to understand asset condition or performance. Data of interest will vary according to asset type, but will include such data items as: Asset-related data (material, wall thickness, configuration, vintage, etc.). Site/installation factors (surface and traffic, bedding, depth). Environmental data (e.g., for water mains, quality of conveyed water, soil category, soil temp, soil ph, soil moisture content, soil resistivity). 3-20

Available asset condition and performance related data (from job management systems, opportunistic condition assessments, local knowledge, etc.). Previous assessments of risk and consequence of asset failure. Service conditions (environmental attributes; operating context). Operational and maintenance data (from maintenance management system). Failure data (type of failure, probable cause of failure). When assessing the data that could be used in this type of analysis, the utility must consider both the quantity of data and the quality of data. The collated data should be assessed according to specified confidence criteria, which can include some or all of the following aspects of data quality: Accuracy Are the available data reliable? Completeness What is the data coverage; are there any gaps? Currency Are the data sufficiently up to date? Consistency Is there any contradictory data or information? Compatibility Are the data produced on the same basis as other similar information? Credibility Does the data align with local knowledge or typical ranges of values? Analysis of suitable data should then be undertaken at an appropriate level of detail, as dictated by the objectives of the assessment program. Through this analysis of data, an initial assessment of system performance and asset condition can often be made. Gaps in data can also be identified and/or clarified, which can be subsequently filled through environmental surveys and asset inspections. This initial data collation and review is an approach widely undertaken by (or on behalf of) utilities that are in the process of developing formal asset management approaches, but that have an immediate driver imposed on them to undertake some form of condition assessment. Analysis of data can then be undertaken to provide summary statistics on the frequency, spatial and temporal distribution of (say) failure events, costs, etc. It should be emphasized that where corporate data systems do not exist, a significant amount of information will still be available in the form of operator knowledge. This can be collated through communication with operational and engineering staff, for example, in a workshop setting. Capturing this information can be a critical step in design of an effective assessment program. 3.4.5 Step 5: Determine What Assets to Inspect, if Any After review and analysis of available data, it should be clear whether there remains a gap in asset information, and thus whether or not assets will need to be inspected. If this is the case, the specific assets to inspect are often dictated by the objectives of the assessment program. For example, the objectives and/or outcomes of the initial data review (step four) may dictate those assets to inspect, for example, problem assets or assets related to problems in service provision. Where the assets to inspect are not obvious, some sort of sampling procedure is required. As noted in the International Infrastructure Management Manual (IPWEA, 2006), statistical samples can be designed with various approaches, including: Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 3-21

Sampling all assets. Concentrating on high risk/high consequence or representative assets only. Actuarial sample (statistically valid) using appropriate means of stratification. The type of asset being assessed has an influence on the sampling strategy adopted. Above ground assets can be accessed and assessed more readily, so comprehensive programs may be economic, though the benefits of the assessment must still be compared against the costs. The assessment of below ground assets is more expensive and often focuses on important assets that should not be allowed to fail. However, pipe sampling can also be driven by the need to understand condition across a network, which requires the utility obtain a reasonable sample. The number of samples taken is often based on affordability, rather than statistical, considerations (see Case Study 2 in Chapter 8.0 for an example). Generally, it is easier to undertake condition assessments of wastewater assets because of the open nature of the network; access can be readily gained through the many access points. If statistical samples are employed as part of the condition assessment program, the rationale and sampling methods must be documented. Methods will ideally be applied consistently over time, and any changes documented. 3.4.5.1 Stratified Sampling Schemes When the assessment program is undertaken to comply with financial or regulatory reporting requirements, statistical sampling can often be adopted because some of the information relating to the asset stock can be obtained from data for a relatively small number of assets (compared to the asset stock). In this approach, the asset stock is stratified according to appropriate criteria, a sample of assets randomly selected and data collected for the samples using a range of approaches according to the asset type. Case Study Inset 3-16 gives an example of this approach. Once collected, the data are analyzed and various techniques are used to determine the statistics of the sample and to extrapolate this to the asset stock. For example, standard statistical packages can be used to generate mathematical relationships that describe the probability that an asset with a given set of characteristics will be within a certain condition grade. With appropriate data for the rest of the asset stock, such relationships can then be used to give an assessment of the condition profile for an asset type (that is, results of the analysis of the sample can be extrapolated to the rest of the asset stock). Greater precision is achieved by more intensive sampling. Intensity of sampling can be considered to be the proportion of the assets sampled (by number or length) from a given population of assets (individual pipelines, pipe cohorts, systems or utility-wide). The objectives of the condition assessment program influence the precision required. For example, short-term planning to maximize the benefit from available budgets can involve intense inspection of part of the system, whereas long-term planning can be supported by less intensive inspection across the whole asset stock. Normally, the sample size is derived from two interrelated pieces of information: 1) the degree of uncertainty that can be accepted in the estimates, and 2) the unexplained variability in the statistical model. Higher levels of confidence require more data to be collected and analyzed. If the sample is small, the estimates will tend to be more uncertain. Complete certainty requires all the assets to be inspected. 3-22

Case Study 3-16: Sampling to Understand the State of an Asset Stock Profiles of condition and performance grade plotted against asset value (modern equivalent) provide a useful insight into the state of an asset stock. The overall (utility wide) condition and performance profile of the asset stock can be most accurately defined when there are sufficiently valid (current) grades for all the assets. For periodic reporting, this is likely to require reassessment of those assets where the grades are too old to be considered valid. Whilst having grades for all assets minimizes the uncertainty in the profiles generated, it requires a costly rolling assessment program to be undertaken such that each asset is periodically inspected to provide updated grades as the existing grades become invalid (the existing grades become too old compared to the life category of the asset in question). Conversely, a representative sample strategy allows the profiles to be produced at less cost, but with defined levels of uncertainty in the profiles generated. When Scottish Water used this approach, the asset stock (water and wastewater treatment works) was stratified according to a range of criteria that biased the sample to larger, more important works. Assets were then randomly selected. The overall sampling process can be summarized as follows: Sites were categorized according to the categories already used in regulatory reporting (categories based on service area waste/clean the treatment complexity used in the works and works size band). Existing (legacy) condition data were used to classify the sites into three bands with good, fair and poor overall condition. This allowed a bigger proportion of sites in poor condition to be selected with the aim of gaining better confidence in the estimates of asset value in condition grades four and five (since grades four and five imply immediate investment is needed, these grade bands are of most interest). Within each condition band, sites were ordered by category (treatment type), then size band and then geographical area. A systematic sample was chosen from each condition band; every nth site was selected, with n chosen to give a reasonable sample number from each band. An initial assessment of sample size was made by a statistical expert and, once the data was collected, the confidence limits for the predicted grade profiles estimated to determine if further data was required. See Case Study 1 in Chapter 8.0. The number of assets that must be assessed also depends on how prevalent a characteristic of concern is within the asset stock; if the characteristic (for example, poor condition) is common, then relatively fewer samples will be required than if the characteristic is rare. Since the prevalence of a characteristic of interest will not be known in advance, the design of a sampling program may need to be iterative. Expert judgment should be used to assess the initial sample size deemed appropriate. The data should then be collected and analyzed and the confidence (uncertainty) in the results assessed. If the results are considered too uncertain, further data must be collected. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 3-23

3.4.6 Step 6: Select Inspection Techniques The selection of an inspection technique must be made in terms of technical suitability given the asset type and objectives of the assessment program. For many strategic asset management purposes, the grading approach discussed previously is likely to provide satisfactory results. Where such an approach is not deemed appropriate, the tool selection procedure presented in Chapter 6.0 should be followed. Economic factors that influence affordability and cost of the program must also be considered, these are discussed in Chapter 4.0. 3.4.7 Step 7: Plan Program of Inspection to Minimize Cost A project plan should be drawn up that either: Minimizes the cost of undertaking the condition assessment program, or Maximizes the value derived from the assessments. Costs can be reduced by clustering activities to minimize travel time and other costs. Appropriate quality assurance procedures should be specified as part of the program plan, including appropriate levels of third-party auditing. 3.4.8 Step 8: Undertake Inspection and Data Collection The asset inspection may need to be augmented by additional data collection relating to the operating context and or relevant environmental factors. 3.4.9 Step 9: Analyze Data and Assess Asset Condition The raw data collected from individual inspections need to be analyzed to allow assessment of asset condition/performance. As far as is practicable, data should be analyzed as it becomes available as initial results can influence the way in which the rest of the program is undertaken, preventing wasted effort. As discussed in step five, data from a stratified sample may also need to be analyzed to give a view on the overall asset stock, if this is required. 3.4.10 Step 10: Utilize Condition Assessment Information for Decision Making The analysis undertaken in step nine is essentially the conversion of raw data into information that can be either reported or used in decision making. When it is to be used in decision making, the information is either implicitly or explicitly interpreted in risk management terms; that is, the condition and performance data are used to give an assessment of risk, place this assessment into context and determine interventions. Condition assessment or inspection does not in itself affect the likelihood of failure. Action must be taken in light of the assessed condition to repair or replace the assets (physical intervention), modify operational, maintenance, failure response, or inspection procedures (procedural changes), or address human factors (through increased supervision or training). These mitigation activities reduce the failure frequency and hence the risk. 3.5 Additional Implementation Issues As well as addressing the 10-step approach given above, a water utility embarking on a condition assessment program should also consider the following implementation issues. 3-24

3.5.1 Asset Specific Considerations The type of asset has an important bearing on the overall approach to the design of the assessment program. For example, Table 3-3 indicates approaches to assessment of condition and performance for a range of asset classes. Asset class Treatment works Pumping stations Sludge treatment Raw water intakes Sea outfalls Water storage Dams/impounding reservoirs Potable mains, raw water aqueducts Mains (non-potable) Communication pipes Water meters Sewers Sewage and sludge pumping mains Combined sewer overflows (CSO) and other sewer system structures Table 3-3. Approaches to Assessing Different Asset Types. Suitable approach Inspection of a representative sample (condition/performance grade assessment and collection of other attributes) and estimation of the overall grade profiles from that of the sample. Since service reservoirs have to be drained down for inspection and cleaning, the sample inspected each year is influenced by operational considerations. Inspection frequency may be dictated by statutory requirements. Assess condition and performance using: Material, year laid, ground types and similar information. Quality problems. History of leaks or bursts, valve failures, etc., if any. Leakage monitoring. Potential consequences of failures through network modeling or other risk assessment technique. Condition assessment/cut-out samples. Generally as for raw water aqueducts but less detail is needed as consequence of failure is lower. Assess problems by material, history of problems and possibly time period laid. Use metered customer data to assess potential problems; for example: Apparently stopped meters. Customers with anomalous low consumption. Meters that have passed unexpectedly high volumes of water. Assess condition and performance using: Material, year laid, ground types and similar information. CCTV inspection data. Potential consequences of failures (flow models, etc.). Drainage area studies. Statistical analysis of collapses or blockages. Assess condition and performance using: Material, year laid, ground types and similar information. History of leaks or bursts, valve failures, etc., if any. Potential consequences of failures. Inspect as part of drainage area (catchment) study program. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 3-25

As well as requiring different approaches to program design, the range of assets used in the delivery of service means a utility will in general also need to use a variety of tools in its condition assessment programs. For example, Case Study Inset 3-17 lists some of the condition assessment tools used by Massachusetts Water Resources Authority (MWRA). The full range of tools available for use by utilities is detailed in Chapter 7.0. Case Study Inset 3-17: Condition Assessment Tools used by MWRA MWRA use a range of condition assessment tools and techniques, including: Acoustic ultrasonic vibration tools. Ultrasonics for thickness determination. Thermography. Permanent condition monitoring (vibration and temperature monitoring for large equipment). Oil sampling. CCTV sewer interceptor inspection (closed circuit television inspection system and sonar scanner system). Portable acoustic pipeline leak detection equipment and continuous monitoring acoustic equipment. See Case Study 11 and 12 in Chapter 8.0 for details of how MWRA use these tools. 3.5.2 Consistency Requirements The collection of consistent condition and performance data facilitates analysis and interpretation and also allows preparation of deterioration curves that permit prediction of either the probability of failure or the remaining life of assets. It is important to develop formal assessment techniques that give repeatable and objective assessments and apply these consistently over time. Individual asset groups may have their own specific grading or assessment standards. 3.5.3 Frequency of Assessments The 10-step procedure previously presented does not consider the frequency of inspection over time. Assessment frequencies may be based on individual asset management drivers. For example, GASB 34 requires that condition assessments be undertaken every three years. For assets of high failure consequence, it may be necessary to provide continuous monitoring or to undertake inspections at specified intervals. The concepts of risk-based inspection can also be used to specify a variable interval; that is, the time to the next inspection can be set given the results of a current assessment of condition, and with knowledge of deterioration mechanisms, failure modes and asset risk. This approach is considered in more detail in Chapter 5.0. Condition monitoring can also be used in the context of asset systems. In this case, condition monitoring is essentially periodic condition assessments undertaken to determine the overall condition of the asset stock, usually for regulatory/financial reporting or to monitor asset stewardship. Sampling can be used to determine what assets to inspect at any one time, or a 3-26

rolling program of inspection used to ensure that all assets are eventually assessed as part of the condition monitoring program, as detailed in Case Study Inset 3-18. Case Study Inset 3-18: A Rolling Program of Condition Assessments Water Corporation has undertaken a rolling program of condition assessment of all infrastructure assets, excluding water and wastewater collection system assets, under a program termed Asset Condition Assessment (ACA). There are 86,000 assessable elements in the program, covering most the asset types. These include, water and sewer pipes, valves, pumps, motors, tanks and reservoirs, including the roof, storage structure, appurtenances and buildings. Once fully implemented it is anticipated that the program will require approximately 6,000 assessments to be undertaken each year. See Case Study 3 in Chapter 8.0. 3.6 Documentation and Reporting On-going documentation and reporting of condition assessments and inspection findings is required if the information collected is to be utilized effectively, and to ensure traceability and transparency of approach. Information must be documented at both the program level and for individual assessments/inspections at the asset level. At the asset level, it is useful to record information on a data collection form. The form can be either paper-based or electronic (i.e., held on the inspector s laptop, palm top or similar computer device). Paper-based forms require little investment to implement, but the data must eventually be transferred onto corporate systems if it is to be used for anything other than just a record of the inspection. This inputting of data can be an expensive on-going task for large inspection programs. Electronic forms are more expensive to implement, since they require appropriate hardware and software, and need more investment in their design and development. However, design features like pick lists and drop-down menus can be implemented to guide data collection and help maintain data quality. The use of electronic forms also avoids errors associated with the transfer of data from paper records into corporate systems. Whichever approach is used in its design, the form should guide the inspection and facilitate the inspector to collect relevant information, including: Asset information (name, type, location, asset-reference number, etc.). Inspection information (inspector, date, need for follow-up inspection etc.). Condition information (e.g., grade score and condition observations). Information on performance (e.g., grade score and performance observations). Any corrective action required and the priority for the action. Appendix D gives an example of a paper-based form for condition assessment of mechanical and electrical (M&E) assets. This form was designed for the Industrial Assets Management Group within the Washington Suburban Sanitary Commission. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 3-27

Summary information is also required at the program level, so the specific information required for decision making must also be extracted and presented in a manner useful to decision makers. Decision makers are more often interested in the implications of the assessment, rather than the details of the assessment process and inspection results. In this context, effective reporting and communication requires that assessment results be contextualized and provided in sufficient detail to support the recommended actions, and no more. Summary approaches such as the use of traffic light systems (green for asset in satisfactory condition, amber for asset deteriorating, but OK and red for asset requiring immediate attention ) can be useful in management reports. 3-28

CHAPTER 4.0 Chapter Highlights JUSTIFYING A CONDITION AND PERFORMANCE ASSESSMENT PROGRAM There are numerous direct and indirect benefits to be weighed against program costs to justify condition and performance programs. Key benefits relate to enhanced understanding of asset-related risks and improved determination of the cost-effective time frame for asset renewal to avoid costly asset failures. Direct benefits of undertaking condition and performance assessment can include: capital deferment, budget justification, investment program prioritization, improved asset failure forecasting and in some cases, facilitated regulatory reporting. Indirect benefits can include extension of asset life, reduction in risk management costs, management of life cycle costs, improved productivity and efficiency, improved utility image and staff morale, improved levels of service and improved financial valuation and transparency. The costs associated with condition and performance programs can vary greatly depending on a utility s current state of program and tool development, and the current training levels of its staff. Program-specific costs also vary depending on the frequency of asset inspection prescribed and the number of assets to be inspected. While benefits are typically more difficult to quantify than costs associated with assessment programs, several methods for quantifying benefits are outlined, including: improved operations and maintenance efficiencies, catastrophic failure avoidance and improved service levels and program efficiencies. The ideal balance of assessment program cost versus certainty of information for decision making purposes are different for each utility, depending on the real or perceived asset risks, preferences for performance and risk avoidance, customer and political demands and the financial resources and liabilities of the utility. While it is acknowledged that an economic analysis is the ideal approach to justification, many utilities do not carry out explicit cost-benefit analysis because many of the programs undertaken are driven by a perceived need or are undertaken in response to explicit regulatory requirements. The justification process is often driven more by affordability and cost-effectiveness issues than explicit consideration of cost-benefits. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 4-1

4.1 Introduction Condition and performance assessment programs provide many benefits, but can also be expensive and time-consuming activities. Ideally, the expenditure on assessment programs should be balanced against the anticipated benefits. This requires that the cost and benefits associated with the programs be identified and evaluated in some way. This chapter highlights the key cost and benefits of condition and performance assessment programs and presents the steps that can be undertaken to justify these programs through economic analysis, including potential methodologies for estimating program benefits. Many of the benefits accrued are, however, indirect and/or intangible and thus difficult to quantify. Furthermore, while the direct costs associated with the assessments are readily determined, the indirect costs associated with setting up the necessary asset management systems may not be. The economic value of undertaking condition assessment programs within the context of asset management systems may therefore be difficult to estimate. Perhaps for these reasons, it was noted during this research that many of the utilities contacted did not claim to carry out explicit cost benefit analysis to justify their assessment programs. Assessments were instead commonly undertaken within the context of available budgets and the justification process driven more by due diligence, the need to understand performance issues, and/or affordability and cost-effectiveness considerations, rather than explicit cost-benefit analysis. These issues are considered in more detail in this chapter. 4.2 Key Benefits of Condition and Performance Assessment Programs One of the key benefits of condition and performance assessment is that it allows utilities to understand risk and determine when to intervene in the deterioration process to avoid failures that impose unacceptable costs or consequences (social, environmental or economic). However, as noted in Chapter 3.0, assessment of an asset in and of itself does not generate any of the benefits associated with risk reduction. It is only when an intervention is undertaken that reduces the probability of asset failure that a benefit is actually realized. The benefit is then proportional to both the reduction in probability of failure and the expected consequence of that failure. Where no action is taken, for example, where the asset is shown to be in reasonable condition, it may be tempting to consider the assessment as wasted effort accruing no benefit. However, in many cases the knowledge gained can be applied in a wider context (to other assets). In such cases, the improved knowledge of the asset base can be considered an intangible benefit. The magnitude of the benefits derived from any new assessment programs will depend on the actual current physical state of the existing assets (probability of failure), the failure consequences associated with assets and the value derived from the enhanced level of information that is gathered beyond that already available. Since asset management is reliant on asset information, the improved knowledge of assets also yields a range of asset management benefits. Table 4-1 details many of the benefits associated with condition assessment programs. The benefits are categorized as either direct or indirect. For the purposes of this discussion, direct benefits are considered to arise directly from the condition assessment itself. As such, these benefits would not be realized if the assessments were not undertaken. Indirect benefits are considered to be those benefits that are facilitated by an effective assessment program, but rely heavily on other business processes or are realized only after an intervention has occurred. This categorization is used simply to highlight the fact that condition and performance assessments are usually a feed into decision making and/or some other action, rather than being an end in and of themselves. 4-2

Category of benefit Direct Indirect Table 4-1. Benefits of Undertaking Condition/Performance Assessment. Benefit Capital deferment. Budget setting and/or justification. Capital works prioritization. Data that can be used in the production of deterioration curves (for some asset types). Ability to predict probability of failures. Demonstration of asset stewardship and the ability to adopt more favorable financial reporting approaches (modified GASB 34). Extension of asset life (when subsequent work is undertaken following the assessment). Reduced risk-cost associated with reduction in unanticipated asset failure (including avoidance of social and environmental impacts). Better management of life cycle costs and more effective capital planning and budgeting. Improved productivity, efficiency and effectiveness. Improved morale. Improved availability of assets and levels of service. Improved financial analysis. 4.2.1 Direct Benefits As noted above, direct benefits are considered to be those benefits that are not realized if the assessments are not undertaken. As shown in Table 4-1, these include: Capital deferment: undertaking condition and performance assessments can provide information on an asset that allows renewal to be deferred. This provides additional financial benefits, for example, increasing available budgets and thus potentially improving the affordability of other projects. Prioritization of capital program investments: accurate asset condition and performance data enables effective prioritization of capital investments and scheduling of projects according to actual needs. Improved asset failure forecasting: with extensive data on asset condition and tracking of asset failures, decay curves can be generated for certain asset types to better understand and forecast the timing of asset failures. Regulatory reporting: condition assessments allow utilities to demonstrate effective stewardship of their asset base. The use of condition assessments in this way forms the basis of the GASB 34 modified approach, referred to in Chapter 3.0. 4.2.2 Indirect Benefits Indirect benefits are those benefits that are facilitated by an effective assessment program, but rely heavily on other business processes or are realized only after an intervention (maintenance, replacement, change in operation, etc.) has occurred. As shown in Table 4-1, these include: Extension of asset life: asset life can be extended with appropriate monitoring and timely proactive maintenance efforts. Reduction in risk costs: condition assessment and performance monitoring programs that target the highest risk assets help to mitigate the occurrence of catastrophic asset failures. A systematic, risk-based program for monitoring and proactive management will also reduce overall utility risk, including liability for unforeseen damages. Management of life cycle costs: appropriate investments in understanding asset condition and performance can reduce overall life cycle costs by, for example, avoiding costly failures and reducing costly reactive maintenance requirements. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 4-3

Improved productivity and efficiency: in a similar vein, an effective assessment program takes much of the guesswork out of asset repair efforts, leading to more efficient and productive rehabilitation programs and improved overall economic efficiency of the utility. Improved utility image and staff morale: with improved asset condition and performance understanding, staff members have a higher level of confidence in the cost-efficiencies and service delivery of their programs. Improved levels of service: with better understanding of asset condition and performance, appropriate measures can be taken to promote higher reliability of operation and improved delivery of services to the customer. Improved financial valuation and transparency: more accurate and transparent asset valuations are possible with improved data on asset condition and actual historical useful lives of assets. The utility will also be able to present more transparent and defensible justifications to its board members and customers. 4.3 Key Cost Elements for Effective Condition Assessment Programs As with most activities undertaken by utilities, condition and performance assessment programs have a range of fixed and variable costs associated with them. As shown in Table 4-2, these include costs associated with both the collection and analysis of the data. There is also a component related to the number of assets inspected and the frequency of that inspection over time. These factors are a major consideration in the development of sampling programs. Category Fixed costs Time variable Spatial variable Other variable Reliability variable costs Table 4-2. Cost Elements. Cost element Procedure development IT system development Tools costs (license and maintenance) Cost of implementation Frequency of asset inspection Number of assets inspected Access costs Training Analysis and interpretation Reporting Maintenance of tools, etc. Cost of unnecessary intervention or incurred failures With regard to the last category in Table 4-2, since many condition assessments and inspections are undertaken to determine the need for action, the cost implications of assessment reliability should also be considered in the justification process. In this context, assessment reliability is taken to be any unnecessary cost incurred as a result of imperfect information generated by the assessment. As discussed further in U.S. EPA (2005), such reliability costs occur when: 4-4 A condition assessment indicated that an intervention was required, when in reality it was not; or Asset failure costs are incurred because a condition assessment indicated an intervention was not required, when in fact it was. The first issue is particularly problematic when undertaking interventions for buried pipeline assets based on the evidence provided by a limited sample; for example, when a pipe asset is

programmed for replacement because of poor condition, but only a small section of the asset was inspected. The occurrence of such an error might only become apparent during the rehabilitation process, which will incur some expense at least. Reliability costs are minimized by the use of either inspecting more of the asset (or assets), more accurate tools or analytical approaches during the inspection and assessment process. However, the result of this is higher condition assessment costs, so these two conflicting cost drivers must be traded off against each other, depending on the requirements of the assessment program. In addition to the cost elements shown in Table 4-2, the costs of assessment programs undertaken in the context of formal asset management also include a proportion of the costs associated with the design and implementation of the asset management and other business systems required to undertake strategic planning. Such costs include identification and collation of the necessary data, data management systems, software tools and procedures. This up-front investment is needed to maximize the impact of the condition assessment efforts and to utilize the information within the utility s strategic asset management systems. To the knowledge of the researchers, however, there is little evidence that utilities formally justify the investment in these and other improved asset management capabilities. Given the increasingly wide acceptance of asset management as a business philosophy, it can be inferred that there is an assumption that this investment will yield staff efficiencies, more consistent data, and that the overall asset management effort will result in the desired utility benefits. As such, the decision to go forward with the development of business systems is likely to be undertaken as a strategic management decision, based on the assumption that there will be an overall net benefit, rather than any detailed cost-benefit justification. There is, however, an increasing body of evidence throughout the sector to show that the investment in asset management sophistication and other business systems allows utilities to deliver improved levels of service to customers and the environment with reduced operational and capital budgets. For example, the privatized United Kingdom companies have delivered significant operational and capital efficiency savings, while meeting increasingly stringent standards associated with European Union regulations relating to the environment and water quality issues. Similarly, see Case Study Inset 4-1, which relates to the efficiencies realized by Scottish Water since its formation in April 2002. Case Study Inset 4-1: Scottish Water s Improvement in Efficiency Scottish Water has reduced operational expenditure by 150million per year (from 380million per year expenditure in 2002) and is delivering higher standards with around 1billion removed from the capital program. Much of the saving is associated with the ability to do more with less through better targeting of problem assets and/or necessary interventions. This has been greatly facilitated through the improvements in data and a better understanding of the condition and performance of the asset stock. These improvements have come at a cost, however, with 100million being invested in IT systems to provide a single asset management system across Scotland, and with an additional 200million being invested in the transformation process required to integrate the three former Authorities into Scottish Water. However, as noted above this has resulted in yearly saving of 150million in Opex alone. (Figures quoted are approximate and as related in the case study interviews; see Auditor General 2005 and references referred to therein for more details). See Case Studies 1 and 2 in Chapter 8.0. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 4-5

4.4 Economic Justification An economic justification of a condition and/or performance assessment program involves three steps: Step 1. Estimate (and quantify, to the extent practicable) the direct and indirect benefits of several potential condition assessment program options (including the no action option). Step 2. Estimate the costs associated with each program option (including cost elements such as equipment, training, inspections and management). Step 3. Calculate the net benefits (in dollars) and benefit/cost ratio associated with each option to help in ranking and potential program efforts. 4.4.1 Estimating Costs For the most part, utility staff and managers are well versed in the methodologies for estimating program costs, including labor, equipment, consumables, software, training and assorted fees. As such, this issue will not be considered in detail herein. 4.4.2 Quantifying the Benefits of Condition Assessment Programs In general, there are some direct and easily quantifiable benefits realized by an effective condition assessment program. These often take the form of cost savings or deferred spend. For the most part, however, this represents only a fraction of the overall benefits accrued by the utility. The total expected benefits realized by condition assessment programs are more difficult to quantify, since many are indirect or intangible in nature. Examples of methods to quantify different types of program benefits in support of a business case to undertake a condition assessment program are outlined below. Improved Operations and Maintenance Efficiencies. Benefits such as reduced energy costs or avoided/deferred maintenance expenditures (e.g., capital renewal; oil changes on major equipment) can be estimated directly, as can anticipated improvements in equipment availability and reliability. For example, the cost differential between a proactive maintenance effort (with all spare parts on hand and purchased without rush charges) and a reactive, emergency repair (potentially with overtime labor costs) can be quantified as a benefit. Catastrophic Failure Avoidance. These benefits can be quantified by calculating the potential cost and probability of occurrence of a major asset failure. Costs incurred might include emergency repair, permit violations and fees, liability and legal costs and reduced public trust. The benefit can be quantified as the reduction in risk cost (due to reduced probability of occurrence) with an effective risk-based condition assessment program in place. For example, if the potential consequences of a catastrophic event (e.g., failure of large sewer interceptor next to a sensitive water body) are estimated to be in excess of US$5 million, and the probability of this occurring in a given year is reduced from a 2% chance to a 1% chance due to proactive condition assessment efforts that trigger necessary maintenance activities or other interventions, then the reduced risk cost (benefit) can be estimated at US$50,000 ($5 million consequence) x (2% probability) ($5 million x 1%) = $50,000 benefit. For many utility managers, the indirect consequences (such as job losses) associated with this type of scenario helps justify the cost of condition assessment efforts. However, by their very nature, it is difficult to assign a monetary value to such consequences. 4-6

Improved Program Efficiencies. Another approach to quantifying benefits is presented in the International Infrastructure Management Manual (IPWEA, 2006), where the program budget (costs) multiplied by the anticipated improvement percentage is used to develop a quantified benefit estimate. For example, if a utility has an annual sewer inspection and maintenance budget of US$5 million, and risk-based screening efforts (i.e., better determination of the critical assets to inspect) and targeted condition assessment efforts (using the right tools to get data that will directly improve decision making) are anticipated to improve the efficiency and effectiveness of this program by roughly five percent, then the annual benefit could be quantified as: US$5 million x 0.05 = US$250,000. 4.5 Other Approaches to Justification While it is acknowledged that an economic analysis is the ideal approach to justification, as noted earlier in this chapter, during the research it was determined that many utilities do not carry out explicit cost-benefit analysis in justifying assessment programs. This is because many of the programs undertaken are driven by some perceived need and/or due diligence requirements. Similarly, other programs are undertaken in response to an explicit requirement, such as the need to report condition to a regulator or other statutory body, or to provide evidence in support of a proposed asset replacement program. In these cases, justifications are often undertaken within the context of available budgets. The justification process is driven more by affordability and cost-effectiveness issues than explicit cost-benefit analysis. Nevertheless, it is still considered important for utilities to put together a business case for the assessment program. In this approach, the perceived or actual need for undertaking the condition assessment is outlined, along with any anticipated benefits (not necessarily in monetary terms), along with an estimate of costs involved. This provides management with the information necessary to determine whether or not the proposed assessment program is necessary and viable. 4.6 Optimizing Cost and Benefits Associated with Assessment Programs As noted in the previous sections, any expenditure on assessment programs should be balanced against the benefits realized. Since these benefits are difficult to quantify, in practice, the degree to which condition assessment is carried out is often a strategic management decision. This has been demonstrated in a survey of asset management practices undertaken on behalf of the Office of Gas and Electricity Markets (Ofgem), a utility regulator in the United Kingdom. This survey found that there was a range of approaches to the definition, collection and recording of asset condition information. Some utilities routinely collected and acted on condition information, while other utilities considered that the effort involved in doing this produced insufficient benefits for long-term stewardship and thus did not adopt this approach (see Ofgem, 2002). There are, however, implications related to the amount of condition and performance data collected. At one extreme, data collected is insufficient to support effective asset management. At the opposite extreme, too much assessment effort is focused on assets where no significant risks are present, thus leading to an inappropriate allocation of utility resources. A balance somewhere between these two extremes is required, but the ideal balance is different for each utility depending on the real or perceived asset risks, preferences for performance and risk avoidance, customer and political demands and the financial resources and liabilities of the utility. Given that there is no set practice for determining the extent of condition assessment, it is important that the utility design assessment programs to obtain the outputs needed for its particular Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 4-7

asset management approach. In effect, this is the same argument presented in Figure 2-3, which illustrates that a utility should consider its information needs before determining what asset-related data it should collect. It is also important to note that, in practice, a utility cannot explicitly determine whether or not the ideal balance between assessment costs and other business metrics has been achieved. However, by following the step-wise methodology outlined in Chapter 3.0, a utility can continuously move towards the most appropriate investment level and maximize its potential for a cost-effective program by: Understanding its drivers and objectives. Defining the critical information gaps that are affecting decision making. Limiting condition assessment efforts to those steps necessary to filling the critical information gaps for enhanced decision making. Selecting appropriate tools and techniques that are fit for the purpose. Establishing the appropriate supporting people, processes and data management infrastructure to effectively analyze and continuously benefit from the assessment data captured. 4-8

CHAPTER 5.0 CONDITION ASSESSMENT AS A MAINTENANCE MANAGEMENT TOOL Chapter Highlights Effective maintenance practices help to minimize the whole life cost of asset ownership. The maintenance strategy (reactive or proactive) applied to an asset should depend on the importance of that asset to the utility s business objectives and the role the asset plays in service delivery. Condition monitoring is applicable as a proactive maintenance task when the benefits of undertaking the monitoring outweigh any avoided costs. Development of an effective condition monitoring program is centered on knowing when, where and how to inspect different asset types. These programs should be geared towards the stages of failure of individual asset types. Performance assessment also has a role as a condition monitoring technique. Observed changes in operational variables such as pressure, temperature, power consumption and/or asset capacity can indicate the on-set of failure. Several risk-based approaches, including reliability-centered maintenance (RCM) and riskbased inspection (RBI), are available to help utilities develop cost-effective maintenance strategies and determine those assets that should be managed reactively and proactively. A generic approach to specifying condition monitoring tasks is offered, including the following steps: Characterize asset importance. Assess failure modes and significance. Identify potential performance monitoring approaches. o Identify measurable parameters. o Determine performance thresholds. o Identify potential tests or monitoring approaches. Identify potential condition inspection approaches. o Identify degradation mechanisms. o Determine critical defects. o Identify potential inspection techniques. Select appropriate condition and performance assessment approaches based on cost, benefit and risk. A case study is also presented to illustrate how a water utility went about changing its condition monitoring practices in order to increase the amount of condition-based maintenance being undertaken. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 5-1

5.1 Introduction Utilities are tasked with supplying critical water and wastewater services to communities and the environment. From this perspective, a utility s business drivers are to provide sustained service delivery at an acceptable cost and in line with regulatory requirements, such as the need to maintain water and environmental quality and give due regard to public health and safety. The ability to deliver these services depends strongly on the business capabilities of the water utility (i.e., the people, processes, data and technology used within the business) and asset capabilities (i.e., the capacity, condition and performance of individual assets and systems). The concept that service levels are dictated by the utility s business drivers but underpinned by business and asset capabilities is illustrated in Figure 5-1 (this figure is also used in Chapter 2.0 and repeated here for the reader s convenience given the difference in target audience of the chapters). For example, business drivers such as customer expectations and requirements of regulators dictate the level of service that must be delivered, whereas asset and business capabilities impose a limit on the level of service that can be sustained over the long term. Where there is a disparity between the demand for service and the capacity to deliver that service, investment is required in the utility s asset and/or business capabilities. 5-2 Figure 5-1. Business Drivers and Utility Capabilities. In any asset-intensive sector, asset capabilities are a key component of service delivery. Effective maintenance practices help to preserve asset capabilities and in turn underpin the delivery of service over the short to medium term. However, as discussed in the Chapter 2.0, strategic asset management approaches and other business capabilities are also required to sustain the service provision over the medium to long term. Vanier (2000) noted that asset maintenance generally consists of: 1) inspections that are carried out periodically to monitor and record how systems are performing, 2) preventive maintenance that ensures that systems or components will continue to perform their intended functions throughout their service life, 3) repairs that are required when defects occur and unplanned intervention is required, 4) rehabilitation that replaces one major component of a system when it fails at the end of its service life and 5) capital renewal that replaces a system because of economic, obsolescence, modernization or compatibility issues. Approaches used in the specification of maintenance strategies are outlined in this chapter; including the role that categorization of assets plays in determining whether a proactive

maintenance strategy should be adopted. The role that condition monitoring plays in proactive management strategies is then discussed, including the concepts underlying P-F curves and the role of asset inspection and performance monitoring. Risk-based assessment procedures are then discussed, including reliability-centered maintenance (RCM) and risk-based inspection (RBI). A generic approach to the specification of condition monitoring tasks is then presented, which draws on the issues raised throughout the chapter. 5.2 Approaches to Maintenance Effective maintenance practices help to minimize the whole life cost of asset ownership. De Sitter s Law of Fives (De Sitter 1984, referred to in Vanier 2000 & 2001) approximates this effect: if maintenance is not performed, then repairs equaling five times the maintenance costs are required. In turn, if the repairs are not carried out, then renewal expenses can reach five times the repair costs. As will be discussed later in this chapter, the use of risk concepts in the development of maintenance programs can also help to manage whole life costs by reducing the frequency of significant failures and minimizing the impact of those asset failures that do occur. The U.S. EPA (2002a) identifies two different approaches to maintenance: 1) the asset management model and 2) the run-to-failure management model. In the asset management model, components of assets are regularly maintained and finally replaced when deterioration outweighs the benefit of further maintenance. Costs are well distributed over the life of the asset. In contrast, in the run-to-failure management model, assets are not regularly maintained, and can deteriorate faster than expected and led to higher replacement and emergency response costs. While the treatment given in the U.S. EPA (2002a) applies explicitly to sewer network management, this categorization is broadly applicable to maintenance for all buried assets. The categorization can also be applied to above ground assets with the proviso that routine maintenance tasks should in general be carried out in line with equipment manufacturer s recommendations and/or industry standards, as appropriate, to prolong the life of an asset and minimize the cost of asset ownership. The asset management model requires that planned maintenance tasks (i.e., maintenance tasks that are scheduled in some way rather than being carried out in response to asset failures) be carried out in an effective manner and in particular requires that proactive maintenance tasks be undertaken when justified. Proactive maintenance tasks are, by definition, carried out to: Prevent failures before they occur; or Detect the onset of failures (or occurrence of hidden failures) before they have an impact on the performance of the system. In practice, utilities have far too many assets to carry out proactive maintenance on them all, or at least any attempt to do so would be uneconomic. Even within the asset management model of asset maintenance given above, a run-to-failure strategy should be applied to assets when applicable. This approach will certainly apply to many pipeline assets of small diameter. However, this strategy should not be the default maintenance philosophy. Instead, the level of maintenance applied to an asset should depend on the importance of that asset to the utility s business objectives and, by inference, the role the asset plays in service delivery. 5.2.1 Proactive and Reactive Assets While proactive maintenance might seem the most effective approach to the management of assets, the cost of undertaking preventive maintenance is only justified where it helps to reduce the whole life cost of asset ownership (e.g., by extending service life or avoiding failures) or avoids unacceptable impacts. In light of this, an appropriate asset categorization scheme is one in which Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 5-3

assets are divided into proactive and reactive assets based on the different maintenance practices applied. As discussed in Buckland (2000), the term reactive asset refers to assets with a low consequence of failure (see Figure 3-1 in Chapter 3.0). Since the impact of failure is low, with the exception of any routine preventative maintenance tasks such as lubrication, etc., the assets can generally be left to operate until failure. Once failed, a decision is made whether or not to replace the asset. Such a decision would include consideration of the economics of continuing to operate the existing asset (including the social impacts of ongoing failures), the levels of customer service needed and operational strategies that could be economically implemented to reduce the impact of retaining the failing asset. It is interesting to note that the condition of reactive assets can often be predicted using statistical methods, because significant quantities of failure data are available. As the consequence of failure increases, the assets may still be operated to failure, but many utilities would prefer to take some failure prevention measures, providing they are economically justifiable. At a certain level of consequence though, it becomes necessary to use proactive maintenance strategies, including condition assessment or monitoring, to manage the probability of failure. Active protection techniques such as cathodic protection may also be applied to mitigate degradation for some asset types. While proactive strategies tend to be more justifiable at the high consequence end of the spectrum, they may also apply to lower consequence assets if the economics of this are favorable, for example, if low-cost condition assessment is available. In theory at least, the converse is also true for reactive strategies, whereby even though the consequence of failure of an asset may be high, if the cost of failure prevention is prohibitive, that asset may be operated to failure. However, in practice it is anticipated that utilities would use other strategies, such as redesign of assets or reconfiguration of networks, to manage such risks. 5.3 The Role of Condition Monitoring in Proactive Maintenance A key requirement for the implementation of proactive maintenance is the ability to anticipate when a failure will occur. Inspection of condition and monitoring of asset performance either by manual or automated means plays a significant role in proactive maintenance. 5.3.1 Asset Inspections Inspection programs are established to detect and evaluate deterioration of assets due to inservice operation. The tools and techniques, frequency and acceptance criteria used in the inspections can significantly influence the probability of component failure. Development of an effective inspection program is thus centered on knowing when, where and how to inspect. If evidence can be found that an asset is in a state that will eventually lead to a functional failure, it may be possible to take action to prevent it from failing completely and/or avoid/mitigate the failure consequences. This approach presupposes that there is some kind of deterioration in either asset condition or performance occurs and that this can be detected in some way. For asset components whose failure modes are essentially random or cannot be detected, then other risk management approaches must be used. Many failure modes will however give some sort of warning that they are about to occur. Inspection tasks designed to detect potential failure are often referred to as condition-monitoring tasks. Figure 5-2 illustrates the stages of asset failure in a plot called a P-F curve. The conceptual basis behind these curves is that asset condition of many assets deteriorates over time and the level of deterioration eventually progress to the point where it is significant and can be detected (Point P). At this point, it is possible to intervene in the deterioration process and correct the defects or replace failing components (or at the very least, take action to minimize the consequences of failure). If the 5-4

deterioration is not detected and corrected, the asset continues to deteriorate until it reaches the point of functional failure (Point F). In practice, there are many ways of determining the onset of the failure process, for example, hot spots showing deterioration of electrical insulation, vibrations indicating imminent bearing failure or increasing level of contaminants in lubricating oil. The succession of techniques that can be used is discussed in Chapter 6.0. Summaries of the available inspection tools and techniques are detailed in Chapter 7.0. Figure 5-2. The Failure Process as Described by the P-F Curve (adapted from ABS, 2004). The time interval between point P and point F is called the P-F interval. This is the time between the point at which the onset of the failure process becomes detectable and the point at which a functional failure occurs. Condition-monitoring maintenance task intervals must be determined based on the expected P-F interval. If a condition-monitoring task is performed on intervals longer than the P-F interval, the potential failure may not be detected. On the other hand, if the condition-monitoring task is performed too frequently compared to the P-F interval, resources are wasted. The following sources may be referred to as an aid to determine the P-F interval (ABS, 2004): Manufacturer s recommendations. Expert opinion and judgment. Published information about condition-monitoring tasks. Historical practices (e.g., current condition-monitoring task intervals). The P-F interval can vary in practice and in some cases can be very inconsistent. For such cases, a condition monitoring task interval should be selected that is substantially less than the shortest of the likely P-F intervals. 5.3.2 The Role of Performance Assessment The International Infrastructure Management Manual (IPWEA, 2006) notes that asset condition and performance failure can be considered as a cause and effect respectively, in that deterioration of condition is a cause of failure, and the effect of failure is poor asset performance. In conjunction with an appropriate inspection regime, performance assessments therefore represent another key component to management of asset capabilities. Performance assessments can be undertaken at three levels of detail: Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 5-5

Strategic assessments Tactical assessments Asset level At a strategic level, a well-implemented performance management system provides information that can be used for optimizing maintenance strategies and identifying issues related to capacity. For example, through collection and analysis of asset-related KPIs, utilities can evaluate the effectiveness of their maintenance programs and modify policies and procedures appropriately. This type of strategic performance assessment is considered in more detail in Chapter 2.0. At a tactical level, maintenance planning can be facilitated through prediction and trend analysis based on reliable performance information, especially in the form of reactive maintenance tasks (tasks undertaken in response to failure events). This functionality is often provided by a computerized maintenance management system (CMMS). A CMMS facilitates utilities in creating and tracking work orders and transferring data to and from other modules in corporate databases. This allows the maintenance data within a CMMS to be mapped, analyzed and combined with other condition assessment information to yield maintenance solutions (ASCE, 2004). At the asset level, on-going assessment of asset performance against current and future performance requirements helps to determine the assets current capability (considering issues such as obsolescence and capacity requirements) and the need for preventive maintenance. In this later context, monitoring asset performance is also a condition-monitoring technique. As such, the process of identifying the onset of failure through monitoring of performance can also be described using the P-F curve given in Figure 5-2. In condition monitoring of this type, however, the approach is to anticipate the onset of a functional failure through the early identification of changes in operational variables such as pressure, temperature, flow rate, electrical power consumption and/or asset capacity. 5.4 Risk-based Assessment Procedures As described previously, proactive maintenance can, in practice, only be applied to a limited number of assets. As a sub-set of proactive maintenance tasks, condition monitoring is similarly applicable only when the benefits of undertaking the monitoring outweigh the costs. A number of approaches are available to help utilities develop an effective maintenance strategy and to determine the assets that should be reactively managed and the assets for which proactive maintenance is required. These methods are based on the generation and comparison of relative risk for different maintenance strategies. Case Study Inset 5-1 encapsulates the key components of the analysis at the asset level. 5-6

Case Study Inset 5-1: Classification of Asset Risk A common practice for classifying asset risk is to allocate a grade according to the frequency and severity of failure. This can be extended to consider the detectability of the failure. Such an approach can be used in failure modes, effect and criticality analysis (FMECA) and is applied by Sydney Water. Assets are allocated a risk category using the formula below. Risk category = Occurrence X Severity X Detectability Occurrence (or frequency) is an estimation of how frequently a specific failure may occur. Rankings range from: 1 - unlikely, defined as unreasonable to expect failure to a rank of 5 - high, defined as recurrent or certainty of failure. Severity (or consequence) is an assessment of the seriousness of the effect of the potential failure mode with respect to equipment, process or consumer. Sydney Water uses the severity rankings given in BS 5760-0:1986: Reliability of Systems, Equipment and Components. Detectability gives an indication of how easy or difficult it is to detect the symptom of failure, preferably before it occurs or before the process is adversely impacted. Sydney Water uses predetermined rules to determine what detectability scores are assigned to an asset to ensure consistency across similar assets. A rank of 1 corresponds to a very high detection probability; failure always preceded by a warning while a rank of 5 corresponds to a remote (detection) probability; failure always without a warning. The output of the analysis is a risk rating for each piece of equipment, known as the risk priority number (RPN). The RPN represents the degree of risk associated with equipment or a particular process. Through experience, Sydney Water has determined that a RPN equal to or greater than 33 warrants an immediate detailed inspection of the asset. A decision is then made as whether the asset should be repaired or renewed. See Case Study 9 in Chapter 8.0. When applied across a system of assets, the characterization of asset risk in conjunction with assessments of cost allows the utility s maintenance regime to be optimized in terms of the total cost of proactive and reactive maintenance, including the impact of asset failures. Examples of riskbased assessment methods include risk based inspection (RBI) and reliability centered maintenance (RCM). RCM involves consideration of all proactive maintenance tasks and is applied across a range of asset types, generally above ground assets, whereas RBI focuses more narrowly on the optimization of inspection programs for static assets, especially pressure equipment and structures. These techniques are considered in more detail below. 5.4.1 Reliability Centered Maintenance Nowlan and Heap (1978) coined the term reliability centered maintenance as a process to be used to draw up maintenance programs for aircraft before they entered service (Moubray, 1997). In this original context, RCM was developed specifically for use in the design phase of an asset s life cycle. However, Moubray (1997) subsequently defined RCM as a process used to determine maintenance requirements of any physical asset in a given operating context. As such, RCM is now applied retrospectively to systems of assets well into their life cycle. According to Moubray (1997) and SAE JA1011 (1999), the RCM process involves asking seven questions about the assets/components within a system under review. The questions are asked and answered in a structured manner by a facilitated RCM team. A process analogous to failure modes and effects analysis (FMEA) is used to analyze the asset failures. Software tools can be used Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 5-7

to facilitate the process. It should be noted that RCM by design is intended to preserve system function (Nowlan and Heap, 1978), rather than preserve the asset/equipment condition. The seven RCM questions are shown in Case Study Inset 5-2 with additional comments included in the discussion that follows. Case Study Inset 5-2: The Seven RCM Questions Q1. Functions: what are the functions and associated desired standards of performance of the asset in its present operating context? Q2. Functional failures: in what ways can the asset fail to fulfill its functions? Q3. Failure modes: what can cause each functional failure? Q4. Failure effects: what happens when each failure occurs? Q5. Failure consequences: in what way does each failure matter? Q6. Pro-active tasks: what can be done to predict or prevent each failure (proactive tasks and task intervals)? Q7. Default actions: what should be done if a suitable proactive maintenance task cannot be found? The start of the RCM process requires that each asset function be determined and a performance standard assigned (Q1). The functions of an asset must be specified in sufficient detail to allow the analyst to define functional failures. All failed states associated with each asset function must then be identified (Q2). If functions are well defined, listing functional failures is a relatively straightforward task. For example, if the defined function is to keep system pressure between 4 and 7 bar, then functional failures will include unable to raise pressure, unable to keep system pressure above 4 bar or unable to keep system pressure below 7 bar. All failure modes that are reasonably likely to cause each functional failure must be identified (Q3). The list of failure modes should include 1) failure modes that have happened before, 2) failure modes that are currently being prevented by existing maintenance programs and 3) failure modes that have not yet happened but are thought to be reasonably likely given the operating context. Failure modes are identified to allow the physical effects of a failure to be evaluated (Q4), including what would happen if no action were taken to anticipate or prevent it. The consequences of each failure mode must then be specified (Q5) as if nothing were being done to prevent it. RCM assigns consequences to one of four categories: hidden, evident safety/environmental, evident operational and evident non-operational. The question is then asked, what can be done to prevent the failure? to determine what maintenance tasks should be carried out to predict or prevent failures (Q6). As discussed previously, only those tasks that are worth doing (to prevent consequences) should be undertaken. An important corollary of this is that when considering existing maintenance schedules, tasks that have little effect on failure rates or consequences should be eliminated. This elimination of redundant tasks is an important part of the RCM optimization process. The final task in the RCM analysis is to consider what should be done in the event that the failure cannot be either predicted or prevented (Q7). Approaches that may be considered include 5-8

unscheduled failure management policies and changing the asset s operating context (such as its design or the way it is operated). It can be seen that condition monitoring will form part of the actions undertaken to address Q6, that is: Pro-active tasks: what can be done to predict or prevent each failure (proactive tasks and task intervals)? The task interval would be set in proportion to the risk and the P-F interval described earlier. Case Study Inset 5-3 shows how one utility s approach to RCM contributes to the management of its pumping station assets. Case Study Inset 5-4 shows the scale of benefits that can be accrued through the adoption of this approach. Case Study Inset 5-3: Water Care s Management of its Pumping Station Water Care (New Zealand) has 51 pumping stations in its network (ranging from 10 liters/second to 4,000 liters/second). SCADA monitoring all stations includes alarms, hours run and pump stop/start data. The overall maintenance strategy is set using an RCM approach. Maintenance tasks and frequency are set on the basis of past experience, review of manufacturer s manuals and feedback from maintenance teams. FMECA analysis is used to understand implications of system, sub-system and component reliability. Planned preventive maintenance program includes monthly inspections, scheduled wet well cleaning, general civil and site maintenance and standard mechanical and electrical maintenance tasks. Inspections include scheduled pump vibration analysis, thermography and electrical mega testing. Case Study Inset 5-4: Massachusetts Water Resources Authority (MWRA) RCM Program Implementation of a formal RCM program has been a very effective way for MWRA to enhance asset reliability and performance and to reduce life cycle costs of its large facility equipment. Benefits accrued have been primarily from the Deer Island Treatment Plant RCM program and associated condition monitoring on major equipment. MWRA has recognized the following benefits: Demonstrated reduction in over 20,000 maintenance work hours per year as a result of all reliability programs including RCM, condition monitoring, preventive maintenance optimization and productivity improvements, resulting in labor savings of over US$700,000 annually. Proactive oil sampling program resulted in avoided (scheduled) oil changes valued at roughly US$50,000 per year. Substantial (non-quantifiable) avoided and deferred costs due to enhanced equipment reliability and performance, extended equipment life, avoided permit violations, etc. Qualitative staff improvements in terms of teamwork, communications and commitment to success. Investments in staff training, sophisticated mechanical alignment equipment and permanent monitors on certain major equipment have also yielded savings in asset life cycle costs and performance reliability. See Case Study 11 in Chapter 8.0. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 5-9

5.4.1.1. Reducing the Cost of RCM Analysis By design, RCM is a comprehensive, detailed, and therefore time consuming and expensive process to apply. As such, large companies require a screening approach to prioritize studies or determine to which assets (treatment works, pumping stations, etc.) this (or a similar) procedure will be applied. Such an approach is summarized in Case Study Inset 5-5, though as noted, it is understood that a formal RCM procedure was not adopted in the analysis. The process presented is, however, equally applicable to RCM and other approaches to maintenance optimization. Case Study Inset 5-5: Scottish Water s Screening of Treatment Works When Scottish Water was designing the implementation of a risk based maintenance strategy, it was determined that not every site (treatment works, pumping station, etc.) could be analyzed in detail. As such, they ranked sites in terms of importance considering a range of factors, including: Size (population served) Available standby capacity Storage Plant complexity (number of assets, SCADA, etc) Stringency of consents (for wastewater) From this ranking, the maintenance strategy to be adopted was specified such that: 1) the top 10% of assets were subject to full risk based maintenance planning procedure, 2) the next 20% were treated with a generic approach using task lists and 3) the final 70% were allocated standard tasks and frequencies (e.g., an annual visit) associated with basic care. For the full risk based maintenance planning procedure, a full failure mode analysis was undertaken (using FMECA) at the unit level. The analysis was undertaken by a specialized team in conjunction with operational and maintenance staff. Three fundamental questions were asked of each asset to focus the analysis: Is the asset operating? Is the asset performing satisfactorily in terms of failures? Is the asset fit for purpose? As well as undertaking screening analysis to determine which assets the RCM process should be applied to, the cost of undertaking RCM analysis can be reduced by adopting a streamlined RCM approach. According to Moubray (2002), the different streamlined approaches are characterized by a retroactive focus. The RCM starts not by defining the functions of the asset, but with existing maintenance tasks. Furthermore, generic lists of failure modes are used and the analysis performed on one system is applied to other similar systems (Backlund, 2003). Proponents of streamlined RCM claim they achieve similar results to the full RCM process, but with much less time and thus lower costs (Backland, 2003). In contrast, Moubray (2002) considers that the use of such streamlined approaches do not achieve the same results as full RCM studies. However, as noted by Turner (undated), few organizations have applied RCM to anything other than their most critical assets, suggesting that there is a real need for an alternative. As such, streamlined RCM approaches such as preventative maintenance optimization (PMO) offer a pragmatic approach to the process of review for assets that have an established maintenance program (formal or informal) but where that maintenance program was inefficient or misaligned with business needs (Turner, undated). 5-10

5.4.2 Risk Based Inspection In the past, inspection techniques and frequencies were typically based on manufacturer s recommendations, industry standards or regulatory requirements. Inspection frequencies were set in terms of time-based or calendar-based intervals. Since knowledge of asset operation and deterioration evolves over time through user experience, such practices do provide an adequate level of maintenance and asset protection. These traditional approaches do not, however, explicitly consider risk, the asset s operating context, or the impact of the assessed condition on the required inspection interval. As a result, the inspection programs generated do not necessarily provide an optimal balance between cost of inspection and asset-related risk throughout the asset lifecycle. In contrast, by considering current condition, risk and operating context, an acceptable level of reliability and risk could be achieved at lower cost. Various sectors have recognized that significant benefits may be gained from adopting more informed inspection scheduling techniques (ABS, 2003). Factors such as operating experience, deterioration rates and consequences of failure are considered along with the asset condition to give an inspection interval that seeks to achieve a balance between risk and the level of inspection effort. A technique that applies this philosophy is RBI. RBI focuses on the optimization of inspection programs for static assets; especially pressure equipment and structures. RBI begins with the recognition that the essential goal of inspection is to prevent failures. By explicitly considering risk, RBI assures inspection resources are focused on the areas of greater concern and provides a methodology for determining the optimum combination of inspection methods and frequencies (ABS, 2003). Case Study Inset 5-6 shows the basic elements of the RBI approach. Case Study Inset 5-6: Risk Based Inspection According to the American Bureau of Shipping (ABS, 2003), the basic elements in the development of an RBI program are summarized in the following steps: 1. The determination of the risk introduced by the potential failures of each asset component. 2. The identification of the degradation mechanisms that can lead to component failures. 3. The selection of effective inspection techniques that can detect the progression of degradation mechanisms. 4. The development of an optimized inspection plan using the knowledge gained in the three previous items. 5. The analysis of the data obtained from the inspections and any changes to the installation in order to feed back into the RBI plan. The setting of inspection frequency within RBI is not a rigid process with fixed, predetermined inspection intervals. Inspection intervals may change throughout the life of the asset as risk increases or decreases. There is, however, a general logic to the inspections and frequency of the inspections, as highlighted in Case Study Inset 5-7, which can be summarized thus: Higher risk systems/components generally have the shorter frequencies of inspection and have potentially larger inspection population requirements. Lower risk systems/components often have extended inspection frequency (or even no inspection) and have reduced inspection population requirements. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 5-11

Case Study Inset 5-7: Risk Based Inspection of Melbourne Water s Tanks In 2005, Melbourne Water operated thirty-eight steel service reservoirs (40 were being operated at the time of writing), with an estimated replacement value of AU$190 million. Due to a design issue inherited by Melbourne Water (see Case Study 8 for details), a number of these tanks are prone to under floor corrosion. The failure mode associated with this under floor corrosion is not catastrophic. However, significant leaks can occur. Given the high visibility of water conservation issues in Australia, coupled with the proximity of the tanks to residential areas, such leaks can result in significant adverse publicity as well as having the potential for causing property damage and associated community distress. Given the perceived level of risk, Melbourne Water s steel service reservoirs are now regularly inspected to ensure that the potential for asset failure is appropriately managed. Inspection strategies have been developed in consultation with external consultants and are considered by Melbourne Water to be industry best practice. Comprehensive corrosion assessments are undertaken on a periodic basis ranging from one to five years. Generally speaking, assets that are deemed to pose a significant risk are inspected on a one to two year basis, whereas those that pose a smaller risk are inspected on a three to five year basis. Outage strategies are implemented based on business risk and operational needs with due consideration given to both water quality standards and structural integrity requirements. The inspection can be timed in accordance with cleaning requirements; tanks have to be cleaned every three to eight years, depending on the level of silt build up. See Case Study 8 in Chapter 8.0. 5.5 A Generic Approach to Specifying Condition Monitoring Tasks It is interesting to note that all risk-based assessment methods, including RCM, RBI and FMECA, share a basic structure in that the methods all consists of an exploration of the system under study to address issues that are, in essence, captured by the first five questions of the RCM approach: 5-12 1. What are the functions and associated desired standards of performance of the asset in its present operating context? 2. In what ways can the asset fail to fulfill its functions? 3. What causes each functional failure? 4. What happens when each failure occurs? 5. In what way does each failure matter? The difference between the various approaches is the optimization process that is used, whereby inputs (e.g., inspection/maintenance regimes) are compared against outputs (e.g., cost and associated risk) to provide a desired outcome (e.g., an optimal inspection/maintenance regime). Given the commonality between the approaches, it is a relatively straightforward task to specify a generic approach to identification of condition monitoring tasks. This is illustrated in the flow diagram shown in Figure 5-3. The selection process in the last box of Figure 5-3 is essentially a cost benefit analysis taking into account the level of risk exposure. It is again important to note that the selection process embedded in Figure 5-3 presupposes that there is some kind of detectable deterioration in either asset condition or performance. For

assets or components whose failure modes are essentially random or cannot be detected, then condition monitoring is not an appropriate strategy and other risk management approaches must be used. Figure 5-3. A Generic Approach to Specifying Condition Monitoring Techniques. Optimization of condition monitoring should ideally be done across the asset stock, although this optimization does not necessarily have to be undertaken formally; the process of analyzing risk and assessing cost of condition monitoring relative to potential consequences will provide optimization to a degree. 5.5.1 Critical Defects and Performance Thresholds The performance thresholds and critical defects indicated in Figure 5-3 should be taken as being equivalent to point P in the P-F curve shown in Figure 5-2, that is, they are thresholds that indicate that the failure process has progressed to the point where action is required. As noted previously, there is a tendency for engineers to manage the condition of assets, not least because early intervention in the deterioration process can significantly prolong the life of an Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 5-13

asset. However, there are in general more tasks to do than there are resources with which to do them. Therefore, it is important to prioritize activities in some way. A key task in the development of any effective condition monitoring process is the need to determine what critical defects and performance thresholds are, and what these mean in relation to the asset s remaining service life and need for action. For example, given that a defect is observed, the interventions available range from doing nothing through repair or replace. In the later case, the observed defect would indicate the asset was at the end of its useful life. When determining what intervention to adopt for a particular asset, there is a great reliance on expert opinion drawing on previous actions to address defects and taking into consideration a range of data, including: 5-14 The type and severity of the defect. The context of operation. Consequential impacts should the asset fail. In essence, the engineer assessing the defect needs to decide if maintenance is needed, and if so, what scale (repair, replacement) and if not, what action should be taken instead. This could range from doing nothing through implementing condition monitoring or specify a re-inspection within a time interval deemed appropriate to the risk. In interpreting defects, there is a tendency for individuals to be risk averse in their interpretations and recommendations. There is thus a need for standard guidance on what constitutes a significant defect for a range of asset types in a range of operational contexts. Such guidance is, however, beyond the scope of this report. 5.1 Development of a Condition Monitoring Program When considering a change to any maintenance activity, the key challenge faced by a maintenance manager is to consider what level of activity is appropriate. In practice, this often reduces to the need to determine what percentage of the maintenance budget and resources can or should be dedicated to a given activity. The remainder of this chapter considers this challenge from the perspective of developing a condition monitoring program, including how such a program is justified. For the purposes of this discussion, it is assumed that condition monitoring is already undertaken in one form or another, so any program will involve a change to the current practices. A case study is provided below to illustrate how a water utility went about changing its condition monitoring practices to increase the amount of condition-based maintenance being undertaken. While the case study shows some of the logic behind the development of a predictive maintenance program, no attempt is made to give an exhaustive treatment of this subject; the interested reader is referred to the literature on maintenance program development (e.g., the work of R. Keith Mobley, The Plant Performance Group). The case study presented relates to a project undertaken in 2002/2003 by MWRA. The project sought to determine how MWRA should build upon its existing condition monitoring capacity at the Deer Island Treatment Plant (DITP). At the time the case study project was conceived, various condition-monitoring technologies were already in use at the DITP; including vibration monitoring, oil analysis, infrared thermography and ultrasonic detection. Data collection and analysis had, however, not been fully implemented, and management of the technologies was being undertaken by different groups, for example: The Electrical Engineering group managed the use of thermography. The Maintenance Work Coordinatio group managed the use of oil sampling.

Since a major strength of a predictive maintenance program is achieved when two or more complimentary technologies are used together (an example of this would be when a gearbox exhibits high levels of wear particles in an oil sample; vibration analysis could then be used to determine how extensive the wear is), the MWRA management team at DITP recognized that this separation of responsibilities and, more importantly, the inevitable separation of findings/data did not allow the full benefit of the condition monitoring techniques to be realized. The case study project was initiated to develop a program under which condition-monitoring responsibilities could be brought together within a single group. In addition, a key objective was to increase the predictive monitoring capacity at the DITP to create a more effective maintenance regime and move away from interval based maintenance where possible. 5.1.1 Program Development An important first step in any program development is to understand and document what is to be achieved. In the case of a change to a condition-monitoring program, the main driver will often be a reduction in overall cost through a combination of: Improvements to maintenance regimes, to increase asset reliability/availability and thereby reduce the cost of asset failures and equipment downtime; and Justifiable reduction in overall maintenance effort; for example, converting a non-condition based (interval based) preventive maintenance program to a condition based program, which can realize significant savings in maintenance hours, parts, and so forth. Once drivers are clarified, some technique must then be used to determine what condition monitoring activities are required to achieve the program s objectives. The necessary resources and equipment must be identified. When undertaking these tasks, two approaches can be adopted. The ideal approach is to assess the maintenance tasks required through a systematic technique such as RCM, and then assess the budgets and resources necessary to allow these tasks to be undertaken. The more pragmatic approach is to assess what can be done given available resources and level of management commitment, and tailor the plan to these constraints. Whichever approach is taken, the implementation of a program to modify any maintenance practice requires a well-structured plan for staffing and work management to be developed. In general, staff will be required to fulfill the following functions: Management of the maintenance activities and team members. Collation and analysis of data. Undertake the condition monitoring tasks themselves. 5.1.2 Planning for Program Success Justification of a condition-monitoring program should ideally be based on economic analysis in which the relative cost-benefits of the program are assessed. The data for costs can generally be obtained from a utility s records or by contacting practitioners who either offer the required services or have experience using the condition monitoring techniques of interest. Accurate information on benefits is, however, difficult to obtain because it requires that the benefits of avoiding future failures are estimated in some way. Unfortunately, the variables that influence the cost of failure are often unique (due to variations in conditions, events, equipment types, operational situations, etc.), and various assumptions must be made when undertaking analysis of a proposed program. The analysis can incorporate a high degree of subjectivity and associated uncertainty. As well as issues relating to uncertainty of benefits, any change to a maintenance regime can be expected to cause some disruption to the activities of maintenance staff. For example, converting Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 5-15

a non-condition based (interval based) preventive maintenance program to a condition based program requires the reassigning of resources from the existing maintenance program to the new program. However, there is often a lag between the introduction of the new maintenance regime and the benefits of the program (e.g., reduction in failures). A period of disruption and additional workload can be anticipated for the maintenance department until the results of the program start to be seen. While additional resources and funding can be made available to help overcome this initial period of net-disruption, it makes sense to start the predictive maintenance program with the least amount of impact on the existing maintenance program, while supporting the effort well enough to ensure a successful transition. In recognition of these issues, a phased implementation plan can be developed in an attempt to minimize the impact of uncertainties and any disruption. For example, in the case of the DITP program, it was determined that the most logical approach for planning the implementation of a predictive maintenance program was to: Start out slowly, beginning with the implementation of the most versatile predictive maintenance tools as they apply to a given facility. Establish and ensure that the minimum amount of savings required to break even on the investment of capital and resources was achievable. Expand the program as real savings were realized and when the most beneficial applications of the technology at the plant were identified. In DITP s case, significant capacity existed in vibration monitoring, oil analysis, and thermography. Since all three of these technologies were being used, it was anticipated that each would require little initial investment and minimal additional training to progress the programs. Initial focus was given to the increased use of these technologies. It was also considered likely that ultrasonic detection could be implemented due to the low cost of equipment and the simplicity of the technology. 5.1.3 Resource Issues Mobilizing sufficient resources to ensure a new program s success can often be an issue, given the demands of existing tasks. Again, a pragmatic approach may be needed in light of resource constraints. For example, in the case study it was recognized that the most effective course for guaranteeing the success of the overall program would be to devote selected maintenance personnel to a new condition-monitoring group on a full time basis. The group consisted of a condition-monitoring manager and two condition-monitoring engineers, with responsibilities for analyzing all condition monitoring data, providing recommended corrective actions, and to organize and implement condition-monitoring technologies. To supplement this group and to support the condition-monitoring effort, technicians throughout the facility were trained on basic condition monitoring techniques and to take all vibration readings and oil samples. These technicians work part time each month on these activities. As the program evolved and demonstrated its cost effectiveness, the commitment of technicians to supplement the group s activities increased significantly. 5.1.4 Cost Benefit Analysis As noted above, justification of a condition-monitoring program is ideally based on economic analysis in which the relative cost-benefits of the program are assessed. The development of a cost-benefit analysis requires that the following tasks be undertaken: An evaluation of the condition monitoring tasks to be undertaken (in terms of the technologies and approaches to be used, and frequency/asset coverage). 5-16

An evaluation of equipment. An estimation of resources. An estimate of associated costs, including: o Training. o Software and equipment. o Labor. o Contracted support services (e.g., lab testing and specialized data). o Program management/administration. An estimate of benefits (in essence, an evaluation of failure avoidance and other benefits such as improvements in asset reliability/availability and reduction in maintenance spend). 5.1.4.1 Case Study Example In the case of the DITP, prior to providing a full commitment of resources to the program, a cost benefit analysis was conducted for five condition-monitoring technologies: vibration monitoring; oil analysis; thermography; ultrasonic detection, and motor current signature analysis. However, rather than attempt to predict all potential savings that could be achieved at DITP, a cost benefit analysis was undertaken to: Establish the costs associated with instituting a basic condition monitoring group, and then, Identify if there was the potential to recoup the investment based on the type of equipment, the expected failures, and the estimated average savings that could safely be attributed to predicting a percentage of those failures. Resourcing of the Group Given a pragmatic review of the available resources, and the level of condition monitoring to meet the aims of the initial program, it was recommended the Condition Monitoring Group structure as originally constructed included the following positions and associated labor dedication: Group Manager 30% of full time for managing the group. Data Coordinator / Planner 100% of full time. Vibration Technician 20% of full time to begin evolving to a minimum of 50%. Oil Sampling Technician 20% of full time to begin evolving to a minimum of 50%. Thermography Technician 20% of full time to begin evolving to a minimum of 50% Ultrasonic Technician 10% of full time to begin evolving to a minimum of 20%. Specialized training in each of the specific technologies was recommended for each of the positions, including training for the data coordinator and group manager in all of the technologies. It was further recommended that the number of technicians to be trained should be based on the level of back-up personnel required to cover for vacations, sickness and so forth. After further development of the condition monitoring program additional resources were allocated, which included a group manager and two data coordinators/planners. In addition, as noted above, technician support throughout the facility is provided. Program Costs Based on the recommended group structure and estimated percentages of full time effort for each position, MWRA was able to estimate the cost of operation for the Condition Monitoring Group over a 10 year period, as summarized in Table 5-2. Much of the capital expenditure (equipment costs) had already been made, so this cost element could be excluded from the analysis. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 5-17

Vibration Monitoring Benefits To quantify the benefits of the vibration-monitoring program over the course of 10 years it was necessary to make the following assumptions: The program would be expanded from the initial population of 98 pieces of equipment to a population of 318 pieces of equipment. The incidence of failure avoidance will increase at a rate of 3% per year as the plant equipment began to experience more age related failures. The incidence of failure avoidance will increase at a rate of 2% per year as the vibration monitoring personnel become more experienced. The documented cost avoidance (the estimated cost of avoided damage directly attributable to the condition monitoring) for the vibration-monitoring program over the previous two and a half years was a total of US$57,700 for an average of US$23,080 per year. Based on the above assumptions and documented cost avoidance, Table 5-1 shows the estimated projection of the vibration monitoring cost avoidance benefits over a 10-year period. Table 5.1. Estimated Projection of the Vibration Monitoring Cost Avoidance Benefits (US$). FY1 FY2 FY3 FY4 FY5 FY6 FY7 FY8 FY9 FY10 10-Year Total Failure Cost Avoidance FY0 = 23k 51.3k 82.4k 86.6k 91.0k 95.6k 100k 105k 110k 116k 122k 960k A simple return on investment (ROI) calculation for the vibration-monitoring program over a 10-year period was undertaken, as represented by the following: ROI = [(US$960k (10 Yr Benefit) US$483.1k (10 Yr Cost)) / US$483.1k (10 Yr Cost)] x 100 ROI = 98.7% 5-18

First Year Costs Table 5-2. Ten-Year Projected Condition Monitoring Costs (US$). Vibration monitoring Oil sampling Thermography Ultrasonic detection Initial training $16,000 (8 Persons) $8,000 (4 persons) $9,000 (4 persons) $4,800 (4 persons) Software purchase Included with equipment Not required Included with equipment Not required Equipment purchase $40,000 (2 port. Units) $1,000 (sample equip) $40,000 $3,000 Miscellaneous group management Manager labor $4,600 $4,600 $4,600 $2,280 $6,920 Data coordinator labor $16,800 $16,800 $10,080 $6,720 $16,800 Technician labor $9,600 $9,600 $9,600 $4,800 Contracted support services $5,000 (analysis of data) $9,000 (lab costs) $0 $0 Total expenditure $52,000 $48,000 $33,280 $18,600 $23,720 Note: Total expenditure excluded Equipment Purchase as investment had already been made in the necessary equipment. Subsequent Years Costs (average): all future costs are listed at present day values without consideration of discount rate (NOT net present value). Training $1,500 $1,500 $1,500 $500 Calibration and upgrades $5,000 $0 $2,000 $0 Manager labor $4,600 $4,600 $4,600 $2,280 $6,920 Data coordinator labor $16,800 $16,800 $10,080 $6,720 $16,800 Technician labor $24,000 $24,000 $24,000 $9,600 Contracted support services $1,000 $18,000 (lab costs) $0 $0 Annual costs $47,900 $64,900 $42,180 $19,100 $23,720 Subsequent 9-year cost $431,100 $584,100 $379,620 $171,900 $213,480 Estimated 10-year cost $483,100 $632,100 $412,900 $190,500 $237,200 Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 5-19

Oil Analysis Benefits To quantify the benefits of the oil analysis program over the course of 10 years it was necessary to make the following assumptions: The program would expand from the initial population of 106 pieces to approximately 300 pieces of equipment. The incidence of failure avoidance will increase at a rate of 3% per year as the plant equipment begins to experience more age related failures. The incidence of failure avoidance will increase at a rate of 2% per year as the oil analysis personnel become more experienced. The incidence of oil usage cost avoidance will increase at the rate of US$10,000/year as equipment is added to the program over the next three years. The documented failure avoidance cost (the estimated cost of avoided damage directly attributable to the condition monitoring) for the oil analysis program over the previous eight months was a total of US$56,970 for an average of US$85,455 per year. The documented annual oil usage avoidance cost for the oil analysis program over the previous eight months was a total of US$30,000. Based on the above assumptions and documented cost avoidance, Table 5-3 shows the estimated projection of the oil analysis cost avoidance benefits over a 10-year period. Table 5-3. Estimated Projection of the Oil Analysis Cost Avoidance Benefits (US$). FY1 FY2 FY3 FY4 FY5 FY6 FY7 FY8 FY9 FY10 10-year total Failure cost avoidance FY0 = 85k Usage cost avoidance FY0 = 30k 144k 208k 279k 293k 307k 323k 339k 356k 375k 394k 2.8M 40k 50k 60k 60k 60k 60k 60k 60k 60k 60k 570k A simple ROI calculation for oil analysis program over a 10-year period was undertaken, as represented by the following: ROI = [(US$3.37M (10 Yr Benefit) US$.632M (10 Yr Cost)) / US$.632M (10 Yr Cost)] x 100 ROI = 433% Thermography Benefits Because DITP did not have documented data on cost avoidance for the thermography program, a predictive maintenance consulting company was contacted for assistance in developing cost benefit values. The consulting company provided figures that represented typical costs and savings for a large facility; the annual gross benefits provided by the consulting company were estimated at US$300k. A simple ROI calculation for the thermography program over a 10-year period was undertaken using a more conservative annual gross benefits figure of $100k, as represented by the following: Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 5-21

ROI = [($1.0M (10 Yr Benefit) $.413M (10 Yr Cost)) / $.413M (10 Yr Cost)] x 100 ROI = 142% Ultrasonic Detection Benefits Because ultrasonic detection had not been used at DITP for any extended period of time and data associated with failure avoidance was not available, anticipated benefits could not be calculated. The anticipated use of the ultrasonic unit was to include evaluation of rotating element bearings on equipment where the criticality of the equipment did not warrant the time and effort associated with vibration analysis. For the purposes of the analysis it was assumed that if it could be determined that the program would detect a sufficient number of bearing problems to avoid maintenance costs exceeding the cost of the program, the ultrasonic program would be considered be viable. Actions that would avoid maintenance costs include alignment, lubrication and bearing replacement prior to damaging pump/shaft. A value of US$1,000 per avoided cost of bearing failure was used in the following calculation. No. of Bearing Failures/yr = Avg. Annual Program Cost/Avoided Cost of Bearing Failure No. of Bearing Failures/yr = US$19,050 / US$1,000 No. of Bearing Failures/yr = 19 Since the ultrasonic program would be surveying hundreds of bearings per year, it was concluded that 19 bearing problems detected per year was almost certain. Results of the Analysis From the above analysis it was determined that continued implementation of vibration monitoring, oil analysis, thermography and ultrasonic detection would produce a return on investment. Although justifiable from a cost benefit viewpoint, it was recommended that the implementation of motor current signature analysis should be delayed in an effort to minimize the commitment of labor resources and training for the condition-monitoring program. 5-22

CHAPTER 6.0 SELECTING TOOLS AND TECHNIQUES Chapter Highlights A significant number of assessment techniques and inspection tools have been identified in this project. Research has shown that the selection of an appropriate tool or technique is highly context specific. A generic approach to tool selection is outlined, which uses an exclusion process to identify options that can be considered. Tools are excluded on the basis of technical feasibility, suitability and capacity. Useable options are then evaluated through economic or financial analysis. A number of important selection criteria have been identified to guide the selection process. Where possible, the attributes relating to the criteria have been evaluated for each of the tools and techniques identified and reviewed in this research. These attributes summarize the application and use of the tools and provide the information necessary to undertake the selection process. A key goal of the research was to provide a framework that would assist organizations in the selection of condition assessment tools. A paper-based solution is presented to facilitate this process. Initial work has also been undertaken into the development of a prototype expert system for this application. A direct extension of risk-based arguments used herein is that the more important the asset is, the more expense can be justified in assessments undertaken to ensure the asset does not fail. However, to minimize costs, inexpensive tools should still be used where possible. As such: Inexpensive screening tools and approaches should be used routinely. The results of the screening approach may dictate that there is a need for additional information and/or accuracy. This may require the use of more sophisticated assessment or inspection tools. Additional expense should be considered only when justified in terms of risk costs avoided or benefits accrued. This logic is used to present an iterative approach to the use of tools, where more sophistication and accuracy is used to fill information gaps left by screening tools. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 6-1

6.1 Introduction A significant number of assessment techniques and inspection tools were identified in this project. Furthermore, the research showed that the selection of an appropriate inspection tool or condition assessment approach is highly dependent upon what outcomes are required from the assessment, the capacity of the tool/technique to provide the necessary information, the availability of appropriate data to interpret the results, the capacity of the utility to utilize the selected tool/technique and economic factors. The issues involved in tool selection are thus complex, and can be summarized by considering condition assessment from three overlapping viewpoints, namely: Asset Focused View: how critical is the asset in question and what is justified to manage the risk; this is the RCM type approach discussed in Chapter 5.0. Situation Focused View: what are the drivers and what is justified to address them; for example, the need to understand risk and impact of capital deferral; need to address litigation. Tool Focused View: when would a specific tool normally be used; for example, opportunistically, as a screening tool, for the regular inspection of important assets, monitoring of critical assets, etc. This chapter presents an approach to aid utilities in selecting appropriate condition assessment tools and techniques, which takes into account each of these views. A generic approach to tool selection is first outlined, which uses an exclusion process to identify options that can be considered. The role of risk and cost in determining what tool to use for a particular set of circumstances is then considered, and a sliding scale of assessment standards suggested. 6.2 A Protocol for Selecting Condition Assessment Tools As noted above, a significant number of assessment techniques and inspection tools were identified during this research. Listing all these tools and mapping them onto the asset stock is a useful task, but it is more desirable to help utilities to undertake their own selection of suitable tools and techniques given their unique knowledge of the assets that need assessing, the drivers behind the assessment, and the likely end uses of the information. The International Infrastructure Management Manual (IPWEA, 2006) presents an approach to the selection of condition monitoring techniques that involves a process where the utility 1) assesses the condition and performance assessment techniques being used already, and 2) develops an understanding of any shortfalls. This gap analysis then drives the selection of new approaches and/or tools. This process is shown in Figure 6-1 (this is a simplified version of the flow chart given in the International Infrastructure Management Manual (IPWEA, 2006). An example of a utility using this type of approach is summarized in Case Study Inset 6-1. While this approach is perfectly valid, it assumes that condition monitoring already plays a central role in the utility s asset management approach, and that the utility simply wants to assess whether better approaches are available to those already in use. This logic is generally applicable to the use of condition assessment/monitoring within day-to-day maintenance, as discussed within Chapter 5.0. 6-2

Case Study Inset 6-1: Selection of a Tool at the Asset Level When considering adopting a new condition assessment tool or technique, Sydney Water compares the effectiveness of the new tool with the current tool, if a tool is currently used. The comparison involves a cost-benefit evaluation per asset. Maintenance cost history for each asset is used as the fundamental benchmark. If a new tool will cost more, it still may be considered if it gives an earlier warning of failure. See Case Study 9 in Chapter 8.0. Figure 6-1. Process Flowchart for Developing Condition Monitoring Programs. Within the context of SAM, as noted previously, some utilities adopt an informal approach where condition and performance assessments are not yet undertaken or are undertaken in a somewhat unstructured manner. At the other end of the spectrum, more sophisticated asset management approaches do not focus on condition and performance, although condition monitoring is undertaken for specific assets where it is shown to be a useful approach to risk management (see Chapter 5.0) or where there is a regulatory driver to undertake the monitoring. The protocol adopted for tool selection in this research has been designed with all these potential end uses in mind, and is based on a process of exclusion according to a range of criteria, followed by an economic assessment of the viable alternatives. An overview of the approach is shown in Figure 6-2. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 6-3

Figure 6-2. Approach to Selecting Condition Assessment Tools. As illustrated in Figure 6-2, the selection of a suitable tool (step six of the process described in Chapter 3.0) requires consideration and evaluation of four factors: Technical feasibility: The utility identifies what inspection/assessment options are feasible for the asset(s) in question. Technical suitability: The utility evaluates whether the potential options will meet its specific needs, for example, by providing suitable data and/or level of decision support required. Technical capacity: The utility then evaluates if it possesses the required technical capacity to allow the potential options to be used and, if not, what the gaps in capacity are, including an initial assessment of whether these gaps can be filled. Economic assessment: The utility evaluates whether the remaining options add value based on the goals of the assessment, considering costs (including capacity building and/or out-sourcing of work) and benefits, and whether one approach clearly gives the best value compared to other available options. Final selection is made in terms of available resources, the cost-benefits accrued and affordability issues. 6.3 Exclusion Criteria According to the process described above, the selection of an appropriate inspection tool or assessment technique involves a criteria-based technical exclusion process. Necessary and/or desirable criteria are specified and tools approaches excluded based on their inability to satisfy these criteria. For example, the assessment of technical feasibility is based on asset-related criteria. Exclusion of tools on that basis provides a list of all feasible options for the asset type in question. The subsequent assessment of technical suitability and technical capacity allow the list 6-4

of feasible options to be reduced to a list of options that could be used by the utility. An economic appraisal allows this list to be ranked and the appropriate tool selected. A number of important criteria related to the first three steps of the exclusion process were identified to guide the selection of tools and techniques using the process illustrated in Figure 6-2. Two separate sets of criteria are presented herein: Criteria relating to inspection tools: these criteria relate to specific inspection tools and techniques, such as ultrasonic thickness gauges. Criteria relating to assessment tools: these criteria relate to asset management tools or condition assessment tools that use inspection and other data to characterize asset or system condition. Table 6-1 details the criteria for inspection tool selection and Table 6-2 details the criteria for selection of assessment tools. Various characteristics of a utility also influence what approaches to condition and performance assessment should be selected. Characteristics of significance are summarized in Table 6-3. 6.4 Application of Exclusion Protocol Where relevant information could be found, the attributes relating to the exclusion criteria detailed in Tables 6-1 and 6-2 have been evaluated for each of the tools and techniques identified and reviewed in this project. These attributes summarize the application and use of the tools and provide the information necessary to identify the range of tools and techniques that apply to the application under consideration. It is assumed that once a list of useable options is identified, the utility will undertake a cost-benefit analysis to select the appropriate tool. The factors shown in Table 6-3 influence this analysis, along with economic factors such as: The capital and operational costs associated with the inspection. Costs associated with analysis and interpretation of the inspection data. The accuracy and precision of the results. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 6-5

Table 6-1. Exclusion Criteria for Inspection and Survey Tools/Techniques. Category Selection criteria Notes Technical Assets covered What type of asset is covered by the tool? selection Material type What material is covered by the tool? Technical suitability Service area Access requirements Limitations relating to asset condition Limitations relating to asset size/geometry Continuous/discrete Destructive/non destructive Interruption to supply/function Assessment parameters Integration with software tools Potable or wastewater? Are there any specific access requirements (launch assemblies, power, etc.)? Is there a restriction if the asset is in bad condition (this includes presence or absence of lining/coating)? Is there a size/diameter restriction and is there a restriction in asset geometry? Does the technique give continuous/discrete readings (in time and space)? Is the asset (or part thereof) destroyed or is it a nondestructive test? Can the inspection be undertaken on-line or must the asset be taken off line? What is measured (defects, blockage, integrity, wall section, etc.)? Is the tool/approach stand-alone or can the output be integrated into utility systems easily (e.g., telemetered, up loading via mobile phones)? Utility technical capacity Commercialization of tool Previous/existing use of the tool in sector Accuracy/reliability Ease of validation of results Asset management sophistication required Skills required (level of tool sophistication), usability Technology required (level of tool sophistication) Documentation Availability of technical support Is the approach/tool fully developed? Can it be used off-theshelf? History of use in terms of uptake in the water and other sectors and acceptability to stakeholders? Any measure of accuracy (qualitative and/or quantitative)? Can the results be easily validated or are they indicative at best? Is the approach associated with high levels of asset management sophistication or can any utility use it? What level of operator skill is needed? What level of technological sophistication is needed (high power computers, sophisticated assets)? Is the tool documented? Are standards available? Is the tool supported (helpline or other point of contact)? 6-6

Table 6-2. Exclusion Criteria for Asset Management and Assessment Tools/Techniques. Category Selection criteria Notes Technical selection Technical suitability Assets covered Granularity Service area Focus of analysis Scalability of tool/approach Commercialization Previous/existing use of the tool Ease of validation Flexibility with respect to analysis (asset types) and granularity (system, asset level) What type of asset is covered by the tool? What level of detail is covered (asset level, area/zone, utility)? Potable or wastewater? What is assessed (remaining life, probability of failure, level of service, risk, etc.)? Is the tool/approach only suitable for small/large utilities? Is the approach/tool fully developed? Can it be used off the shelf? History of use in terms of uptake in the water and other sectors and acceptability to stakeholders? Can the results be validated? Is the tool flexible in terms of service or asset focus? Utility technical capacity Integration with other tools/gis Asset management sophistication In-house skills required Technology required Documentation Data Requirements Linking to asset data Availability of software and technical support Usability Can the tool be integrated with existing system? Is the approach associated with high levels of asset management sophistication or can any utility use it? What level of skill is needed (technician, engineer, etc.)? What level of technological sophistication is needed (high power computers, sophisticated networks)? Is the tool documented? Are standards available? What data are required by the tool? Does the tool provide facility to use TAG numbers or other asset identifications? Is the tool supported (helpline or other point of contact)? Is the approach considered useable? Table 6-3. Utility Criteria that Influence the Choice of Tools/Techniques. Attribute Size Location Service areas Data quality/quantity Technical development of asset stock Degree of asset management process development Available budgets Managerial commitment Network state Characteristics Large/medium/small (population served) Urban/rural/mixed Drinking/waste water, pipeline assets/non-pipeline assets Good/average/poor High (state-of-art)/average (mix)/low (obsolete) Well developed/developing/not developed Cash rich/cash poor Board-level commitment/engineers/etc. Good/mixed/near collapse Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 6-7

6.5 Development of a Prototype Expert System (ES) A key goal of this research was to provide a framework to assist a utility in the selection and use of condition assessment tools. A paper-based solution has been developed to facilitate this process (see Chapter 7.0). However, the complexity of tool selection, in combination with the number of tools and techniques used within the water sector, make such an approach unwieldy. The research team considers that a better approach is to incorporate the information and selection procedure within a software tool. After review of a number of options, an ES was identified as an appropriate vehicle for delivering the research outputs for the following reasons: Importantly from the perspective of the research, the development of the ES provided a focus for the development of the tool selection logic and criteria and guided the tool reviews and design of the paper-based selection process. Within the context of the research deliverables, an ES provides a user-friendly tool that helps a utility to identify tools and techniques appropriate to its needs. The ES also provides a means of organizing information in a way as to allow easy access. Unlike a purely paper based approach, an ES can be expanded and refined as new information becomes available and made available via the world wide web. With these issues in mind, initial development was undertaken of a prototype ES for this application, as described in Appendix E. 6.6 The Impact of Risk and Cost on Tool Selection The role of risk in determining the level of attention given to an asset has been discussed in various sections throughout this report. A direct extension of these risk-based arguments is that the more important the asset is (the higher the consequences of failure are), the more expense can be justified in assessments to ensure the asset does not fail. However, to minimize costs, inexpensive tools should still be used where possible. As such, the following can be stated: Inexpensive screening tools and approaches should be used routinely. The results of the screening approach may dictate that there is a need for additional information and/or accuracy. This may require the use of more sophisticated/accurate assessment or inspection tools. Additional expense should be considered only when justified in terms of risk costs avoided or benefits accrued. These basic guidelines led to the conclusion that, while there may be a range of tools and techniques available to inspect/assess a given asset, the utility should select the cheapest of any suitable options available that meets its immediate needs. Take, for example, the case of a large (>300 horsepower) centrifugal pump, for which the following condition monitoring techniques are feasible: Visual observation Performance monitoring (pump performance trending) Oil Analysis 6-8

Vibration analysis Bearing temperature trending Acoustic monitoring techniques Ultrasonic thickness measurement Infrared thermography Motor circuit analysis While it is useful to identify the tools that are feasible, the question still remains, which of the techniques should be applied? To help manage costs, the most inexpensive screening tools should be applied first. Therefore, since they are the cheapest monitoring techniques available, as a minimum, maintenance and operators should perform a routine monitoring role (e.g., listening for unexpected noise, making visual assessments of deterioration and providing feedback on performance issues to maintenance planners). When appropriate data capture systems have been set up (e.g., telemetry), trending of operational parameters should also be carried out routinely as part of condition monitoring and for energy efficiency purposes. Depending on the importance of the asset, and its operating context (e.g., whether there is any redundancy or significant levels of storage available), other condition monitoring tasks might be deemed necessary. Risk-based approaches like RCM provide a means of determining if a maintenance task is worth doing and at what interval inspections should be undertaken. In this example, it is likely that a utility would find it cost-effective to undertake periodic oil testing, vibration analysis of the pump and motor and trending of bearing temperatures. Once a trigger threshold has been detected by one of the routine monitoring approaches, some action needs to be taken. This action could be: A repair/replacement of a failing component. A change to the monitoring regime (to monitor the asset more closely to determine when a critical condition is reached or to provide information on the rate of deterioration). Additional inspections using other feasible, but more costly, techniques than those used for screening. The cost of any additional investigation should be in proportion to the cost of subsequent maintenance tasks. For example, if the inspection cost is a significant proportion of the maintenance task, then further investigation is only warranted under specific circumstances (such as the lead time for spare parts and the operational context means is desirable to continue to run the asset, but the level of risk associated with this decision needs to be understood). For other cases, it can be assumed that when averaged across a number of assets, carrying out the maintenance immediately, rather than undertaking additional investigation, would realize cost savings. In such circumstances, the utility may develop a policy for determining when to undertake additional investigations, in light of overall maintenance costs and operational experience. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 6-9

6.7 An Iterative Approach to Asset Assessments The example of the centrifugal pump given above can be generalized to give an iterative approach to the use of tools where increasing levels of sophistication are used that build upon the results of previous tools and assessments. In this approach, tools are initially selected that perform a screening function, for example, to identify the early signs of deterioration. More detailed inspection and analysis can then be performed to investigate the asset condition further, if and when justified. If an appropriate screening tool cannot be identified, it may be necessary to use a more sophisticated approach in the first instance. A similar approach to this was adopted by a company in the United Kingdom in the analysis of water transmission pipe failures, as summarized in Case Study Inset 6-2. The concept of a sliding scale of assessment standards presented in the case study is considered useful, especially when generalized to consider assessments undertaken for reasons other than failure investigation. Such an approach is outlined in Table 6-4. As shown in Table 6-4, the assessment standard applied is dictated by the type of asset (reactive or proactive), access considerations and the driver behind the assessment (condition monitoring, failure investigation, etc.). Case Study Inset 6-2: A Sliding Scale of Failure Investigations A water company in the United Kingdom is reported to have around 150 trunk main failures per year (Ham, 2006; personal communication). The failures vary in severity from near inconsequential to catastrophic involving millions of dollars of claims and litigation. To standardize its approach to failure investigations, the utility determined the level of investigation to be undertaken for a range of failure circumstances and mapped out criteria to allow operational staff to determine what level of assessment was to be undertaken given the particular circumstances of a failure. These ranged from opportunistic investigations undertaken at the time of the failure through to the use of expert test house and expert witnesses to investigate a failure and to contribute to legal proceedings. In essence, the approaches represent a sliding scale: Bronze: opportunistic investigations only. Silver: bronze level tasks plus additional investigations. Gold: silver level tasks plus additional investigations. Platinum: gold level tasks plus additional investigations. There is an increasing level of sophistication with increasing importance of the asset failure. At the highest level (platinum), cost is not considered an issue. As such, a range of techniques will be used, from opportunistic investigations through to expensive destructive tests undertaken and reported by experts. In general, it can be concluded that the more there is at stake, the greater the level of assessment that is justified. As in the example in Case Study Inset 6-2, the application of lower assessment standards should always precede higher assessment levels where possible. In 6-10

particular, opportunistic and routine assessments should be carried out as a precursor to more detailed assessments when practicable (see Case Study Inset 6-3). Standard Typical asset Table 6-4. Sliding Scale of Assessment Standards. Focus Sample Frequency Typical tools Accuracy Expertise Opportunistic Reactive Data collection Representative Opportunistic Visual Qualitative Operations Routine Proactive asset with access Regular inspection and/or routine monitoring undertaken to anticipate impending faults Asset specific Regular to continuous Visual, low cost screening Qualitative, low accuracy quantitative Maintenance specialist Bronze Proactive asset with some access restriction or deemed to be of concern due to age or condition Regular inspection and/or routine monitoring undertaken to anticipate impending faults, individual assessment for renewal planning Representative or asset specific Regular to continuous Higher end NDT Qualitative, low to moderate accuracy quantitative Engineer Silver Proactive assets with difficult access Individual assessment for renewal planning Representative or asset specific Infrequent Higher end NDT or DT High accuracy quantitative Consultant Gold Known problem asset with poor performance Individual assessment for renewal planning Asset specific Individual assessment Higher end NDT or DT High accuracy quantitative Specialist consultant Platinum Failed asset with potential or actual litigation associated with failure event Forensic investigation Asset specific Individual assessment High end NDT and DT, with lab tests as required Highest achievable accuracy Expert in field This concept is shown in Figure 6-3, which indicates that once initial condition and performance assessments have been undertaken, there is an explicit requirement to consider if the information gap has been filled, or if the decision being considered necessitates an increase in data quality or quantity. In the later case, additional assessments are undertaken, using more sophisticated tools and techniques, until the information gap is filled. In the case of large important assets where risk analysis (e.g., RCM or FMECA) shows that on-going condition monitoring tasks using sophisticated tools and techniques is justified, Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 6-11

opportunistic and routine assessments should still be carried out in conjunction with the more sophisticated techniques to improve the reliability of the overall asset monitoring. Case Study Inset 6-3: Water Corp s Approach to Assessment of Water Tanks Inspection of tanks by Water Corp is undertaken periodically under its asset condition assessment (ACA) program. Often, this is aligned with maintenance activities. Similarly, when emptied for cleaning, operators will undertake visual inspection. The tank site is divided into assessable elements for the purposes of condition assessment. Inspection templates are used to guide the inspector to assess the components of the tank that should be examined, for example, walls and floor, stand and roof to facilitate the capture of information about the appearance of the asset. More detailed or technical assessments are normally undertaken on the basis of some perceived need: 1) visual inspections reveal some issues (defects) that warrant further investigation, 2) issues with assets of a similar type have been identified or 3) it is known that visual inspection will be insufficient to identify defects for example, under floor corrosion. A range of non-destructive techniques can be used in these assessments, including: Magnetic flux leakage floor scanners to scan floor plates. Ultrasonic sensors (to evaluate floor scanner results, and to test walls and areas of floor not accessible to the floor scanner). Concrete cover meter. See Case Study 4 in Chapter 8.0. Figure 6-3. Iterative use of Condition and Performance Assessments. 6-12

The cost of inspection should be considered in light of the cost of subsequent tasks, such as repair or replacement. For example, if the cost of inspection is likely to be a significant proportion of the cost of replacement, it could be more cost effective to just to replace the asset. In this context, Elliot et al (AwwaRF, 2001) noted that prior to initiating test procedures on electric motors, it is necessary to compare the cost of replacing the motor to the cost of the testing. For some small commodity size (less than 25Hp) motors, it is cheaper to replace them than to completely evaluate and repair them. Motors that are 25 Hp and larger may or may not be cheaper to replace outright instead of evaluating and repairing. Even for high consequence assets, the cost of the condition assessment should be considered in light of the cost of subsequent maintenance tasks. Given the impact on risk and operational budgets, it is up to individual utilities to determine what they consider to be an appropriate balance between the cost of further investigation and the cost of subsequent maintenance tasks. In some cases, an asset type known to be performing poorly can be replaced opportunistically, without any further consideration of the asset condition, because over a number of assets this approach will accrue benefits for the utility. For example, see Case Study Inset 6-4. Case Study Inset 6-4: Bellevue s Asbestos Cement Pipe Replacement Program Bellevue council determined that its asbestos cement (AC) pipes were in poor condition through on-going review of failure data; over the last nine years, roughly 69% of the main breaks occurred in AC pipes. Due to this high failure rate, an AC pipe replacement program is underway; pipes are replaced when breaks occur and/or when the roadways are resurfaced. This replacement was undertaken without any additional condition assessment of the pipe. See Case Study 10 in Chapter 8.0. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 6-13

CHAPTER 7.0 AVAILABLE TOOLS AND TECHNIQUES Chapter Highlights The categorization of assets used in this project to allow tools and techniques to be mapped on to the asset stock is: Service Area: clean, waste; then Pipeline assets: valves, meters, fittings and pipes, or Non-pipeline assets: mechanical, electrical, ICA, civil and building. A summary table is provided showing the applicability of various tools and techniques in terms of these asset categories and other selection criteria. The selection process is summarized as follows: 1. Determine technical feasibility; determine the part of the selection table that is appropriate to the application under consideration. 2. Review summary information; to identify techniques that could be used. 3. Review each of the potential tools; refer to the detailed write up in Appendix F and consider the information presented. 4. For viable options undertake cost-benefit analysis; with due consideration given to the accuracy of the tool, the level of asset risk and the available budgets. Protocols for Assessing Condition and Performance of Water and Wastewater Assets 7-1

7.1 Introduction A large range of condition assessment tools and techniques can be applied to different water and wastewater service areas and to different parts of the asset stock. These include inspection tools, environmental surveys and condition monitoring techniques. In presenting the available tools and techniques, it is necessary to first consider how to categorize the asset stock and then to map the available tools and techniques onto this representation. This chapter describes the categorization of the asset stock adopted in this project. The various condition and performance assessment techniques identified are then mapped onto this representation. This mapping is then developed to provide a tabular approach to initial selection of tools/techniques by asset type, in line with the selection protocol detailed in Chapter 6.0. 7.2 Representation of the Asset Stock Various approaches are used to categorize asset stocks in different sectors. For example, the categorization of assets used in the International Infrastructure Management Manual (IPWEA, 2006) is given in terms of static and dynamic assets. The Manual applies to a range of sectors, including roads, electricity, water supply, property, wastewater and gas. Given the range of sectors (and thus asset types) considered in the Manual, categorizing the asset stock as dynamic and passive is an effective way of dealing with the range of asset types covered. However, given that the current project is focused on one sector, it is more logical to consider the asset stock in terms of the two main service areas - water and wastewater. It is also natural to consider discrete non-pipeline assets and distributed pipeline assets separately. Discrete assets are generally above ground, contained within a given site, more accessible and easier to assess than pipeline assets. In contrast, pipeline assets are spatially distributed, generally below ground and more difficult to access and assess. Various other descriptors can be used to help describe the asset under consideration. The representation of the asset stock used in this project is presented in Tables 7-1 and 7-2. As indicated in the tables, assets are categorized according to unit type; a unit being defined as a sub-system of a larger asset or a section of pipeline considered separately for asset management purposes. For above ground (non-pipeline assets), units are categorized as: Mechanical and electrical (M&E) assets. Civil and building (C&B) assets. Instrumentation, control and automation (ICA) assets. 7-2

Table 7-1. Service Area: Water Supply. Asset category Asset Unit* definition by Other descriptors Pipeline Abstraction meters - Size, type (below ground) Raw water (non potable) conduits Pipe lengths, fitting Material, diameter, pumped Bulk water meters - Size, type Transmission pipes Pipe lengths, fitting Material, diameter, pumped District meters - Size, type Distribution pipes Pipe lengths, fitting Material, diameter Commercial meters - Size, type Service pipes Connection Material, diameter Domestic meters - Size, type Valves (block/stop, pressure reducing, etc.) - Size, type, open/closed Air valves - Size, type Non-pipeline (above ground) Hydrants - Size, type Dams and impounding reservoirs M&E, C&B, ICA Size, type Source pumping stations (including bore holes) M&E, C&B, ICA Capacity, type Raw water intakes M&E, C&B, ICA Size, type Raw water storage M&E, C&B, ICA Size, type Intake (works) pumping stations M&E, C&B, ICA Capacity Treatment works M&E, C&B, ICA Size, source-type, process/complexity Booster pumping station M&E, C&B, ICA Capacity Service reservoirs M&E, C&B, ICA Size, configuration Water towers M&E, C&B, ICA Size, configuration Other civil structures (roads, walls, etc) - Use Buildings - Use *A unit is considered to be a sub-system of a larger asset or a section of pipeline considered separately for asset management purposes. Note: M&E: Mechanical and Electrical; C&B: Civil and Building; ICA: Instrumentation Control and Automation Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 7-3

Table 7-2. Service Area: Wastewater Collection and Disposal. Asset category Asset Unit* definition By Other descriptors Pipeline Laterals (service connections) Connection Material, diameter (below ground) Non-critical sewers Pipe lengths, fitting Material, diameter, depth Critical sewers Pipe lengths, fitting Material, diameter, depth Man holes - Material, diameter, depth Valves (block/stop, etc.) - Size, type, open/closed In-line (underground) storage - size, type Force mains Pipe lengths, fitting Material, diameter, pumped Air valves - Size, type Surface water outfalls - Material, diameter CSOs - Design, size Non-pipeline (above ground) Marine outfall - Material, diameter, length Pumping stations M&E, C&B, ICA Capacity Detention tanks M&E, C&B, ICA Size Treatment works M&E, C&B, ICA Size, process/complexity Storm water storage M&E, C&B, ICA Size Sludge treatment works M&E, C&B, ICA Size, disposal route Other civil structures (roads, walls, etc) - Use Buildings - Use *A unit is considered to be a sub-system of a larger asset or a section of pipeline considered separately for asset management purposes. Note: M&E: Mechanical and Electrical; C&B: Civil and Building; ICA: Instrumentation Control and Automation. 7.3 Mapping Tools onto the Asset Stock As noted in previous Chapters, when designing an assessment program, one of the key steps is to identify tools and approaches that can be used for the asset types under consideration. A key selection criterion is thus the type of asset that can be assessed by a tool/technique. Tool selection can be facilitated by mapping the tools onto a categorization of the asset stock. In line with Tables 7-1 and 7-2, a logical approach is to map available tools onto the asset stock categorized in terms of the main divisions of assets, namely, pipeline/non-pipeline assets. 7.3.1 Mapping for Pipeline Assets For pipeline assets, the mapping of tools is relatively straightforward, because various characteristics of the assets given in Tables 7-1 and 7-2 constrain tool selection; for example, the number of tools under consideration can be reduced according to: Service area (potable or wastewater). Hierarchical considerations (whether pipe or networks are being considered). Asset type (whether pipe, fitting, valve or meter). Asset size (many approaches used for larger mains are not suitable for smaller pipes). In the case of pipes and fittings, material type (for example, some approaches used for cementituous pipes are not suitable for plastic or ferrous pipes). The approach to mapping tools onto assets adopted herein is simply to define the relationship between the tools and assets categorized in these ways. 7-4

7.3.2 Mapping for Non-Pipeline Assets Mapping of tools onto non-pipeline assets is not so straightforward because of the range and type of assets used within the sector. Complex assets, such as wastewater and water treatment facilities, are however often categorized in terms of an asset hierarchy. The hierarchies used by utilities differ in detail, but follow the same overall logic, namely, dividing a discrete facility into distinct parts according to the needs of the management system. For example, Table 7-3 shows a range of hierarchies used in the sector. Table 7-3. Hierarchical Representations for Complex Assets. Level 1 Level 2 Level 3 Level 4 Level 5 Level 6 Site Stage Sub-stage Unit Component Assembly Facility System Subsystem Unit Component - Facility - Sub-facility Unit - - Notes: 1) Component in this context means the mechanical, electrical and civil component of the unit. 2) Unit is often considered to be an asset that does a defined job and is large enough to be included as a separate item in a renewal program. The use of hierarchies is an important feature of asset management information systems. While the asset hierarchy has an important bearing on the design of an assessment program, especially when designing grading systems (see Chapter 3.0), this hierarchical representation of the asset stock has no direct bearing on the mapping of inspection tools and techniques, because most tools are used at the lower end of the hierarchy (at the unit level, component level or lower). One potential approach to mapping tools and techniques onto the asset stock would be to expand the hierarchy to identify all the assessable assets within a utility s operations and to subsequently map the tools and techniques onto these assets. Table 7-4 shows how the asset hierarchy for a clarifier is expanded. When expanded in this way, the number and variety of components becomes clear; there are a significant number of assessable components within just this one asset type. As such, mapping inspection devices onto all the asset types involved in delivery of water and wastewater services was not considered practicable. One alternative considered was to select just a few key assets and determine the tools applicable to them. However, given the fact that the specific assets of interest will vary over time and between different utilities and sector professionals, this approach was considered too limiting. An alternative simplified approach to categorization of the asset stock was therefore sought. During the initial phase of the research, it became clear that exact type of asset does not have a great bearing on the selection of condition and performance assessment tools, techniques or approaches. Of more use is the categorization of assets lower in the asset hierarchy. A useful categorization that is already applied within the water sector is: Civil and building (C&B) assets. Instrumentation, control and automation (ICA) assets. Mechanical and electrical (M&E) assets. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 7-5

Using this approach, the hierarchical representation given in Table 7-4 reduces to that given in Table 7-5. Table 7-4. Hierarchical Representations for Complex Assets. Facility System Subsystem Units Components Water treatment plant Water treatment Clarifier Basin Access hatches, ladders, rungs, stairs Coating system Drain Floor Foundation Gratings Handrail Launder supports Launders Tray Walls; baffle Walls; structural Gates/actuators Weirs Actuator Body Frame Seals/seats Stem/operator (manual) Clarifier Mechanism Trim High torque cutouts/controls Associated electrical support system Baffles Corner sweeps Drive Gear box Motor Rake arm Table 7-5. Hierarchical Representations for Complex Assets. Facility System Subsystem Units Components Water treatment Water treatment plant system Basin Civil Clarifier Gates/actuators Mechanical Clarifier mechanism Mechanical, electrical This simplified asset categorization of asset components was used to allow the tools and techniques available to be mapped onto the asset stock. The selection of tools and techniques therefore depends on: The type of component in question (whether mechanical, electrical, etc.). A range of selection criteria (used to refine the potential list of techniques). The relative cost of the condition assessment, relative to the benefits accrued. 7-6

7.4 Tool Selection Process As noted in Chapter 6.0, the selection of tools and techniques is a complex issue, involving review of a significant amount of information and consideration of a range of factors. A prototype expert system developed in this project (see Appendix E) was intended to facilitate this selection process, but there is still a need to represent the information within this report. A manual selection process has therefore been developed, which is based on a tabular summary of the tools reviewed and includes a few of the key selection criteria, as presented in Table 7-6. The selection process using Table 7-6 is summarized as follows: Step 1. Determine technical feasibility: identify the part of Table 7-6 that is appropriate to the application under consideration. Step 2. Review summary information: identify techniques that could be used. Step 3. Review each of the potential tools: refer to the detailed write up in Appendix F and consider the information presented. Step 4. Undertake cost-benefit analysis for viable options: with due consideration given to the accuracy of the tool, the level of asset risk and the available budgets. For example, consider a user that is interested in the inspection of a wastewater pump, which is both a mechanical and electric asset. For simplicity, consider the mechanical aspect only. The user would turn to the part of Table 7-6 relating to Non-Pipeline Assets; Mechanical assets. The service area of interest is wastewater, which in this case does not exclude any of the inspection techniques. The remainder of the selection criteria includes: Assets covered Assessment (what is measured) Access requirements Service interruption Accuracy Commercialized Skills required From a brief review of the remainder of the attributes, it is clear that the techniques under consideration are: 1) oil testing, 2) performance testing and 3) vibration analysis. A review of the descriptions of these techniques (given in Appendix F), indicates that each of these techniques is still feasible. Cost-benefit analysis would therefore be required, which necessitates obtaining information from venders. However, it is again stressed, that this analysis should be undertaken within a risk-informed framework, such as those described in Chapters 5.0 and 6.0, which balances cost of inspection/monitoring against the risks of failure. This approach is focused on the selection of a tool to undertake the condition assessment. The use of grading schemes and performance monitoring could also be selected, depending on the requirements of the assessment program. The reader is referred to the sections on these approaches (for condition grading, see Chapter 3.0; for performance monitoring, see Chapter 5.0). Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 7-7

Table 7-6. Tool and Technique Selection Tables. Tool or technique Barcol hardness Service type Waste and potable Assets covered NA Material Assessment Service interruption Plastics and Material NA cementituous hardness Accuracy Commercialized Skills required Semiquantitative Yes widely available Basic Non-destructive Carbonation testing and petrographic examination Corrosion burial test Schmidt hammer Waste and potable Waste and potable Waste and potable NA Cementituous Depth of carbonation in mm NA Ferrous Soil corrosivity NA Concrete and Compressive brick strength NA Quantitative Yes widely available Basic NA Relative - Basic NA Quantitative Yes widely available Basic Pipeline assets Physical property testing Pipe sample tests - Destructive Condition assessment of plastic pipes Core/coupon sampling Cut-out sampling Fracture toughness C-ring Indirect tensile strength test Methylene chloride gelation Pit depth measurement Waste and potable Waste and potable Waste and potable Waste and potable Waste and potable Waste and potable Waste and potable Pipes Plastics Material properties Off line on sample Pipes Any - Cores can be taken under pressure Quantitative NA dependent on test Through Testing Labs NA dependent on test Pipes Any - Off-line NA NA dependent on test Pipes PVC Fracture Off line on Quantitative Through Testing toughness sample Labs Pipes AC and Tensile Off line on Quantitative Through Testing Conc. strength sample Labs Pipes PVC Level of Off line on Qualitative Through Testing gelation sample Labs Pipes Ferrous Pit depth to Off line on Quantitative Yes widely infer rate of sample available corrosion Specialized skills NA dependent on test NA dependent on test Specialized skills Specialized skills Specialized skills Basic Phenolphthalein Indicator Waste and potable Any cementituous Cementituous Carbonation depth Off line on sample Qualitative Yes widely available Basic Slow crack growth resistance Waste and potable Pipes PE Resistance to slow crack growth Off line on sample Quantitative Mostly applied as research tool Specialized skills 7-8

Pipeline assets Inspection technique In-pipe (man entry) Tool or technique Active acoustic inspection Barcol hardness Carbonation testing and petrographic examination Cover meter Electrical potential (half cell) Man entry inspection Pull-off adhesion testing Schmidt hammer Service type Waste and potable Waste and potable Waste and potable Waste and potable Waste and potable Waste and potable Waste and potable Waste and potable Assets covered Material Assessment Service interruption Access Commercialized Skills required Pipes Cementituous Presence of Man entry Man entry Yes widely Tool training defects available required, with confined space Pipes Plastics and Material Man entry Man entry Yes widely Basic with Cementituous hardness available confined space Pipes Cementituous Depth of Man entry Man entry Yes widely Basic with carbonation available confined space in mm Concrete assets All reinforced concrete Reinforced concrete assets Reinforced concrete Cover depth to reinforcement Detection of corrosion Pipes Any Qualitative assessment of condition Coated assets Pipes Any coated assets Concrete and brick Adhesive strength of applied coatings Compressive strength Man entry Man entry Yes widely available Man entry Man entry Yes widely available Man entry Man entry Yes widely available Man entry Man entry Yes widely available Man entry Man entry Yes widely available Basic with confined space Basic with confined space Basic with confined space Basic with confined space Basic with confined space Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 7-9

Pipeline assets Inspection technique In-pipe (non-man entry) Tool or technique Broad band electro magnetic Service type Assets covered Material Assessment Service interruption Potable Pipes Steel, cast Remaining Off line as iron and wall pipe needs to ductile iron thickness be depressurized Structural Low flow or condition offline for qualitative pressurized assessment pipes CCTV Mostly waste Pipes Any (less useful for plastics) Fiberscope inspection In-pipe acoustic inspection tools (sonar) In-pipes Waste and potable Waste and potable Pipes Any Qualitative assessment of condition Pipes Any Pipe defects and geometry hydrophones Intelligent pigs Potable Pipes More suited to steel Magnetic flux leakage Potable Pipes Any Leak detection Geometry or corrosion Waste and potable Pipes Iron and steel Online or off line On line On line May cause water quality issues Access Commercialized Skills required Full bore access Internal use; mostly limited to assets 90mm Entry point (e.g., tapping) Access to pipe interior is required Large diameter mains Mostly large diameter mains specialized insertion point Metal loss Off line Available for external and internal use direct access to pipe wall required Yes Yes widely available Yes widely available Yes widely available Yes Limited use in water sector Yes - specialist consultants Specialist service Interpretation requires specialist skills Interpretation requires advanced skills Interpretation requires specialist skills Specialist service Specialist service Specialist service 7-10

Pipeline assets Inspection technique In-pipe (non-man entry) Tool or technique Multi-sensor pipe inspection robots Passive acoustic inspection Remote field eddy current Smart Digital Sewer Pipe Diagnostic System (VTT) Service type Assets covered Material Assessment Service interruption Mainly waste Pipes Any Depends on Depends on sensors used sensors used Waste and Pipes On line potable Waste and potable Pipes Prestressed concrete (PCCP) Iron, steel and prestressed concrete (PCCP) Detect failures of prestressed wires Internal or external defects Waste Pipes Any Automated analysis of defects Smoke testing Waste Gravity sewer Any Indicates illegal connections Off line On line On line Access Commercialized Skills required Access to pipe interior Access required for hydrophone entry Cut-ins required; pipes >150mm diameter Scanner inserted not suited to small diameter pipes Manhole access to sewer No under development Yes tool available from commercial supplier Yes - specialist consultants No under development Yes equipment available Advanced Training required for tool use result analysis requires expert Advanced skills for interpretation tool applied by specialist Advanced Basic Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 7-11

Tool or technique Acoustic emission Active acoustic inspection Barcol hardness Service type Waste and potable Waste and potable Waste and potable Assets covered Material Assessment Service interruption Access Commercialized Skills required Pipes Any Detection On line NA Yes Operator training and location commercially is required of material available from defects selected vendors Pipes Cementituous Presence of Off line and Access to Yes widely Tool training defects dewatered asset surface available required Pipes Plastics and Material On line Direct access Yes widely Basic cementituous hardness to pipe surface available Pipeline assets Inspection technique On-pipe Broad band electro magnetic Carbonation testing and petrographic examination Cover meter Drop test Electrical potential (half cell) Potable Pipes Steel, cast iron and ductile iron Waste and potable Waste and potable Waste and potable Waste and potable Remaining wall thickness Pipes Cementituous Depth of carbonation in mm Concrete assets Reinforced concrete assets Cover depth to reinforcement Pipes Any Water loss from pipe All reinforced concrete Reinforced concrete Detection of corrosion Off line as pipe needs to be depressurized On line On line Off line On line Exposure of pipe surface Direct contact with concrete surface Direct access to pipe surface Access to monitoring points Direct access to pipe surface Yes Yes widely available Yes widely available General approach Yes widely available Specialist service Basic Basic Basic Basic Holiday detector Waste and potable Coated assets Ferrous and concrete assets with coating for corrosion protection Location of defects in asset coatings Off line if internal coating is to be tested Direct contact with coating Yes widely available Basic technical skills 7-12

Pipeline assets Inspection technique On-pipe Tool or technique Leak detection Including acoustic, tracer gas and infrared photography Linear polarization resistance Magnetic flux leakage Measurement of strain Service type Assets covered Material Assessment Service interruption Potable Pipes Any Leak On line effectiveness detection depends on technique Waste and potable Waste and potable Waste and potable Buried ferrous assets Results relate to ferrous assets Soil linear polarization resistance (LPR) On line Access Commercialized Skills required Most tests require access to pipe Access to soil at point of interest Pipes Iron and steel Metal loss Off line Direct access to pipe wall required Any component made of homogenous material NA Stress and strain analysis On line Access to surface Yes tools widely available and applied Equipment is widely available Yes - specialist consultants Yes commercially available Dependent on technique used Operator training required Specialist service Engineer trained in operation of tool On-line leak detection systems Passive acoustic inspection Pit depth measurement Potable Pipes Any Change in flow parameters that indicates leak Waste and potable Waste and potable Pipes Prestressed concrete (PCCP) Detect failures of prestressed wires Pipes Ferrous Pit depth to infer rate of corrosion On line NA Developed for oil and gas sector, not yet widely applied in water sector On line Can be on line when done in-situ Exposed surface for accelerometer Quantitative Yes tool available from commercial supplier Yes widely available Automated monitoring (sophisticated tool) Training required for tool use result analysis requires expert Basic Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 7-13

Pipeline assets Inspection technique On-pipe Tool or technique Pipe potential survey Radiographic testing Schmidt hammer Ultrasonic measurement continuous (guided wave) Service type Waste and potable Assets covered Material Assessment Service interruption Pipes Ferrous Measures On line electrical potential between pipe and soil to infer corrosion potential Changes in Off line as material water absorbs structure radiation (inclusions, voids and corrosion) Potable Pipes Ferrous, cementituous and plastics (not GRP) Waste and potable Waste and potable Pipes Concrete and brick Compressive strength Pipes Iron and steel Level of wall thickness and corrosion pit depth On line On line Access Commercialized Skills required Electrical contact with asset is required Access required to both sides of pipe Direct access to pipe surface Direct contact required with pipe wall Yes- available from commercial suppliers Yes tool and service commercially available Yes widely available Yes Specialist training required Advanced requires specialized contractor Basic Basic tool operation Advanced analysis of results Ultrasonic measurements - discrete Visual inspection Waste and potable Waste and potable Pipes Iron and steel Level of wall thickness and corrosion pit depth All Any Qualitative visual assessment On line On line Direct contact with asset - surface must be smooth and clean Physical access required Yes widely available NA Trained technician Interpretation requires training 7-14

Pipeline assets Inspection technique Meter Valve Tool or technique Visual inspection (see notes on water meters in Table 3-3) Volumetric X-ray or radiographic testing CCTV Fibrescope inspection Radiographic testing Service type Waste and potable Waste and potable Mostly waste Waste and potable Assets covered Material Assessment Service interruption Meter NA Qualitative On line visual assessment Welded joints, castings, electronic assets, etc. Metal Integrity of assets Valves Any Structural condition qualitative assessment Valves Any Qualitative assessment Potable Valves Ferrous, cementituous and plastics (not GRP) of condition Integrity of assets Valve exercising Potable Valves NA Valve condition and operability Visual inspection Waste and potable Valves NA Qualitative visual assessment Off line for laboratory testing or when meter interior is assessed Low flow or off line for pressurized pipes On line or off line Off line as water absorbs radiation On line On line Access Commercialized Skills required Physical access required Direct access required to asset Internal use; mostly limited to assets 90mm Entry point (e.g., tapping) Direct access required to asset Physical access required Physical access required NA Yes commercially available from selected vendors Yes widely available Yes widely available Yes tool and service commercially available Equipment required widely available NA Interpretation requires operator training Advanced requires specialized contractor Interpretation requires training Interpretation requires training Advanced requires specialized contractor Basic operator needs training Interpretation requires operator training Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 7-15

Pipeline assets Strategic planning Tool or technique Service type Assessment focus Data needs Commercialized Integration Skills required Asset management sophistication AQUA-Selekt Waste Sewer condition CCTV inspection data AQUA-WertMin Waste Planning of CCTV inspection, rehabilitation and construction for sewer networks CARE-S Waste Service levels, budget setting, life cycle cost and rehabilitation planning CARE-W Potable Service levels, budget setting, life cycle cost and rehabilitation planning FailNet Stat Potable Failure forecasting model for water pipelines KANEW Potable Strategic tool that estimates length of water mains to replace or repair each year KureCAD Waste Applies GIS analysis for prioritization of sewer rehabilitation PARMS Planning Potable Long term asset management planning using asset failure curves developed from utility data Requires CCTV data Dependent on models applied Dependent on models applied Good asset and failure data needed Good asset and failure data desirable Good GIS data required Good asset and failure data needed Yes has had limited application in Europe Yes available from Germany; limited application No research applications only No some application in European cities No only research application in Europe Yes basic version available through AwwaRF No standalone tool No standalone tool No standalone tool No standalone tool No standalone tool No standalone tool Professional engineering skills Professional engineering skills Professional engineering skills Professional engineering skills Professional engineering skills Professional engineering skills Yes Links to GIS Professional engineering skills Yes used by a number of Australian utilities No standalone tool Professional engineering skills Basic to advanced Basic to advanced Basic to advanced Basic to advanced Basic to advanced Basic to advanced Basic to advanced Basic to advanced 7-16

Tool or technique Service type PARMS Priority Potable Decision support system to assist in asset renewal decisions Assessment focus Data needs Commercialized Integration Skills required Asset management sophistication Good asset and failure data needed Yes used by a number of Australian utilities No standalone tool Professional engineering skills Basic to advanced Pipeline assets Network assessment Strategic planning Hydraulic Assessment PiReP/PiReM Potable Decision support system for rehabilitation planning of water networks SCRAPS Waste Expert systems that prioritizes sewer inspections UtilNets Potable Reliability based decision support system for managing pipeline maintenance WARP Potable Long term asset management planning using asset failure curves Good asset and failure data needed Information on critical assets Good asset and failure data needed Good asset and failure data needed FailNet-Reliab Potable Hydraulic reliability Good asset and failure data needed Hydraulic modeling Inflow and infiltration sewer flow survey Potable and waste Waste Relationships between flow, pressure, roughness, capacity and service Inflow and infiltration to sewers High good quality asset data needed High No under development with commercial release planned Yes available from WERF No currently at prototype stage Yes planned release in 2006 No only limited research application Yes many commercial and public domain software available NA framework approach Leak detection Potable Detection of leaks NA Tools widely available No standalone tool No standalone tool No standalone tool No standalone tool No standalone tool Can link to GIS Potential to link with GIS and hydraulic models NA Professional engineering skills Professional engineering skills Professional engineering skills Professional engineering skills Professional engineering skills Professional engineering skills Professional engineering skills Operator training required Basic to advanced Basic to advanced Basic to advanced Basic to advanced Basic to advanced Basic generic approach Basic generic approach Basic generic approach Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 7-17

Pipeline assets Network assessment Network Condition Environmental Survey Tool or technique Service type Assessment focus Data needs Commercialized Integration Skills required Asset management sophistication NA Operator Moderate Leak detection Potable Detection of leaks NA Tools widely available WRc sewer Waste Framework rehabilitation available as man manual WRc trunk main structural condition assessment Ground penetrating radar Linear polarization resistance Pipe potential survey Soil characterization Soil corrosivity Soil resistivity survey Potable Waste and potable Waste and potable Waste and potable Waste and potable Waste and potable Waste and potable Cost effective management of assets; identify service problems in drainage areas Current structural condition and remaining service life of water transmission pipes Location of buried assets LPR gives indication of soil corrosion rate for buried ferrous assets Measures electrical potential between ferrous pipe and soil to infer corrosion potential Soil parameters relevant to deterioration of buried assets Predicts corrosion rate for ferrous assets from soil characteristics Indication of soil corrosion potential for buried ferrous pipeline assets High but can be customized to be affordable Moderate Minimal data requirements NA NA NA Pipe characteristics NA Framework available as manual Yes- available from commercial suppliers Yes- equipment available from commercial suppliers Yes- available from commercial suppliers Equipment and testing services widely available Testing services widely available Equipment and testing services widely available training required NA High professional engineering skills NA High professional engineering skills NA Requires trained operator Results can be input to GIS Results can be input to GIS Results can be input to GIS Results can be input to GIS Results can be input to GIS Requires trained operator Specialist training required Operator training; interpretation requires expert Requires trained operator Requires trained operator Basic generic approach Basic generic approach Basic generic approach Basic generic approach Basic generic approach Basic generic approach Basic generic approach Basic generic approach 7-18

Tool or technique AwwaRF s Manager Software Service type Potable Assets covered Water treatment works Assessment Treatment work condition and value Access requirements Service interruption Accuracy Commercialized Skills required NA NA NA Available from Professional AwwaRF asset manager/ engineer Non-pipeline assets Electrical assets Current monitoring Ductor testing Insulation test Waste and potable Waste and potable Waste and potable Electric motors Electrical connections, busbars and contacts Motor winding, cables, switchboards and motor control centers Measurement of current in a circuit and comparison with design loads Determines the contact resistance in draw out contacts such as circuit breakers Electrical insulation performance No Access to normally live parts Access to conductor and insulation On-line with safety precautions in place Good comparison with historical recordings can be used to identify onset of faults Yes Off-line Good Yes widely available Off-line Equipment needs to be isolated Good accuracy Yes widely available Electrician required Trained electrical technicians or engineers Trained electrical technicians or engineers Load rejection test Motor circuit analysis Waste and potable Waste and potable Power generation systems Electric motors Performance of power generation systems under these sudden load changes Detection and monitoring of electrical motors and circuits Site specific On-line Dependent on approach No portable hand-held equipment Widely available in other sectors Off-line Good accuracy Yes widely available High team of engineers Trained electrical technicians or engineers Oil testing Waste and potable Mechanical assets with oil as lubricant or coolant Impurities and dielectric strength of oil, which may indicate asset condition Sample of oil required Dependent on equipment Oil analysis is accurate, but only indicative of asset condition Yes commercially available Laboratory analysis Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 7-19

Tool or technique Process control system (integrated) Service type Waste and potable Assets covered Networked instrumentation or electrical equipment Assessment Monitors assets and provides preventive maintenance data Access requirements Assets connected to field bus network Service interruption On line Accuracy Commercialized Skills required Dependent on measured variable Yes widely available Trained operator can assess condition data Non-pipeline assets Electrical assets Thermographic testing Transformer circuit protection coordination Transient earth voltage Waste and potable Waste and potable Waste and potable All electrical assets High value electrical assets All electrical assets Infrared imagery to locate defects and potential failures by scanning for thermal abnormalities Testing of electrical protective systems Detects discharges to earth through voids or insulation breakdown Direct access to live assets Access to high voltage areas No requirement for direct contact On line Qualitative Yes Field service engineer Off line power supply disruptions On line Indicative tool Yes Field service engineer Qualitative inspection tool Yes Field service engineer Ultrasonic emission inspection Visual Inspection Waste and potable Waste and potable Electrical assets such as switchboards Electrical assets Identify ultrasound waves that can indicate defects or failures Qualitative visual assessment; can include grading system (see section 3.3) Physical contact required to outer casing Physical access required On line Qualitative inspection tool Yes Field service engineer On line Qualitative NA Operator training required 7-20

Tool or technique AwwaRF s Manager Software Service type Assets covered Assessment Access requirements Service interruption Accuracy Commercialized Skills required Potable Water treatment works Treatment work NA NA NA Available from Professional condition and AwwaRF asset manager/ value engineer Non-pipeline assets Mechanical assets Measurement of strain Oil testing Performance testing of rotating machinery Process control system (integrated) Thermographic testing Ultrasonic emission inspection Waste and potable Waste and potable Waste and potable Waste and potable Waste and potable Waste and potable Any component made of homogenous material e.g., motor shaft Mechanical assets with oil as lubricant or coolant Pumps, fans, motors, air blowers, mixers, etc. Networked instrumentation or electrical equipment All electrical assets Electrical assets such as switchboards Measurement of strain Impurities and dielectric strength of oil, which may indicate asset condition Performance of rotating machinery, such as head, pressure, noise and vibration Monitors assets and provides preventive maintenance data Infrared imagery to locate defects and potential failures by scanning for thermal abnormalities Identify ultrasound waves that can indicate defects or failures No specific requirements Sample of oil required No specific requirements Assets connected to field bus network Direct access to live assets Physical contact required to outer casing On line Accurate Yes commercially available Dependent on equipment On line On line Oil analysis is accurate, but only indicative of asset condition Dependant on the accuracy of measuring device Dependent on measured variable Yes commercially available Yes Yes widely available Engineer trained in operation of tool Laboratory analysis Operator requires training for interpretation of results Trained operator can assess condition data On line Qualitative Yes Field service engineer On line Qualitative inspection tool Yes Field service engineer Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 7-21

Non-pipeline assets Mechanical assets Tool or technique Vibration analysis Visual Inspection Volumetric X- ray or radiographic testing Service type Waste and potable Waste and potable Waste and potable Assets covered Assessment Access requirements Rotating machinery, Condition fault Fixed point such as pumps, diagnosis by testing to ensure electric motors and measurement and consistent fans analysis of measuring point vibration Electrical assets Welded joints, castings, electronic assets etc. Qualitative visual assessment; can include grading system (see section 3.3) Non-destructive method used for checking the integrity of metal assets Physical access required Unobstructed view of area of interest Service interruption Accuracy Commercialized Skills required On line Qualitative Yes fully Field service assessment developed and engineer based on commercially comparison available with previous tests On line Qualitative NA Operator training required Off-line for laboratory testing Accuracy dependent on operator expertise Yes commercially available from selected vendors Operator requires training for image interpretation 7-22

Tool or technique Acoustic emission Service type Waste and potable Assets covered Assessment Material Service interruption Storage tanks, Detection and Any On-line Qualitative pressure vessels, location of material estimates of aerial lift devices, defects material welded joints damage Accuracy Commercialized Skills required Yes commercially available from selected vendors Operator training is required Non-pipeline assets Civil and Building Assets Air permeability AwwaRF s Manager Software Barcol hardness Carbonation testing and petrographic examination Concrete electrical resistance Core sampling Waste and potable Concrete elements with flat surfaces (slabs, walls, pavements, etc.) Permeability, quality class and capillary suction of concrete Potable Water treatment works Representing asset and condition data within a consistent framework Waste and potable Waste and potable Waste and potable Waste and potable Pipes Material hardness Plastics and cementituous Tanks, walls, dams, buildings, etc. Tanks, walls, dams, buildings, etc. Civil assets Presence of carbonation to determine concrete quality and protection of steel reinforcements Corrosion rate of reinforcement bars in concrete Sample core taken for analysis and testing Concrete On line Excellent measure of resistance of concrete against aggressive media Yes limited use in water sector NA NA NA Available from AwwaRF Reinforced concrete assets Reinforced concrete assets Reinforced concrete assets On line Semiquantitative Yes widely available Basic technical skills Professional asset manager/ Engineer Basic On line Qualitative Yes Basic On line Indicative of asset condition NA NA dependent on test Yes commercially available from selected vendors NA dependent on test Basic technical skills NA dependent on test Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 7-23

Tool or technique Cover meter Service type Waste and potable Assets covered Assessment Material Service interruption Concrete assets - Cover depth to Reinforced On line slabs, beams, walls, reinforcement concrete assets tunnels and dams, etc. Accuracy Commercialized Skills required Accurate survey of reinforcements in concrete assets Yes widely available Basic Non-pipeline assets Civil and Building Assets Crack measurement Electrical potential (half cell) Holiday detector Impact echo method LPR for corrosion monitoring Magnetic flux leakage Waste and potable Waste and potable Waste and potable Waste and potable Waste and potable Waste and potable Concrete assets - slabs, beams, walls, tunnels and dams, etc. All reinforced concrete assets Coated assets Concrete assets - slabs, beams, walls, tunnels, dams, etc. Concrete assets - slabs, beams, walls, tunnels, dams, etc. Metal assets tanks, etc. Measuring linear deformations, cracks, settlements and shrinkage coefficients Detection of corrosion Location of defects in asset coatings Determine concrete thickness or location of internal defects Concrete temperature that allows structure s long-term performance to be determined Reinforced concrete assets Reinforced concrete Ferrous and concrete assets with coating for corrosion protection On line Quantitative Yes widely available On line Up to 95% Yes widely available Off line if internal coating is to be tested Qualitative Concrete On line Good accuracy for thickness measurements Reinforced concrete On line Results are indicative only Metal loss Iron and steel Off line Quantitative assessment Yes widely available Yes- available from commercial suppliers Yes commercially available from selected vendors Yes - specialist consultants Basic Basic Basic technical skills Basic skills for operation; categorization of defects requires expertise Basic Specialist skills 7-24

Non-pipeline assets Civil and Building Assets Tool or technique Measurement of strain Phenolphthalein indicator (carbonation testing) Pull-off adhesion testing Schmidt hammer Ultrasonic measurements - discrete Service type Waste and potable Waste and potable Waste and potable Waste and potable Waste and potable Assets covered Assessment Material Service interruption Any component made Measurement of No specific On line Accurate Yes of homogenous strain requirements commercially material, dams available Any cementituous civil assets Coated tanks, etc. Any cementituous civil assets Steel civil assets Accuracy Commercialized Skills required Carbonation depth Cementituous On line Qualitative Yes widely available Adhesive strength of applied coatings Compressive strength Level of wall thickness and corrosion pit depth Any coated assets Concrete and brick On line Quantitative Yes widely available On line Quantitative Yes widely available Steel On line Quantitative Yes widely available Engineer trained in operation of tool Basic Basic Basic Trained technician Visual Inspection Volumetric X- ray or radiographic testing Waste and potable Waste and potable Civil assets Welded joints, castings, electronic assets, etc. Qualitative visual assessment; can include grading system (see section 3.3) Non-destructive method used for checking the integrity of metal assets Any On line Qualitative NA Operator training required Metal Off line for laboratory testing Accuracy dependent on operator expertise Yes commercially available from selected vendors Operator requires training for image interpretation Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 7-25

CHAPTER 8.0 CASE STUDY DETAILS Chapter Highlights During the case studies the research team sought input from a range of utilities and industry practitioners across the globe in an effort to: Sense-check the protocols being proposed by the research team. Ground the report in practicalities and provide industry insights. Identify good practice in condition and performance assessments. Provide examples of implementation in different utilities. The following case studies are detailed in this chapter: Case Study 1: Scottish Water s Program of Treatment Plant Assessments Case Study 2: Scottish Water s Approach to Grading of Water Mains Case Study 3: Water Corp s Asset Condition Assessment (ACA) Program Case Study 4: Water Corp s Assessment Approach for Water Tanks Case Study 5: Water Corp s Investigation of a Trunk Main Failure Case Study 6: Water Care s Assessments of Sewerage Assets Case Study 7: Water Care s Assessments of a Critical Sewer Case Study 8: Melbourne Water s Assessments of Steel Tanks Case Study 9: Sydney Water s Management of M&E Assets Case Study 10: City of Bellevue s Risk-Based Approaches Case Study 11: Massachusetts Water Resources Authority RCM Program Case Study 12: MWRA s Strategies for Pipe Network Management Case Study 13: CSIRO s Assessment of a Cast Iron Transmission Main Case Study 14: CSIRO s Assessment of an AC Force Main Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-1

8.1 Introduction An important objective of this research was to draw upon the experience of a wide range of water industry professionals and utilities, and thereby reflect the current state of the art in condition assessment practices across the sector. Various aspects of the research program were designed to facilitate this. For example, a web-based survey was used to gain baseline information on the U.S. sector. The list of tools identified as having relevance to the water sector was also distributed to industry practitioners, along with the reviews of individual tools. Comments received were subsequently integrated into the research outputs. A major portion of the industry interaction was carried out in Phase 2 of the project. During this phase, various utilities were approached and asked to provide information on case studies for inclusion in this report. Case studies were subsequently undertaken with a sample of utilities across Australia, New Zealand, the United States and the United Kingdom. Information on each case study was collated using a questionnaire and interview based approach, written up in a standard format, and sent to each case study partner for review. This chapter briefly outlines the purpose of the case studies and the utilities that contributed information. The full texts of the case studies are then presented. Insets relating to the case studies are distributed throughout the report in appropriate sections and referenced to the case studies below. 8.2 Purpose of the Case Studies During the case studies, the research team sought input from a range of utilities and industry practitioners across the globe in an effort to: Review and comment on the protocols being proposed by the research team. Provide industry insights and practical experience. Identify good practice in condition and performance assessments. Provide examples of implementation in different utilities. Case study partners providing a significant contribution to the project were: Scottish Water, Scotland, United Kingdom Water Corporation, Perth, Australia Water Care, Auckland, New Zealand Melbourne Water, Melbourne, Australia Sydney Water, Sydney, Australia City of Bellevue, Washington, United States Water Resources Authority, Massachusetts, United States Two asset-specific case studies have also been included that draw upon the research team s previous research and consultancy experience. These case studies illustrate the complexity of analysis that can be required to interpret the results of inspection data. 8-2

8.3 Case Study 1: Scottish Water s Program of Treatment Plant Assessments Case Study Summary Key issues covered in this case study include: The response of a water utility to the consolidation of three utilities into one large service provider. The role of condition assessment in regulatory reporting. The use of condition and performance grading to categorize the state of assets within treatment works. The use of representative sampling and modeling to give a strategic assessment of the overall asset stock. See case study insets 2-4, 2-7, 3-11, 3-16 and 4-1. 8.3.1 Utility Details Scottish Water was established in April 2002 from a merger of the three previous water authorities (West of Scotland Water, East of Scotland Water and North of Scotland Water). Its main functions are to provide clean water to 2.2 million households and 133,000 non-domestic, mainly business, properties in Scotland and to treat their wastewater. It is funded largely from charges to customers and from borrowing approved by the Scottish ministers. Scottish Water is the fourth-largest water services provider in the United Kingdom and one of the 20 largest businesses in Scotland. It has an annual turnover approaching 1 billion, and it is estimated that its capital assets are worth 28.2 billion at full replacement cost (Auditor General, 2005). 8.3.2 Case Study Focus In 2004, Scottish Water undertook a systematic condition assessment of assets within critical water and wastewater treatment works. This effort was combined with an overall data improvement program undertaken in parallel to the development of corporate data systems, which was necessitated by the merger of three authorities into one service provider for the whole of Scotland - Scottish Water. At the same time, Scottish Water assessed the condition of a representative sample of water and wastewater treatment works (randomly sampled), to provide a profile of asset value against condition and performance grade, which was used as an input to the regulatory reporting process. 8.3.3 Assets Considered in the Program For this case study, the assessment program of interest focused on treatment works. 8.3.4 Key Drivers The assessment program was driven by the regulatory reporting and the capital investment planning cycle. Given the consolidation of the three legacy systems into one corporate system, an additional driver for undertaking the assessments was to supplement legacy data of varied and Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-3

uncertain quality with new consistent data of known quality, so that strategic assessments could be made with more confidence. The program in question was therefore undertaken to provide assessments of asset condition and performance grade profiles across Scotland based on newly collected (rather than legacy) data. Scottish Water is/was required to report on the condition and performance of its asset stock each year. In contrast, England and Wales were required to report similar information every five years. The program of condition assessment was thus partly driven by the desire of Scottish Water to understand better the use of condition and performance data in regulatory reporting in England and Wales. 8.3.5 Key Program Features Since the program was driven by regulatory reporting needs and was strongly influenced by the (one-off) circumstance of bringing together three legacy systems into one, the assessment program had to be undertaken. As such, it was designed more on the basis of affordability and cost minimization, rather than justified through an explicit cost-benefit analysis. 8.3.5.1 Grading and Assessment of Assets A system of condition and performance grading was used in the program similar to those described in Section 3.3.3; the reader is referred to this section for detailed information on this approach to condition and performance assessment. As noted in Section 3.3.3, with this approach, condition and performance grades are allocated to assets through visual assessment, performance review, and with reference to standard grade definitions. The grade definitions used by Scottish Water arose from a system stipulated by U.K. industry regulators (Ofwat in England and Wales and the Water Industry Commissioner (WIC) in Scotland). Grading systems are/were used to give an assessment of asset condition/performance and thus the grade profile across the asset stock (the proportion of asset value in each grade band). There was also a fully developed set of guidelines on how to subdivide complex assets into a consistent asset hierarchy. The grading systems allocated a condition and performance grade to units (assets) within treatment works. A unit was defined as the smallest type of asset recorded separately on the asset inventory; a unit was considerably larger than items commonly found in maintenance management systems. For example, a complete pump set was recorded as one unit rather than being broken down into its components - the pumps, motors, control gear, delivery pipework and valves, and so forth. An assessment of fitness for purpose (asset capability) was also made (this allowed the impact of upstream assets to be considered; a unit may be fit for purpose but still be graded as performing badly because of an upstream asset). The operational status of units was also collected along with other asset-related data. 8.3.5.2 Stratified Sampling of Assets In guidance for regulatory reporting, WIC stated that there was no formal requirement for Scottish Water to survey its entire asset stock. Instead, the authority could survey sufficient assets to give a representative view. A representative sampling strategy and statistical modeling of data was identified as an appropriate means of meeting the objectives of the study; this meant a sample of treatment works could be surveyed and used to estimate the state of the whole asset stock. The approach involved the design of a stratified sampling scheme that focused on important assets, but also sampled the rest of the asset stock. Data was collected for the sample 8-4

during site surveys. Visual assessment was used to grade assets using data collection protocols developed by external consultants drawing on grading systems previously used within the legacy authorities. 8.3.5.3 Analysis of Sample Data The sample of grades and associated data were analyzed in a statistical package. Generalized linear modeling was used to produce models that described the probability of an asset being within a given condition/performance grade. The factors considered in the modeling exercise were: Works type (water treatment or wastewater treatment) Treatment type Geographical area (former East, North or West of Scotland) Unit class Asset life category A risk grade (good, fair or poor) As noted, the resulting models expressed the probability that an asset would be in one of the condition grades, and were of the form: Probability (Grade) = ax +by + cz where: a, b and c are coefficients derived from the analysis and X, Y and Z were the covariates used (works type, treatment type, etc.). 8.3.5.4 Extrapolation across the Asset Stock In combination with data on the overall asset stock and the value of different assets (in modern equivalent terms), these models allowed the grade profile for the asset stock to be calculated; the expected value of assets in each grade band was estimated for all of Scottish Water s treatment works. As shown in Figure 8-1, this profile was then used to compare the state of Scottish Water s asset stock to that of companies in England and Wales. However, the project also concluded that interpretability of such plots is limited due to significant differences in the underlying data and grading procedures. Figure 8-1. Comparison of Assets in Condition Grade 4/5 by Asset Value. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-5

8.3.6 Key Lessons and Tips for Success 8.3.6.1 Commitment to Data Improvement Given the starting position of disparate data sources spread across three legacy data systems, a key strength was the commitment by Scottish Water to improve data on assets and asset condition/performance to allow analysis to be undertaken for strategic planning and other purposes. 8.3.6.2 Cost Saving While a representative sampling approach was used in the assessment program, an attempt was also made to substitute works that were being assessed as part of the capital investment planning process when this had no effect on the representative nature or the sample (the impact of substitution was determined by an expert in statistics). Cost saving was realized because some works were assessed to meet two drivers: 1) to provide information on capital investment requirements and 2) to provide the profiles of asset condition and performance to be used in regulatory reporting. Cost savings were also realized by clustering assessment tasks to minimize travel time and to increase the efficiency of the assessment program. Substitutions were again used in this process, for example, where randomly selected sites were very remote, substitution for similar but more accessible works was allowed. 8.3.6.3 Consistency of Grading Grading is a subjective process and effort needs to be expended to ensure consistency. To facilitate this, Scottish Water therefore provided leveling training to all assessors and also audited the grading process across a number of teams. In general, consistency of application was good, although some issues were noted with respect to the consistency of subdivision of assets into a consistent hierarchy (e.g., what was considered a unit differed between assessors). 8.3.6.4 Focus on Grades of Concern Generalized linear modeling of allocated condition and performance grades was used to extrapolate the survey results across the asset stock. However, after undertaking initial analysis, it was noted that there was an issue with the confidence limits of the statistical modeling of the grade profiles. This meant that while a 1 to 5 grade system was used in the assessment of assets, there were insufficient assets of grade 4 and 5 to model in a statistically significant sense. As such, these grades were combined. Furthermore, it was noted that there was no interest in the distinction between whether or not an asset was in condition grade 1 or 2, so these grades were also combined. The final models thus gave the probability that assets would fall into grade bands 1 and 2, 3, and 4 and 5. 8.3.6.5 Confidence Grades It is desirable to allocate a confidence grade against the condition and performance grade to indicate the information upon which the grade was allocated (for example, full visual inspection, opinion of operator, inferred, etc.), and thus the relative confidence in the grading. 8-6

8.4 Case Study 2: Scottish Water s Approach to Grading of Water Mains Case Study Summary Key issues covered in this case study include: The development and use of sophisticated decision support IT systems for management of water infrastructure assets. The use of opportunistic and planned sampling in development of models. Stepwise justification and development of decision support systems. Extrapolation of condition/performance across the asset stock and the use of surrogate data to fill gaps in necessary data sets. See case study insets 2-4, 3-5 and 4-1. 8.4.1 Utility Details See Case Study 1 for details. 8.4.2 Case Study Focus Within Scottish Water, condition and performance assessments for water mains are undertaken using a combination of 1) failure data and 2) predictive models generated from pipe samples. These are incorporated into a GIS-based system that facilitates the prediction of the condition and performance of the entire water distribution network through extrapolation of data and predictive models. 8.4.3 Assets Considered in the Program For this case study, the assessment program of interest focused on water mains. The approach discussed is broadly equivalent to Scottish Water s treatment of sewers, although the assessment procedure for individual assets is based on CCTV inspection, rather than cutout sampling. 8.4.4 Key Drivers In Scotland, grades need to be allocated to water mains to provide information for regulatory reporting, expressed in terms of the percentage of asset value in different condition and performance grades. In previous planning cycles, grades were also used to give an indication of investment needs; condition and performance grades were used in a matrix to identify areas for further investigation. More sophisticated approaches are now being developed and applied that are in line with service-driven, risk-based asset management approaches. 8.4.5 Key Program Features 8.4.5.1 Development of INMS Scottish Water has implemented a system called Integrated Network Management System (INMS), which was initially developed in-house by the former Authority, East of Scotland Water. INMS is a comprehensive GIS-based tool used for understanding the performance of water distribution systems. INMS provides an assessment of the condition and performance of distribution mains, the level of risk associated with each pipe and the predicted degree of tuberculation. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-7

8.4.5.2 Use of Pipe Sampling INMS uses a range of information collected through the operation of the network and via pipe sampling. As discussed further below, both planned and opportunistic sampling has been used to provide the data from which the models of pipe condition and performance were developed. All samples were physically cut out and analyzed; none were assessed using nondestructive testing (NDT). The INMS models were developed in a stepwise manner. Initial sources of data were available in the form of previously collected and stored pipe samples and photographs. These data were re-inspected and the resulting data analyzed to allow relationships between the pipe characteristics and pipe condition to be generated. For example, corrosion rates of the buried ferrous mains were calculated using information on pit depth and age. Tuberculation growth rates for different materials were calculated using tuberculation height measurements, pipe diameter and material. The initial pipe samples had, however, been taken in known problem areas and/or taken opportunistically from exposed sections of burst or leaking water main at the time of excavation for repair. Opportunistic samples were also taken during other maintenance work, such as the installation of valves and meters or as part of a rehabilitation program. Opportunistic sampling is, by definition, unplanned, though selective use of samples may be undertaken to reduce bias (for example, exclusion of samples from any analysis that would obviously skew the data set). When compared to random samples taken in structured programs, the use of opportunistic data can skew the predictive capacity (leading to pessimistic predictions). To aid the development of INMS, and to improve the models, pipe samples were also taken in structured programs (essentially a gap filling exercise to supplement the opportunistic sampling). Random samples were taken in a representative manner; samples being identified according to combinations of pipe characteristics (material, diameter, age, etc) and factors relating to the pipe environment (soil type, conveyed water type, etc). Three pipe samples were taken from each combination. Overall, the models have been built up from 7,000 pipe samples, with the sampling being focused on problem pipe materials (less sampling of plastics pipe). In an average year, a further 200 samples are now taken and used to refine deterioration curves. These samples are taken as part of rehabilitation schemes and also to investigate areas adjacent to known problem areas (to determine if the problems are likely to propagate). The samples taken are also used to improve the model of condition grade. This approach provides data that is not entirely representative, but is less skewed than opportunistic sampling during failure events (burst repairs) or in the problem areas themselves. 8.4.5.3 Grading Procedures within INMS The condition grading procedures used in INMS assign a condition grade of 1 to 5. Two distinct approaches are used to grade the condition of pipes 1) burst history and 2) a predictive condition grade model. The performance grading procedure used in INMS uses a rules-based approach to band assets. The base data (pipeline attributes) on water mains, held on the GIS, are analyzed to assign performance grades. Performance grades can be allocated according to three separate approaches: 8-8

A pipe-sample based predictive model (grades relate to predicted deposits and degree of tuberculation). Corporate data (grading based on historical complaints and water quality failures). Cost grading (grading based on operational costs). The data sources used within the condition and performance grading procedures are thus related to structural condition information, characteristics of the pipeline, internal and external environment and the performance of the system. Similarly, the models relate explanatory variables to the observed condition/performance grade. For pipe condition, explanatory variables include pipe characteristics (diameter, material, lining, wall thickness), age, soil type, material and corrosion rate. 8.4.5.4 Extrapolation across the Asset Stock To apply the models of condition and performance grades across the asset stock, the attributes (variables) used in the models must be available for all assets. Where there are data gaps, various surrogate data are used to allow these gaps to be filled. For example, the use of material installation dates and housing age to estimate unknown pipe ages. If no surrogate data exists, such that there is still a data gap, default data (assumed values) are used. However, the use of default data can have a significant impact on the degree of certainty associated with the predictions. 8.4.6 Key Lessons and Tips for Success 8.4.6.1 Managing Costs Costs were minimized by the use of data collected from opportunistic samples. A stepwise development of models was also adopted that involved collection of data, analysis, integration into predictive models, review and subsequent improvements. 8.4.6.2 Number of Samples The spatial extent of the sampling was dictated by affordability issues; predictive capacity of models would improve with more samples, but the number of samples used in the production of the models was in line with statistical requirements. The frequency of sampling in time is not meaningful in this application; the models describe mathematically the way a pipe deteriorates from new to very poor condition based on the observed relationship between model determinants and condition. 8.4.6.3 Stepwise Development Development of INMS was undertaken as discrete projects subject to a formal approval process in which the additional expenditure had to be justified to management. This approach made the development costs affordable and ensured that a business case was made for each stage. 8.4.6.4 Corrosion Rates Corrosion rates for ferrous pipes were calculated from the recorded internal pit depths measured on the samples. Linear corrosion rates were initially assumed (known to be simplistic); non-linear corrosion rates are now assumed. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-9

8.5 Case Study 3: Water Corporation s ACA Program Case Study Summary Key issues covered in this case study include: The implementation of a comprehensive condition assessment program using corporate systems as a repository of information collected and collated. A systematic process for the condition assessment of assets undertaken for multiple purposes. The use of a common assessment framework across the majority of asset types. See case study inset 3-18. 8.5.1 Utility Details Water Corporation provides water and wastewater services to thousands of households, businesses and farms in towns and communities spread over 2.5 million square kilometers. Water Corporation also maintains drainage and irrigation services for both residential and commercial properties. 8.5.2 Case Study Focus Water Corporation has undertaken a rolling program of condition assessment of all infrastructure assets, excluding water distribution and sewer network assets, under a program termed ACA. ACA involves a fit for purpose assessment, which takes into account condition, performance, the availability of spares, etc. 8.5.3 Assets Considered in the Program There are 86,000 assessable elements covering most the asset types. These include water and sewer pipes (larger transmission pipes only), valves, pumps, motors, tanks and reservoirs, including the roof, storage structure, appurtenances and buildings. Once fully implemented, it is anticipated that the program will require approximately 6,000 assessments to be undertaken each year. 8.5.4 Key Drivers The key driver for implementing ACA was to achieve a better understanding of asset condition and to provide a sound basis for good asset management. This included the need to develop a better understanding of remaining asset life and the potential asset renewal costs in the medium to long term. ACA also provides a structured process for the routine inspection of assets that would not otherwise have been undertaken. 8.5.5 Key Program Features 8.5.5.1 Overview of ACA ACA had the over-riding objective to develop a corporate register of asset condition to be used for various purposes, including maintenance planning, renewals planning, management reporting and financial reporting (end of asset life). As such, the ACA program provides: 8-10

A register of asset condition. Information for replacement and refurbishment programs. Information for maintenance planning. Information for asset depreciation. Corporate reporting of condition. 8.5.5.2 The ACA Process The ACA process provides a consistent assessment of asset condition across a range of asset types. Information collected and collated during assessments is stored on a custom-built add on to an existing corporate management system. The ACA database provides a common framework for the storage of condition-related data, including the interventions (maintenance tasks, refurbishment, etc.) deemed necessary to address asset deterioration. The ACA database can be interrogated in various ways, for example, to allow management reports to be generated and programs of assessments to be compiled for a given period. The ACA process is shown in Figure 8-2. Figure 8-2. Schematic of Water Corporation s ACA Process. Figure 8-2 shows that there are two routes through the assessment process. The first is the formal ACA process, where condition assessments are made routinely at a time informed by findings of any previous assessment. The second is an asset deficiency process that runs in parallel to ACA. Through this second process, assessments and/or interventions can be undertaken in response to any deficiencies in assets reported by routine operation/maintenance. The main ACA process involves collecting information on the asset to determine if it is fit for purpose. Any required interventions are identified and programmed in for action. Assessment records are updated and the date and requirements of the next assessment specified. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-11

8.5.5.3 Grading of Assets In the ACA process, information about the asset, which may include data collected during an inspection, performance history, compliance with regulations, availability of spares and criticality is used to generate two ratings for the asset. These are on a scale 1 to 5 (1 being excellent and 5 being very poor condition). The first rating is current condition, which takes into account inspection results and other relevant information about the asset performance. The second rating is required condition. This is dependent on the importance of the asset, but can never be 1 or 5 (an asset can not be required to be in either new or in derelict condition). The difference between the current and required condition grades is the gap rating, for example, if the required rating is 3 and the assessed condition is 5 then the gap rating will be -2. Where a negative gap rating is generated, it is a requirement that an intervention is proposed to bring the asset up to the required condition. This may be a capital solution such as replacement or an operational intervention such as an overhaul or minor refurbishment. There is also the option to recommend increased monitoring or undertake a more extensive inspection. The financial year that the intervention needs to be implemented and the estimated cost are also required. An assessment of remaining asset life is also made (in three bands: life remaining less than five years, five to 10 years and more than 10 years). Where the asset is assessed to have less than 10 years of remaining life, the assessor must assign an intervention if one has not already been assigned as a response to a negative rating. 8.5.5.4 Data Sources and Inspection Techniques Since the ACA program covers a wide range of assets, various techniques are used to provide data on asset condition. Depending on the asset in question, these may include visual and camera inspection and occasionally inspection techniques such as pressure testing, direct current voltage gradient (DCVG), incotest (eddy current), phenol, ultrasonics and magnetic flux leakage monitoring. For mechanical and electrical assets, the assessment is usually based on the availability of spares, support, performance and obsolescence. Pump efficiency and condition monitoring are carried out, but this is often to optimize maintenance timing and efficiency rather than as part of the ACA process. For important (critical) and/or high-risk assets, in depth techniques can be required. In such cases, the assessment techniques are selected and assets inspected by a specialized team of personal. Water Corporation has a centre of expertise (the Mechanical and Electrical Services Branch) that provides technical support to the rest of the organization, including determining the most appropriate inspection technique (see Case Study 4). 8.5.6 Key Lessons and Tips for Success 8.5.6.1 Size of the Assessment Program The size of the assessment program has resulted in a significant workload for staff members and resources have been stretched, especially in clearing the initial backlog. The development of future assessment programs will have an increased focus on asset criticality to ensure the prioritization of assessments is effective. However, the commitment to assess all assets has driven data improvement across the asset stock. 8-12

8.5.6.2 Need for Auditing and Quality Control Ensuring consistency of assessments is difficult as the utility s activities are spread across a large area. Effort needs to be expended in the form of quality control, training and auditing to ensure this consistency is achieved. 8.5.6.3 Use of Confidence Grades The ACA system requires confidence grades to be allocated that characterize the data source upon which the assessment has been made. This is considered good practice. 8.6 Case Study 4: Water Corporation s Assessment Approach for Water Tanks Case Study Summary Key issues covered in this case study include: An iterative approach to the inspection and assessment of complex assets like tanks, based on the ACA process given in the previous case study. The use of a range of tools and techniques to support condition assessment undertaken for asset-specific and general asset management purposes. See case study inset 6-3. 8.6.1 Utility Details See Case Study 3 for details. 8.6.2 Case Study Focus This case study focuses on the approaches used by Water Corporation to assess the condition of water tanks as part of the ACA program (see Case Study 3). 8.6.3 Assets Considered in the Program Water Corporation manages water tanks of various design including ground level and elevated steel plate and steel panel tanks and concrete structures with steel reinforcement. 8.6.4 Key Drivers Assessments of water tanks are undertaken within Water Corporation primarily to determine whether the tank is, and will remain for the foreseeable future, safe and functional and to identify maintenance or renewal requirements. A specific issue of corrosion control has also been identified on some tanks, for example, tanks with steel floors have a known failure mode in that the steel floor can corrode from below. 8.6.5 Key Assessment Features 8.6.5.1 The Standard ACA Inspection Procedure Inspection of tanks by Water Corporation is undertaken periodically under its ACA program (see Case Study 3). Often this is aligned with maintenance activities and the internal inspection is sometimes carried out by divers who also clean the tank; the divers give the asset manager a report of the internal condition and defects, which can be accompanied by video footage. Inspection of the other elements of the tank, such as roof and external condition, are reported by Water Corporation personnel. Similarly, when emptied for cleaning, operators undertake visual inspection. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-13

The tank site is broken down into assessable elements for the purposes of condition assessment. These assessable elements usually comprise the water retaining structure, the roof, the pipes/valves, the ladders/landing and where applicable, the tank stand and the membrane liner. Each of these elements has their own condition assessment. Inspection templates are used to guide the inspector to all the components of the tank that should be examined, for example, walls and floor, stand, roof, and to facilitate the capture of information about the appearance of the asset. An example of the guidance provided for the walls and floor is shown in Table 8-1. Table 8-1. Guidance for the Grading of Condition. Walls and floor reinforced concrete/steel plate/panel A New or near new walls/floor with few minor defects and meeting all functional requirements. B C Walls/floor remain in excellent condition requiring little attention; all functional requirements are met. Steel: some external coating defects with surface corrosion to exposed areas some internal coating defects but steel is cathodically protected. Reinforced concrete: some cracking but sealed/calcified and no evidence of active rebar corrosion. Remains functional; optimal life is not threatened; little remedial action is required at this time. D E Steel: external coating breaking down, significant pitting corrosion to exposed areas some internal coating defects with some corrosion of exposed areas (steel not cathodically protected). Reinforced concrete: cracks/joints weeping but no rebar corrosion; some minor spalling but little metal loss to rebar. Remains safe/functional but optimal life at risk; increased monitoring or remedial action required. Steel: general breakdown of coating; areas of severe pitting corrosion. Reinforced concrete: cracks/joints leaking (water running); severe spalling of concrete; severe rebar metal loss. Safety/functionality of tank at risk; optimal life being severely impacted; early remedial action. When an asset falls into category D or E, it is required that the inspector provide adequate comments to support the observations. For category E assets, photographs and/or a report is required. 8.6.5.2 More Detailed Assessments More detailed or technical assessments are normally undertaken based on some perceived need: 1) visual inspections reveal some issues (defects) that warrant further investigation, 2) issues with assets of a similar type have been identified or 3) it is known that visual inspection will be insufficient to identify defects, for example, under floor corrosion. The asset manager and specialist engineers within Water Corporation s Mechanical and Electrical Services Branch discuss the context of the asset and determine the scope of the assessment. A range of non-destructive techniques can be used in these assessments, including: Magnetic flux leakage floor scanners to scan floor plates. Ultrasonic sensors (to evaluate floor scanner results and to test walls and areas of floor not accessible to the floor scanner). Concrete cover meter. 8-14

8.6.6 Key Lessons and Tips for Success 8.6.6.1 Support Material for Condition Assessments Checklists are a useful aid to the assessment of complex assets. Taking a photographic record of defects or issues of note provides valuable information. 8.7 Case Study 5: Water Corporation s Investigation of a Trunk Main Failure Case Study Summary Key issues covered in this case study include: An investigation into a trunk main s (large diameter water transmission pipe) condition driven by a significant failure event with an unusual failure cause and failure mode. The impact of other infrastructure assets on asset risk. The use of screening tools and analysis to understand areas of potential risk and to target more detailed investigations. The use of indirect inspection techniques (DCVG survey) and other data to identify sites for pipe excavation and detailed on-pipe inspection. The use of condition assessment to inform risk management strategies. The application of experience gained through a specific study to other assets to leverage value from inspection data. See case study inset 2-8. 8.7.1 Utility Details See Case Study 3 for details. 8.7.2 Case Study Focus The investigations considered were driven by a catastrophic failure of a trunk main (large diameter water transmission pipe) in a metropolitan area. This resulted in extensive flooding, damage to property and severe disruption to traffic on a freeway. The case study focuses on the subsequent assessments of condition and risk undertaken in response to this failure. 8.7.3 Assets Considered in the Program The failed asset was a 1065 mm diameter steel transmission pipe constructed in 1959; nominally 9.5 mm thick with a 19mm cement mortar lining. Its operating pressure was approximately 16 bar. 8.7.4 Key Drivers The key driver for the program was the catastrophic failure of a transmission pipe through an unexpected failure mode leading to severe traffic disruption and other impacts. Given that catastrophic failure of steel is unusual, Water Corporation needed to determine if the circumstances associated with the failure were an isolated case or if there were similar risks along the pipe (and other similar assets) that needed to be managed. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-15

8.7.5 Key Program Features 8.7.5.1 Condition Assessment Approach Water Corporation s trunk mains are mostly wrapped steel pipes with cement mortar lining. The trunk main network has a significant level of flexibility, such that a significant number of trunk mains can be taken off-line without affecting service provision. As such, Water Corporation has implemented a routine CCTV inspection program whereby trunk mains are inspected when the pipes are taken out of service for maintenance purposes. This allows inspection of the integrity of the lining (e.g., the presence of any significant cracking or delamination can be determined). In addition, the cement mortar may become stained where there is corrosion of the steel. This can also be identified during the CCTV inspection, which allows additional investigations to be undertaken if necessary. The inspections are undertaken using a proprietary system called Challenger. In addition to CCTV functionality, Challenger has recently been developed to include the ability to conduct metal thickness testing at selected locations. 8.7.5.2 Details of the Asset Failure While significant effort is expended to understand the condition of the trunk mains using these inspection techniques, a trunk main failure still occurred that led to severe disruption. The failure mode was due to external scouring of the trunk main by water flowing in two drainage assets that intersected the trunk main in a drainage pit. Scouring by the drainage water led to external erosion and corrosion of the trunk main over a significant area. The CCTV inspection program did not pick up the deterioration of the asset since there was little internal corrosion to stain the lining. Furthermore, and common for steel mains, the failure mode was catastrophic. The more usual failure mode for steel pipes is pinhole corrosion, which leads only to small leaks. Catastrophic failure is related to general loss of metal due to corrosion/erosion over large areas and is a rare occurrence when normal levels of asset protection and maintenance are applied. 8.7.5.3 Forensic Investigations Given the unusual circumstances of the failure and failure mode, Water Corporation instigated a detailed condition assessment of the trunk main in conjunction with an assessment of risk to determine if the particulars of the failure represented an isolated case. The investigation was undertaken to: Identify any sections of pipe where a similar failure mode could occur (other locations where drainage infrastructure intersected the trunk main). To investigate the condition of the asset in sections where similar levels of failure consequence could be incurred. The investigations were designed to improve knowledge of the likelihood of further failure so that the risk of the main failing could be better managed. An extensive study including coating integrity (DCVG) investigations, metal thickness testing (ultrasonic), internal camera inspections and visual inspection of the main at selected locations was carried out over a period of several months. The timeline of the program is summarized as follows: May June July Burst occurred. Direct Current Voltage Gradient survey. Critical infrastructure audit. 8-16

July July/Aug Sept Dec Oct Oct Nov Dec Dec Internal CCTV inspection. Inspection of drainage infrastructure. Excavations and metal thickness testing at defect locations. Final report on cause of failure event in May. Contingency plan for future burst event. Arborist report on trees located near main. Design report for installation of cathodic protection. Findings and recommendations reported. 8.7.5.4 Identification of At-Risk Sites Eight sections along the main were identified where there could be similar damage associated with drainage assets. The trunk main and surrounding infrastructure was excavated at these points and the condition of the main and coating assessed. At all locations, full assessment of damage was difficult due to the close proximity of third party infrastructure. At three locations, there was no obvious indication of damage having occurred. At three locations, corrosion of the trunk main was evident and detailed investigations were carried out; coating damage, corrosion, gouging of the main and buried infrastructure in direct contact with the trunk main were noted. Two further locations were also investigated but no drainage was found and the main was in good condition. 8.7.5.5 Survey and Inspections As indicated, a DCVG survey was also undertaken along the trunk main. The survey identified a total of 183 coating defects, considered a very high number, particularly with regard to the relatively short (2800 meters) length of pipe inspected. Of these 183 defects, 40 were deemed to be medium or significant in terms of the soil voltage gradient present. To gain a better understanding of the severity of defects located by DCVG, it was decided to excavate a number of the identified coating defect sites. These sites were chosen to reflect locations with an increased likelihood of significant corrosion. The main survey parameters indicating increased probability of significant corrosion were considered to be: Low soil resistivity (<5000 ohm-cm). Pipe soil potentials more positive than -500mV. Large (significant) soil voltage gradient indications at coating defect sites. Crossings or proximity to buried third party structures. Presence of groundwater. Likelihood of sulfate reducing bacteria and related corrosion inducing bacterial activity. The secondary survey parameters indicating increased probability of significant corrosion were considered to be: Specific grouping or spacing of coating defects sites at pipe field joints or third party damage. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-17

Trees and associated regrowth along the pipe route. Evidence of marine sediment in pipe right of way. Representative sites were selected for excavation that had a minimum of two of the main and one of the secondary indicators given above. As a result, the pipe was exposed and coating defect investigations carried out at 24 sites. At each site, the condition of the coating and pipe was investigated and any remedial work necessary carried out before reinstatement. The characteristics of the defects were also related to the findings of the DCVG survey. The information gained from the investigation can be applied in the management of other trunk mains. The observed defects were used to calibrate the results from the DCVG to improve the interpretability of subsequent surveys on other trunk mains. It was concluded that while the internal condition of the main was good, there were a large number of external defects present. Most external damage existed where third party infrastructure (especially drainage) impinged on the main and included damage to the coating, gouge marks, chain marks and pitting. Wall thickness was reduced to around 6 mm over a few small areas and 3 mm in localized areas of pitting (c.f. original wall thickness of 9.5 mm). Structural analysis indicated that the trunk main would fail at 287 meters(m) head, which was still significantly above the operating pressure of 160m head and design pressure of 210m head (based on design pressure of fittings). 8.7.5.6 Outcomes of the Investigation As a result of this inspection and survey work, a number of recommendations were made. These included options for the long and medium term management of the trunk main, as well as for management of large diameter mains. Risk reduction strategies for the section of main that failed ranged from the relocation of the entire length to the replacement of fittings. These options were assessed using a corporate risk matrix and risk assessment process. The preferred option included the installation of cathodic protection, remediation of any interference from or to adjacent infrastructure, replacement of fittings and the monitoring of leakage. 8.7.6 Key Lessons and Tips for Success 8.7.6.1 Use of Risk Analysis to Focus Investigations Risk along a trunk main should be characterized and used to focus investigations, preferably before a failure occurs where this is deemed justified. The risk analysis should consider all risk factors in a systematic way as well as unusual failure modes. 8.7.6.2 Leveraging Value from Investigations Value was derived from the extensive program of investigations presented in this case study because it: Provided insight into the residual risk associated with the asset. Ensured that replacement of the asset could be deferred with no increase in risk exposure. Allowed results to be applied in the management of other assets. 8-18

8.7.6.3 Third Party Interference Third party interference is a significant source of risk for pipeline assets. In particular, where other infrastructure have been buried in close proximity to a trunk main, it is very likely that damage to the coating and/or pipe has occurred. 8.7.6.4 Use of a Common Datum When using in-pipe techniques in conjunction with on-pipe techniques, it is important to have a common datum (the point measurements are taken from and referenced to) to allow matching of internal and external observations. 8.8 Case Study 6: Water Care Services Limited Assessments of Sewerage Assets Case Study Summary Key issues covered in this case study include: Condition assessment of a trunk sewer network using various inspection techniques. The use of existing operational knowledge to prioritize assessments. The use of a risk-based approach to contextualize the results of inspection. The use of the results of a condition assessment program to specify on-going inspection and monitoring activities. See case study insets 3-3 and 3-15. 8.8.1 Utility Details Water Care Services Limited (Water Care) is New Zealand s largest company within the water and wastewater industry. The company supplies bulk water to Auckland through a regional water network. An average of 347,000 M 3 of water is supplied daily. The water is drawn from 12 sources comprising of 10 dams, the Waikato River and an aquifer at Onehunga. The company also operates a regional wastewater network and treats 288,000 M 3 of wastewater a day at the Mangere Wastewater Treatment Plant. 8.8.2 Case Study Focus In 1999, Water Care identified that the condition of Auckland s trunk sewer assets were unknown and that, in some cases, the consequences of failure would be significant. Project Condition Assessment and Risk Determination (CARD) was implemented as a result; CARD for wastewater mains (2000 to 2003) was complimented by ECARD an assessment of wastewater pump stations electrical systems, undertaken in 2001-2003. 8.8.3 Assets Considered in the Program The condition assessment of large diameter sewerage assets; Water Care operates approximately 300km of trunk sewers (>300DN) of various materials. 8.8.4 Key Drivers The main drivers for project CARD were to understand condition, risk and economic life of assets in more detail and to provide a feed into the asset management strategies for wastewater assets. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-19

8.8.5 Key Program Features 8.8.5.1 Project Goals Through various risk assessment processes and workshops with staff, Water Care identified that the condition of the sewer mains was unknown and that in some cases the consequences of failure would be significant. Project CARD was implemented as a result of this work. The stated project goals of CARD included: Develop an asset condition monitoring and performance assessment strategy, including data management, storage and analysis. Determine the condition of the identified high-risk pipelines and potential failure modes. Identify and quantify the risks of failure and economic life of the high-risk pipelines. Identify management and mitigation measures, including: Maintenance and repair activities. Rehabilitation needs. Replacement needs. Develop programs for ongoing monitoring and assessment of the high-risk pipelines. 8.8.5.2 Identification of Inspection Technologies The inspection technologies used in the program were researched through the World Wide web, discussions with other utilities, reference to technologies available locally (in New Zealand) and research trips to the United Kingdom and Canada (mainly to establish the capabilities of sonar survey equipment and the management of overflows). The techniques eventually selected for use in the program included: CCTV of wastewater mains. Sonar for siphons. Walk through for larger diameter mains and larger duplicate siphon pipes. Visual assessment of defects was augmented through video, still photos and cover meter measurements. Concrete cores were also taken for laboratory testing. Some sections of sewers had dimensions checked using laser technology. Manholes were inspected during CCTV sewer inspections or on an ad-hoc basis if opened for other purposes. 8.8.5.3 Program Implementation and Outcomes Risk analysis was undertaken at the beginning of the CARD project to identify priorities for inspection using available operational knowledge. The project was managed as a normal engineering project; both CCTV and sonar surveys were undertaken by external contractors. Sonar contracts were awarded by competitive quotations, CCTV by identifying best level of service (i.e., contractor equipment/capability) available. It was initially thought that the budget would not allow all pipes to be inspected, but by 2005, nearly all pipes had been surveyed. Over the period 2000-2005 Water Care undertook a complete inspection of the entire 300km trunk network, mainly using CCTV and visual inspection (approximate cost AU$1.5 million). The condition data, together with previous history and criticality assessment, was analyzed using Weibull analysis to look for correlations between age, criticality, observed 8-20

condition and fault history. Correlation was poor, and a more detailed analysis using factors such as pipe material, soil condition, pipe bedding, construction standard and so forth is thus being developed. The assessments provided a ranking of critical mains for further monitoring, rehabilitation or renewal. As well as undertaking necessary maintenance and replacement work, Water Care s on-going strategy is to monitor sewers with the poorest internal condition rating (condition rating grade 5), representing approx 5% of the total network, which includes monitoring of key brick and concrete sewers. Monitoring is undertaken using CCTV or, in some limited cases, visual inspection. Where condition dictates, patch lining is undertaken. If the structural condition of the sewer is compromised, full structural lining is installed. Where structural lining is not practical, the sewer is either renewed or is relayed on a new alignment (often using directional drilling). 8.8.6 Key Lessons and Tips for Success: 8.8.6.1 Use of Local Knowledge An assumption at the start of project CARD was that Water Care and local consultants did not have the requisite knowledge to put together the program. Water Care professionals now consider that it is important not to underestimate the value of in-house and local knowledge, nor overestimate the state of the art in other countries. 8.8.6.2 Capturing Available Operational Knowledge Capturing available operational knowledge was a key aspect of the prioritization of the assessment program. While no formal assessments had been undertaken, operational staff had a reasonable feel for those assets that were in poor condition. 8.8.6.3 Leveling Assessments Problems can occur in a large program of condition assessment because some assessments can be more conservative than other assessments, depending upon who performs the assessment. Water Care now attempts to overcome this by having the same team do the analysis and reporting. 8.9 Case Study 7: Water Care s Assessments of A Critical Sewer Case Study Summary Key issues covered in this case study include: A detailed investigation of a critical concrete sewer in poor condition and subject to significant H 2 S related corrosion. The limitation of using defects alone as a means of characterizing condition and risk of failure. The iterative use of more detailed studies to understand asset risk, support decision making and defer capital programs. The use of structural analysis to understand the probability of asset failure under a range of loading scenarios. The collection of auxiliary data to refine the analysis. See case study inset 3-3. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-21

8.9.1 Utility Details See Case Study 6 for details. 8.9.2 Case Study Focus A detailed investigation into the risk and condition of an interceptor sewer crossing an environmentally sensitive area with potential for significant aesthetic and environmental impacts should the asset fail catastrophically. 8.9.3 Assets Considered in the Program An 18 kilometers (km) long reinforced concrete interceptor sewer, cast in situ in sections of 30 feet (10m), and built between 1960 and 1965. The shape and size of the pipeline varies along its length, as does the earth fill above the pipe. The sections of the pipeline of specific interest to the case study are 85 inches semi-elliptical. 8.9.4 Key Drivers Initial inspection of the asset was undertaken under a program to determine the overall condition of all sewerage assets (see Case Study 6). Preliminary structural analysis was then required to assess the risk of collapse in sections subjected to significant levels of acid attack. Collapse of these sections would lead to significant health, environmental and third party consequences. The implication of this analysis was that there was a risk of collapse under certain conditions and on-going deterioration would increase the likelihood of failure. Additional analysis was undertaken to understand better the rate of deterioration and the risk. In part, the additional analysis was driven by the fact that there was insufficient redundancy in the network to allow the asset to be replaced. 8.9.5 Key Program Features 8.9.5.1 Results of Initial Condition Assessments The condition assessment of the sewer was initially undertaken using walk through inspection techniques. Data was collected in terms of observed defects, supplemented through photographs and notes. The distance along the asset was measured by wheeling above the waterline. The assessment indicated that the interceptor sewer was in poor condition; about 5.5 km having been subject to significant acid attack, penetrating more than 30mm. A relatively short section of the sewer (171m) was found to be in very poor condition; 80mm (+/-10mm) having being lost from the original (as-built) wall thickness of 180mm. This section was between two siphons (thus having limited air exchange) with a large connection discharging into it, these factors providing conditions for the generation and release of H 2 S. The concrete in the section had corroded to the extent that the inner of two sets of reinforcement bars (cast within the pipe wall) were exposed in places. In addition, there was relatively little earth cover above the section, a situation that can lead to a higher live load being imposed on the sewer. 8.9.5.2 Implications of Structural Analysis Initial structural analysis was undertaken to consider the impact of existing soil and groundwater loads as well as traffic on the deteriorated asset. The sewer structure was analyzed as a two-dimensional plane frame with the sewer modeled as a series of beam elements with nodes at 150 to 300mm centers and support from the soil being considered as elastic springs at 8-22

the node points. The top one-third of the pipeline was modeled with reduced wall thickness to represent the impact of acid attack. Various loading scenarios were analyzed and the calculated safety factors compared to the requirements of applicable codes. The results of these assessments implied that there was a risk of structural failure under certain conditions, but that more information was required to refine the analysis. Subsequent investigations into the amount of earth cover, water table depth, concrete thickness, concrete strength and soil parameters were undertaken to refine the assumptions made in the analysis. The conclusions from the refined analysis were that the sewer could safely sustain existing soil, ground water and expected traffic loads. However, the remaining wall thickness was still uncertain and results indicated that the sewer would be over stressed under certain traffic loading conditions. Significant on-going deterioration of the asset was expected to occur and increase the probability of failure over time. 8.9.5.3 Risk Mitigation and Additional Investigations As a result of the assessment, it was determined that immediate remedial action was required using a sulfate-resistant spray-on lining system. Furthermore, the asset was deemed at risk and early replacement was considered. Such replacement was not practicable given there was insufficient capacity in the network to allow the replacement to be readily undertaken. An expansion of the network was, however, already planned that would provide the spare capacity required to undertake the capital works. Additional investigations were undertaken to understand the risk associated with the asset and to determine if the capital renewal could be deferred until after the additional network capacity was constructed. Mapping of the corrosion was undertaken along the section of asset in poor condition. A cover meter, which induces a magnetic field in the reinforcement bars, was used to measure the depth of cover to the reinforcement bars along the asset. The results of this inspection were used in combination with laser profiling to determine the amount of material lost from the wall and the rate of asset deterioration and thereby predict the change in asset condition over time (in terms of wall thickness). More refined structural analysis was then undertaken using three dimensional (3D) finite element modeling. The modeling showed that the loss of material down to the first reinforcement bar was not as significant as first thought; the pipe would lose structural integrity when there was corrosion down to the outer of the two reinforcement bars, rather than the inner. It was concluded that the level of risk associated with the asset was acceptable and that its renewal could be deferred until after the network capacity was expanded through other capital projects. In summary, the initial condition assessment was undertaken using a screening approach that determined the presence of a significant defect; concrete had corroded to the extent that the inner reinforcement bar of the pipe wall was showing. The presence of the defect was, however, only a relative indicator of condition. Structural analysis was required to determine what the defect meant in terms of asset risk. Inspection of the asset was then undertaken to determine the rate of deterioration and the results of the inspections used in refined modeling studies to put the asset deterioration into context. The cost of the detailed analysis was justified by the need to understand the risk in more detail and by the lack of affordable risk management options. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-23

8.9.6 Key Lessons and Tips for Success 8.9.6.1 Limitations of Defects as a Metric of Condition While condition assessment undertaken through visual assessment is a pragmatic technique in many instances, the presence of structural defects needs to be contextualized to understand risk fully. In this case, an exposed reinforcement bar was interpreted as being indicative of a high risk of failure. Additional detailed analysis indicated the probability (and thus risk) of failure was lower than anticipated. This allowed deferral of a capital project to a time when the network could support the rehabilitation of the interceptor sewer. 8.9.6.2 Justifying Additional Analysis through Better Knowledge The cost of the additional analysis was justified because of the high level of perceived risk and the lack of available options to manage that risk. An iterative approach to assessment can therefore be justified based on risk, in which more accurate (and expensive) techniques are used to refine the knowledge of an asset and give better support to decision making. 8.10 Case Study 8: Melbourne Water s Assessments of Steel Tanks Case Study Summary Key issues covered in this case study include: A comprehensive and planned approach to the inspection and assessment of steel water storage tanks. The historical development of condition assessment and other maintenance practices, from ad hoc approaches used in the early 1990s to the systematic investigations carried out today in line with strategic asset management needs. The identification of an unexpected source of asset deterioration associated with construction of water storage tanks on limestone foundations contaminated with chlorides and the development of an assessment program to manage the associated risk. The use of scoring procedures to facilitate condition grading of complex assets. See case study insets 2-3 and 5-7. 8.10.1 Utility Details Melbourne Water is a supplier of bulk water services in Melbourne, Australia and the surrounding region. Owned by the Victorian Government, Australia, Melbourne Water is responsible for managing water supply, sewerage and drainage assets valued at AU$8.4 billion. Services provided to the community include management of Melbourne's water supply catchments, removal and treatment of most of Melbourne's sewage and management of rivers, creeks and major drainage systems throughout the region. 8.10.2 Case Study Focus The case study considers investigations into the deterioration of steel water storage tanks. The discussion is contextualized in terms of the historical development of assessment practices for steel water storage tanks, from ad hoc assessments undertaken up until the time when Melbourne Water was incorporated in 1994 to the systematic strategies for inspection and 8-24

corrosion management that are now undertaken, which fully align with corporate asset management policies. 8.10.3 Assets Considered in the Program Fully enclosed steel water storage tanks constructed on a limestone foundation according to designs based on standards from the American Petroleum Industry Standard (API 651). 8.10.4 Key Drivers The need to manage assets of significant value in an effective manner and to address risks associated with asset deterioration and corresponding water loss. 8.10.5 Key Program Features Steel water storage tanks started to be constructed in and around Melbourne in the 1960s. During the 1970s and 1980s a relatively large number of steel tanks were constructed to meet increased demand or to replace open basins where water quality standards needed to be improved. In 2005, Melbourne Water operated 38 steel service reservoirs (40 were being operated at the time of writing), with an estimated replacement value of AU$190 million. 8.10.5.1 Development of Approaches to Management of Water Tanks When it was incorporated in the early 1990s, Melbourne Water inherited a fragmented approach to the management of its water tanks. Basic information relating to the construction of the tanks was available in the form of design drawings. However, on-going assessments were undertaken separately by various departments focusing on individual issues such as corrosion, mechanical and electrical components, valves, and so forth. Information recorded during these assessments was in a summary format (for example, asset satisfactory ) and was not collated. As in other water companies, water storage reservoirs represented a significant capital investment and the assets provided played a critical role in the provision of water services and management of risk. Furthermore, there was a developing understanding that ad hoc approaches to management and maintenance were not providing the information necessary for long-term asset stewardship. Melbourne Water started to develop a structured approach to the management of these assets drawing on the knowledge of management practices being applied to large diameter steel pipes. At the time these asset management procedures were being developed, a particular and unexpected failure mode started to become evident - the corrosion of the tank s steel plate floor. 8.10.5.2 A Legacy Design Issue Melbourne Water s steel water storage tanks are constructed from steel plates that are welded in situ. Tank floors are specified as uncoated steel plates, lapped at joints and laid over a base course of 100mm nominal thickness of crushed limestone; the limestone overlays a subbase of crushed basalt rock. The choice of limestone as a base material was primarily for the purpose of providing a protective alkaline barrier to the uncoated floor plate underside. However, limestone also has natural propensity to contain large volumes of chlorides (as salts). This issue was not considered in the original specifications. During the early 1990s a steel service reservoir floor-plate was found to have perforated. During October 1994, substantial water leakage was observed coming from the reservoir, which had to be immediately taken out of service to allow emergency repairs. While the perforation failure was confirmed as being due to corrosion, the mechanism of deterioration was not immediately obvious. At the time of the incident, another service reservoir began to show similar Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-25

signs of corrosion and steps were taken to reduce the corrosion rate by implementing cathodic protection. Subsequent investigations into the asset deterioration confirmed that the limestone was heavily contaminated with calcium chlorides. The impact of this salt on the floor plate underside is typically characterized as pitting corrosion. As a result of these investigations, Melbourne Water began a program of assessment. Twenty-two tanks were confirmed as having high levels of chloride contamination within the limestone base-course material with associated high levels of corrosion. Specifications for new service reservoir construction were revised during the 1990s, to ensure that this problem did not occur in the future. Nevertheless, Melbourne Water still has to monitor for, and treat, corrosion in reservoirs that were built prior to this period. The failure mode associated with this under floor corrosion is not catastrophic, however, significant (order ML/day) leaks can occur. Given the high visibility of water conservation issues in Australia coupled with the proximity of the tanks to residential areas, such leaks can result in significant adverse publicity as well as having the potential for causing property damage and associated community distress. 8.10.5.3 Current Inspection and Management Strategy Given the perceived level of risk, Melbourne Water s steel service reservoirs are now regularly inspected to ensure that the potential for asset failure is appropriately managed. Inspection strategies have been developed in consultation with external consultants and are considered by Melbourne Water to be industry best practice. Comprehensive corrosion assessments are undertaken on a periodic basis ranging from one to five years. Generally speaking, assets that are deemed to pose a significant risk are inspected on a one to two year basis, whereas those that pose a smaller risk are inspected on a three to five year basis. Outage strategies are implemented based on business risk and operational needs with due consideration given to both water quality standards and structural integrity requirements. The inspection can be timed in accordance with cleaning requirements; tanks have to be cleaned every three to eight years, depending on the level of silt build up. Melbourne Water tends to avoid the use of divers to undertake structural assessments. Nevertheless, divers may be used on an ad hoc basis where circumstances limit outage opportunities. When dewatered, the tanks are inspected using a range of techniques. In particular, magnetic flux leakage floor scanners are used to map corrosion of steel floor plates. Other components of the asset are also assessed, typically through visual inspection. Observations are recorded and reported in a standard format that details the observed feature (asset component) and any salient remarks. The conditions of functional components of the asset are also assessed against a standard scoring scheme developed by Melbourne Water. This results in weighted scoring for various asset components, as illustrated in Table 8-2. 8-26

Table 8-2. Weighted Scoring for Asset Components. Category Weighting Score Total Structural stability 6(0-30) 3 18 Light gauge roof adequacy 1(0-2) 1 1 Road and storm water drainage 1(0-3) 0 0 Extraneous fittings 1(0-5) 0 0 Protective coatings adequacy 1(0-2) 1 1 Reservoir security 1(0-2) 1 1 Cathodic protection systems 1(0-3) 2 2 TOTAL 23 The scores are interpreted using the following grading procedure: If the total is 31 or more then the condition is 5. If the total is between 24 and 30 then the condition is 4. If the total is between 14 and 23 then the condition is 3. If the total is between 8 and 13 then the condition is 2. If the total is between 0 and 7 then the condition is 1. In the example given above, the tank was awarded an overall condition grade of 3. Results of assessments are compiled into asset-specific reports that include remarks relating to specific issues identified for action along with recommendations and priorities. The condition of all Melbourne Water s steel tanks are also periodically summarized in a management report, which uses a traffic light system to highlight problem areas (for example, assets with a condition grades 4 and 5 are flagged by red cells). 8.10.6 Key Lessons and Tips for Success 8.10.6.1 Alignment of Condition Assessment and Asset Management Ad hoc assessment strategies spread across a number of departments do not provide the information required to support effective stewardship of complex assets. Instead, asset specific policies and procedures must be developed with appropriate resourcing and lines of responsibility. These asset-specific approaches should be developed in line with the development of corporate risk and asset management policies. Detailed investigations can be required when there is an unexpected failure or deterioration of any asset. The ability to undertake these investigations and implement risk management strategies has been greatly enhanced by the development of asset management approaches. If justification for management strategies is presented in both engineering and financial/economic terms, the process of obtaining the necessary buy-in from senior management is greatly facilitated. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-27

8.11 Case Study 9: Sydney Water s Management of M&E Assets Case Study Summary Key issues covered in this case study include: The use of qualitative and quantitative techniques to assess and monitor the condition of important electrical and mechanical assets. The use of a CMMS in condition and maintenance management. The range of inspection tools used in asset inspection and condition monitoring of important mechanical and electrical assets. See case study insets 3-1, 3-8, 5-1 and 6-1. 8.11.1 Utility Details Sydney Water Corporation (SWC) supplies clean water to more than 1.6 million homes and businesses in the greater Sydney region, New South Wales, Australia. Raw water is treated at nine water filtration plants; the largest plant at Prospect treats more than 80% of the area s water. The water is distributed to customers via a network of 259 service reservoirs, 151 pumping stations and nearly 21,000 km of water mains. SWC also collects and treats more than 1.2 billion liters of wastewater each day. The sewerage network consists of about 23,500 km of sewer pipes in 25 separate sewerage systems with 30 sewage treatment plants (STP). Around 75 per cent of the wastewater is processed at the three largest plants at Malabar, North Head and Bondi. 8.11.2 Case Study Focus The management of important electrical and mechanical assets through the use of a combination of qualitative and quantitative techniques that integrate traditional practical engineering level practices with a more strategic level approach to maintenance management. 8.11.3 Assets Considered in the Program Important above ground electrical and mechanical assets. 8.11.4 Key Drivers SWC developed its condition assessment programs with the prime objective of ensuring that critical assets do not fail. The perspective taken is to focus on assets that are required to run the business; various business risk factors are evaluated to promote the effective management of these important assets (including cost, risk of failure and environmental risk). 8.11.5 Key Program Features SWC has developed an approach to condition assessment and management that incorporates a suite of quantitative and qualitative tools. Quantitative methods include obtaining numerical results from inspection and performance monitoring and use of software and mathematical algorithms to analyze this and other data. Qualitative methods include incorporating experienced staff members intuitive reasoning into the analysis of an asset s condition as well as non-quantitative condition assessment techniques such as visual inspection. 8-28

Prior to adopting this approach (termed Quali-Quanta by SWC), SWC applied high standards and regular planned maintenance with little analysis or optimization. The analysis of asset management information now occurs simultaneously on two levels: Level 1: Higher level analysis based on qualitative and quantitative analysis. Important aspects of this level include planning, analysis of long term behavior of assets and application of experienced staff members intuitive reasoning. An asset s condition is analyzed in terms of a wide range of detailed parameters including, number and nature of past failures, meantime between failures, experienced operators and managers intuition and cross-checks between the failure and running history of related/linked assets. Level 2: A more practical level and is based on engineering analysis. Each asset s condition is categorized by assigning it a grade after site inspection and condition assessment. 8.11.5.1 Sources and Use of Data and Information To facilitate the management of assets, information from a range of sources is collated and analyzed. Much of the data is held on a CMMS. The CMMS documents asset history, scheduling, preventive maintenance, work orders, labor and expense tracking, procurement and reporting associated with assets. Data from the CMMS is supplemented with condition assessment information such as that from maintenance staff. Desktop information is also added to this, including the opinions of a wide range of personnel, such as maintenance supervisors. The collated data is statistically analyzed for each individual asset. Statistical analysis commonly consists of a Bayesian approach and Weibull correlation analysis. SWC has found that Weibull analysis is useful when there is limited failure data available, such as a small sample size. 8.11.5.2 Inspection Tools Used Table 8-3 outlines the main inspection and condition monitoring tools used by SWC for electrical and mechanical assets. Condition monitoring is conducted on selective assets depending on their importance. For example, if a failure would result in significant downtime or a major replacement cost, the asset is regularly condition monitored or inspected. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-29

Large motors, transformers, diesel engine generators, gas engines at Malabar STP. Table 8-3. Inspection Tools and Techniques Used by SWC. Tool Applicable assets Purpose and details Frequency of use Oil testing and Monthly, done through a analysis service provider. Used on all critical and large assets using oil. Used where lubrication of engines is critical. Determines how long oil will last. Infrared thermography Switchboards and motor circuit motor control centers. To take snapshots of hot panels and cables in order to allow hot spots to be pin-pointed. A program that covers all plants ensures testing every six months to a year. On-line condition vibration monitoring Machines with bearings or couplings. Determines whether bearings, footings or couplings have adequate integrity and have not gone soft. Includes a data logger. Once a month or three times monthly, depending on the criticality. Vibration analysis 1000kW raw sewage pumps and centrifuges. Collects data on machines running uninterrupted. For instance, analysis of friction losses on bearings. SWC has in-house vibration analysis. specialists who analyze testing data output such as spectra. Data is extracted into software and a reactive work order is created in the CMMS. This allows SWC to do more of its reactive maintenance in a planned manner. On-line data collected every half an hour. Motor circuit analysis Motors. Used to assess a range of items, including the integrity of the motor circuit operating the motor, the condition of insulation between the winding and the frame of the motor, integrity of the motor starter and to determine if the winding is shortcircuiting. Offline testing, very reliable. Every six months. Level 1 plant condition assessment All critical plant assets. All assets within a facility are visually inspected. Regularly scheduled as part of ongoing preventive maintenance program. x-ray testing Ultrasound Pressure vessels, welded pipe joints, castings. Mostly used on concrete structures such as digester walls and pipelines. Weld testing. Usually only carried out on a one-off basis on assets requiring assessment of structural integrity. Usually only carried out on a one-off basis rather than regularly. Not commonly used. Testing is periodically conducted as part of SWC s regular planned maintenance program. In addition to regular in-house testing, specialist contractors conduct testing of specific assets, such as pressure vessels. Contractors receive certification for a specific interval. When considering adopting a new condition assessment tool or technique, SWC compares the effectiveness of the new tool with the current tool, if being used. The comparison involves a cost-benefit evaluation per asset. Maintenance cost history for each asset is used as the fundamental benchmark. If a new tool costs more, it still may be considered if it gives an earlier warning of failure. 8-30

8.11.6 Key Lessons and Tips for Success 8.11.6.1 Use of Desktop Studies SWC has demonstrated over a number of years that there is a strong correlation between results from site condition assessment and desktop analysis. This has enabled SWC to justify condition assessment programs that have a smaller number of site inspections than previously. Approximately 10% of site inspections are routinely conducted on an ongoing basis to prove that the correlation between the desktop and on-site condition grading is being maintained. 8.12 Case Study 10: City of Bellevue s Risk-Based Approaches Case Study Summary Key issues covered in this case study include: The range of condition assessment programs instigated by a provider of infrastructure management services to manage risk and reduce costs. Coordinating with the transportation department to target inspections and minimize pipe replacement sewer and water main replacement costs. A focus on system performance and reliability of water and wastewater pipes to reduce claims from property damage or business interruptions. The use of risk-based approaches to target inspection effort, including the targeting of water and sewer pipes that could lead to flooding of basements and property damage. See case study insets 2-6, 3-2 and 6-4. 8.12.1 Utility Details The City of Bellevue provides infrastructure management services, including wastewater collection, water distribution and stormwater collection for approximately 130,000 customers. Other utility companies provide water and wastewater treatment services. The water and wastewater systems are each comprised of roughly 500 miles of pipelines. The oldest pipelines in the water and wastewater systems date back to 1948; a large portion of the system (nearly 50%) was installed in the 1960s. 8.12.2 Case Study Focus A range of condition related programs undertaken by an infrastructure management service provider to improve management of the asset stock. 8.12.3 Assets Considered in the Programs Bellevue has undertaken a range of condition related programs to improve the management of the asset stock and to reduce costs. These include a review of asbestos cement (AC) pipe break data and subsequent replacement strategy, CCTV inspection of sewers and a leakage reduction program for water mains. 8.12.4 Key Drivers Bellevue is interested in reducing claims from property damage and business interruptions. This has increased focus on system performance and reliability. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-31

There is also a need to justify the reserves set aside for renewal and replacement of assets and to determine the most appropriate means for targeting asset renewal expenditures. 8.12.5 Key Program Features Bellevue has undertaken a range of condition assessment programs to improve the management of the asset stock, as summarized below. 8.12.5.1 AC Pipe Replacement Program A review of historical water main break data in the 1970s and 1980s determined that 80% of main breaks occurred in AC pipes between four to six inches in diameter. This led to a program of replacing all asbestos cement water pipe in the system. This program is still underway; pipes are replaced when breaks occur and/or when the roadways are resurfaced. 8.12.5.2 Sewer Pipe CCTV Program A comprehensive CCTV program is underway, in which it is planned to CCTV all sewer pipelines over a 10 year period. Given this strategy of inspecting all sewers, initial city efforts focused on the most critical pipelines (with regard to economic, public health or environmental impact). The program started with critical pipelines (20% of the system), then moved through the system with newer pipes getting lowest priority. Pipelines are scored according to the NASSCO system, and those receiving poor condition scores (4 or 5) are evaluated by senior staff to determine need for renewal. Any pipe under a roadway scheduled for resurfacing is scheduled for CCTV as a high priority, this allows pipe replacement to be undertaken in conjunction with the road resurfacing. City staff members have also performed hydraulic and surface water modeling to determine areas of the system and hydraulic conditions that would cause the sewer hydraulic gradeline to be above basement floor levels, and thus where the city may be susceptible to property damage claims. Condition assessment and operations and maintenance activities are then prioritized accordingly. 8.12.5.3 Leakage Reduction Program A risk-based leak detection program has been underway for several years. This initially focused on reducing system water loss, but subsequently focused on avoiding property damage and the associated claims. High-risk pipes were identified by overlaying several property damage-related risk factors, including properties where home elevations are below adjacent street levels, areas where older (pre-1986) ductile iron water mains are installed and areas of high percolation soils (likely to transmit water rather than force it to the surface where the water would be observed). Acoustic leak detection efforts have targeted areas with these three risk factors to prevent minor leaks from becoming major problems. 8.12.6 Key Lessons and Tips for Success 8.12.6.1 Coordination with Transportation Department A critical driver for the pipeline assessment efforts is the schedule for resurfacing of the roadways in the service area. Due to considerable savings for the utility if pipeline replacement projects do not incur repaving costs, much of the sewer CCTV efforts and AC pipe replacement efforts are targeted as a result of the roadway resurfacing schedule. 8-32

8.13 Case Study 11: Massachusetts Water Resources Authority RCM Program Case Study Summary Key issues covered in this case study include: The use of RCM to optimize maintenance practices at a treatment work facility. The range of condition monitoring techniques used in condition monitoring of the assets. The coordination of various initiatives to increase the effectiveness of maintenance practices. See case study insets 2-5, 3-17 and 5-4. 8.13.1 Utility Details The Massachusetts Water Resources Authority (MWRA) provides wholesale drinking water supply, treatment, and distribution and wastewater collection, treatment and disposal services for 61 member communities serving a population of roughly 2.5 million customers in the greater Boston area. The water distribution and wastewater interceptor systems are comprised of roughly 300 and 257 miles of pipeline, respectively. Typical daily water delivery is approximately 225 million gallons per day (mgd). The regional wastewater treatment plant at Deer Island is among the largest in the country with an average daily flow of 350 mgd and a wet weather treatment capacity of 1.2 billion gallons per day. 8.13.2 Case Study Focus A reliability centered maintenance program undertaken at the Deer Island Treatment Plant. 8.13.3 Assets Considered in the Program Wastewater treatment work assets. 8.13.4 Key Drivers MWRA has a general focus on cost-effectiveness and reliability, which served as primary drivers for efforts to minimize asset lifecycle costs and for development of an extensive reliability centered maintenance program at the Deer Island Treatment Plant. 8.13.5 Key Program Features 8.13.5.1 MWRA s RCM Program MWRA has implemented RCM and condition monitoring programs, primarily focused on the Deer Island Treatment Plant (wastewater) facilities. At an early stage in the development of these approaches, MWRA assigned dedicated staff members to lead the development of asset management efforts for the utility. Early efforts included benchmarking other RCM programs inside the water/wastewater industry (Broward County) and outside the industry (Coors Brewing, Dofasco Steel). Nearly 200 plant systems were identified and prioritized based on criticality for formal RCM program development. At the time of writing, RCM programs had been implemented for 55 of these systems. This involved extensive workshop efforts to determine optimum operational, maintenance and condition monitoring strategies. As noted in earlier chapters, RCM Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-33

workshops determine frequency and type of maintenance for individual equipment, often recommending condition-monitoring tasks. MWRA considers that the implementation of a formal RCM program has been very effective in enhancing the reliability and performance and reducing life cycle costs of its large facility equipment. 8.13.5.2 Other Related Initiatives Over US$140 million in equipment is currently monitored via a proactive condition monitoring program. Condition monitoring programs for the major equipment use a range of techniques, including oil analysis, temperature analysis, acoustic ultrasonic and vibration analysis. For larger equipment (value of roughly US$400,000 or greater), permanent vibration and temperature monitoring equipment has been installed for enhanced trend analysis. Staff members are also trained in specialized maintenance (e.g., laser alignment) techniques for equipment rebuilds to improve equipment reliability. 8.13.5.3 Benefits Associated with Initiatives Specific benefits of these initiatives include: Demonstrated reduction in over 20,000 maintenance work hours per year as a result of all reliability programs including RCM, condition monitoring, preventive maintenance optimization and productivity improvements, resulting in labor savings of over US$700,000 annually. Proactive oil sampling program resulted in avoided (scheduled) oil changes valued at roughly US$50,000 per year. Substantial (non-quantifiable) avoided and deferred costs due to enhanced equipment reliability and performance, extended equipment life, avoided permit violations, etc. Qualitative staff improvements in terms of teamwork, communications and commitment to success. 8.13.6 Key Lessons and Tips for Success A program champion is key, whether for the overall asset management and condition assessment effort, or for the individual condition assessment programs. Implementation of the formal RCM program has been a very effective way for MWRA to enhance the reliability and performance, and reduce life cycle costs of their large facility equipment; Proactive maintenance programs for critical equipment have focused on oil, temperature, acoustic ultrasonic, and vibration analysis. Investments in staff training, sophisticated mechanical alignment equipment, and permanent monitors on certain major equipment have yielded savings in asset life cycle costs and performance reliability. 8-34

8.14 Case Study 12: MWRA s Strategies for Pipe Network Management Case Study Summary Key issues covered in this case study include: The use of different condition-based approaches used for management of pipeline assets. The use of condition-related data to drive operational and capital interventions. See case study insets 2-5, 3-9 and 3-17. 8.14.1 Utility Details See Case Study 11 for details. 8.14.2 Case Study Focus MWRA use a range of condition-based approaches to facilitate the management of their network assets. In particular, water and wastewater strategic planning is undertaken using a riskbased approach that utilizes both asset condition and consequence of failure to prioritize future asset renewal needs. Water system condition assessment is based primarily on analysis of leak data, while wastewater system condition data is based on comprehensive CCTV data. 8.14.3 Assets Considered in the Program Water and wastewater pipeline assets. 8.14.4 Key Drivers MWRA has a general focus on cost-effectiveness and reliability, which serve as primary drivers for efforts to minimize asset lifecycle costs in the management of pipeline assets. Water loss and safe yield issues are primary drivers for an extensive leak detection program. 8.14.5 Key Program Features For the pipeline assets, CCTV inspection (wastewater) and leak detection and valve exercising (water) programs have been the basis for condition assessment and renewal planning programs. Highlights of these programs are described below: 8.14.5.1 Water Main Leak Detection Program Three work crews (8 people) are assigned full time to water system leak detection, using a combination of hand-held portable equipment (leak correlators), and continuous monitoring acoustic equipment. The equipment is used on all MWRA water mains, which are constructed of various materials including steel, cast iron, ductile iron, prestressed concrete cylinder pipe, and reinforced concrete (MWRA has no plastic pipe installed). The work crews have the goal to survey the entire system (300 miles) each year, and survey each of the steel mains twice a year. One crew works only at night to minimize interferences of traffic and other city noise. Magnetic permaloggers are attached to pipes overnight, allowing data to be uploaded remotely. The equipment can then be rotated to a different location the next day or week, as appropriate. 8.14.5.2 Water Main Renewal Forecasting MWRA staff have attempted to use historical leak and failure data to forecast water system renewal needs. Statistical analyses has been performed based on correlating failures to Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-35

several factors including age, material, size, c-value, literature-based expected life, and local factors such as known material defects, salt storage and saltmarsh locations. Once condition scores were established, pipe redundancy (e.g. loop systems to serve customers) was considered in renewal prioritization scoring. Since MWRA are a wholesale provider, all retail systems (customers) were considered equally critical, and no consequence of failure analysis was used. Results of statistical analyses were used in water system master plan forecast of renewal needs and costs. 8.14.5.3 Wastewater Interceptor Inspection and Renewal Planning Program MWRA has performed closed-circuit television (CCTV) inspection of its entire gravity sewer interceptor system, and used these data to assign condition scores to each pipeline segment. MWRA recently shifted to the NASSCO standard 1-5 rating (grading) system, but much of their historical condition data are still in a legacy A, B, C condition rating system. As part of master planning efforts, the pipe sections were prioritized using a scoring approach to analyze the probability and consequence of failure. The probability-side prioritization considered physical pipe characteristics such as age material, pipe condition rating, etc. The consequence of failure analysis utilized GIS to determine what land area would be negatively impacted in the event of a failure. This analysis also considered the hydraulic vulnerability of a pipeline (based on capability to divert/bypass flow if failure occurs). 8.14.5.4 Benefits Associated with Initiatives Specific benefits of these initiatives include: Experience has shown that equipment works well to identify and pinpoint location of leaks, triggering staff to prepare a repair work order. MWRA have quantified substantial reductions in system leaks in recent years; reported system leaks were reduced from 92 per year to 10 per year over an 8-year period. Systematic programs of condition assessment both improved asset/network performance and provided the data required for undertaking strategic planning. 8.14.6 Key Lessons and Tips for Success As with MWRA s RCM program, it is considered that a program champion is key, whether for the overall asset management and condition assessment effort, or for the individual condition assessment programs; MWRA maintains a suite of Key Performance Indicators (KPIs) that drive program efforts; performance against the KPIs is published quarterly to the Board of Directors. 8-36

8.15 Case Study 13: CSIRO s Assessment of a Cast Iron Transmission Main Case Study Summary Key issues covered in this case study include: The standard approach to inspection of a large diameter main using grit blasting (removal of corrosion products using a high-pressure stream of grit and water) and measurement of residual wall thickness. The use of physical failure models to assess the remaining life of the asset. See case study insets 3-4 and 3-6. 8.15.1 Case Study Focus The condition assessment of a 250 mm diameter cast iron water main. The main was installed in the 1860s and remained unlined until 1980 when it was cement lined in-situ. 8.15.2 Assets Considered in the Program Large diameter transmission mains constructed from cast iron. 8.15.3 Key Drivers Five pipe failures had occurred along the main, with two failures also reported in tapping bands. 8.15.4 Key Program Features 8.15.4.1 Asset Details Figure 8-3 shows a typical failure for the main. The photograph shows a section of the pipe wall was removed with two longitudinal splits. This indicates combined corrosion and fracture failure, a failure mode that was also observed in other failed sections exhumed from the main. Figure 8-3. Typical Failure Mode for Cast Iron Pipe. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-37

8.15.4.2 Sampling and Inspection of Pipe Five sections of pipe, each approximately one meter long, were exhumed by the water utility and assessed. Each section was grit blasted to remove graphitized corrosion product and expose the remaining metallic material. A grid pattern of 150 mm x 150 mm was then scribed on the outer surface of each exhumed section. Exhumed sections were then cut to allow access with calipers and the minimum remaining wall thickness in each 150 mm x 150 mm grid square measured. Values ranged from a maximum remaining wall thickness of 13.9 mm to minimum values of 0 mm (indicating through wall corrosion). The scatter in residual wall thickness data illustrates that corrosion damage is inherently uncertain and varies not only between samples, but also across the surface of each sample. 8.15.4.3 Assessment of Condition As outlined in the literature (Davis et al. 2004), raw data from residual wall thickness measurement can be used to forecast failure rates in buried cast iron mains following four steps: 1) Converting measured residual wall thickness data to corrosion rate. 2) Quantifying variations in corrosion rate as a probability density function (PDF). 3) Defining a physical failure model for buried cast iron pipe. 4) Combining the corrosion rate PDF with the physical failure model for buried pipes in a Monte Carlo Simulation of long pipelines. In this example, a survivor function (S(x)) for the measured corrosion data was calculated and used in a Weibull plot, as shown in Figure 8-4 (a survivor function is the probability that a variable x, in this case the maximum corrosion rate max corr rate, is greater to or equal to a given value; see Davis et al. 2004 for more details). Since the plot was linear, it indicated that a Weibull PDF could be used to quantify the variation in corrosion rate. This PDF was then used in conjunction with a physical failure model to assess the propensity for asset failure. The failure model considered both the resistance of a CI pipe as it corrodes and the applied service loads (including internal pressure, soil dead loads and surface loads). Figure 8-4. Weibull Plot for Corrosion Data. 8-38

The outputs of the modeling study were summarized in terms of a plot that shows the expected pipeline failure rate as the pipe ages, as illustrated in Figure 8-5. Figure 8-5. Expected Failure Rate per Year. 8.15.5 Key Lessons and Tips for Success 8.15.5.1 Technical Issues of Note Corrosion rates vary both between pipe samples and across the surface of individual samples. Measurement of residual wall thickness does not in itself provide a useable metric of asset deterioration; the results must be contextualized in terms of the asset age and the original dimensions. 8.15.5.2Use of Economic Factors to Determine Remaining Life The use of pipeline failure models allows the probability of failure to be constrained. In conjunction with an evaluation of consequential impacts along the pipeline, the model can be extended to give a quantified assessment of risk and thereby allow an investigation of economic life to be undertaken. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-39

8.16 Case Study 14: CSIRO s Assessment of an Asbestos Cement Force Main Case Study Summary Key issues covered in this case study include: A novel approach to assessment of an AC main using coring techniques and tensile strength testing to assess asset deterioration. The use of physical failure models to assess the remaining life of the asset. See case study insets 3-4 and 3-7. 8.16.1 Case Study Focus The assessment of a 300 mm AC pressure sewer pipe, constructed in 1978. 8.16.2 Assets Considered Large diameter pressure sewer mains constructed from AC. 8.16.3 Key Drivers Five failures had occurred in the AC section, the first in 1986 and the last in 2004. Due to the critical performance requirement of the pipeline in an environmentally sensitive area, there was a need to assess the condition of the AC pipeline and assess the risk of failure. 8.16.4 Key Program Features 8.16.4.1 Soil and Asset Sampling Soil testing was carried out at seven locations along the route of the pipeline to determine the soil aggressiveness (ph, soil characteristics). With this data, a preliminary analysis was carried out to identify sections with high probability of failure (hot spots). Several of those positions were recommended for core sampling of the AC pipe. Following the sampling, data was available in terms of soil type boundaries, soil loads, soil sampling positions, core-sampling positions and the internal pressure extrapolated from hydraulic analysis of the pumping main information. 8.16.4.2 Determining the Level of Deterioration To assess the residual tensile strength of the pipe wall, each core sample was tested according to AS 1012 (1972, Part 10, Method for Determination of Indirect Tensile Strength of Concrete Cylinders). As shown in Figure 8-6, core samples were compressed (crosshead movement of 50 mm per minute) by a uniformly distributed load applied along their length while constrained at their ends. In combination with data on the age of the asset and original tensile strength of the AC pipe, these measurements were used to give an assessment of asset deterioration. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-40

Figure 8-6. Determining Residual Strength of the Cores. 8.16.4.3 Condition Assessment As with the previous case study, the raw data from measurement of asset deterioration can be used to forecast failure rates following four steps: 1) Converting measured tensile strengths to deterioration rates. 2) Quantifying variations in deterioration as a PDF. 3) Defining a physical failure model for buried AC pipe. 4) Combining the deterioration rate PDF with the physical failure model for buried pipes in a Monte Carlo Simulation of long pipelines. In this case, a Weibull probability density derived from the Weibull plot shown in Figure 8-7 was used to quantify the variation in deterioration rate for two distinct soil environments. This PDF was then used in conjunction with a physical failure model to assess the propensity for asset failure. The model considered both the resistance of an AC pipe as it ages and the applied service loads (including internal pressure, soil dead loads, and surface loads). Figure 8-7. Weibull Plot for Deterioration Rates. The outputs of the modeling study were summarized in terms of a plot that shows the expected time to first failure for various loading conditions, as illustrated in Figure 8-8. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-41

Figure 8-8. Distribution of Remaining Lives. The results of the investigation were also summarized for the entire pipeline, as illustrated in Figure 8-9. Expected failure time (years) 4 0 3 5 + 1 std dev Degradation rate unknow n Soil environment 52.010-01 Soil environment 52.010-02 3 0 2 5 2 0 1 5 0 50 0-1 std dev 100 0 Figure 8-9. Life Time Distribution Along the Pipeline. 150 0 Chainage (meters) 8.16.5 Key Lessons and Tips for Success 8.16.5.1 Technical Issues of Note Degradation in cement-based pipelines is strongly influenced by the surrounding soil environment and variations in relevant soil properties cause variation in pipe degradation. For example, variations in soil ph and sulfate content can influence the degree of cement leaching and consequent reduction in pipe wall strength (Dorn et al., 1996) Measurement of residual tensile strength does not in itself provide a useable metric of asset deterioration; the results must be contextualized in terms of the asset age and the original tensile strength. Where the original tensile strength is not known, it is reasonable to adopt a measure based on the original pipe specification given in national standards. 8-42

8.16.5.2 Use of Economic Factors to Determine Remaining Life The use of pipeline failure models allow the probability of failure to be constrained. In conjunction with an evaluation of consequential impacts along the pipeline, the model can be extended to give a quantified assessment of risk and thereby allow an investigation of economic life to be undertaken. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets 8-43

Appendix A UTILITY OBJECTIVES AND RELATED KPIS The following tables show a range of utility objectives that are linked in some way to the condition and performance of various asset types. KPIs that are used to measure performance against utility requirements are also listed. Where there is a shortfall in a measured KPI, some form of assessment will be required. A brief description of the assessment procedure is also presented. Table A-1. Objectives Related to Wastewater Assets. Strategic objective KPIs Outline of assessment approach Invest in alleviation of flooding from sewers Flooding events (freq./vol) Flooding due to asset/equipment failures Surcharging in sewers Improve sewerage infrastructure to prevent collapses Reduce infiltration and inflow Improve sewerage infrastructure to reduce break/choke risk Reduce/remove unacceptable intermittent discharges (UID) Improve performance of sewage treatment works Improve performance of sludge disposal assets Address community expectations regarding odor complaints Number of collapses Measures of infiltration Measures of inflow Number of chokes, bursts, leaks UIDs at CSOs UIDs at pumping stations Pumping station blockages UIDs from sanitary sewers UIDs from combined sewers Consent failures Pollution incidents Equipment failures Biochemical oxygen demand in relation to requirements Suspended solids in relation to requirements Nutrient removal Odor complaints Consent failures Measures of sludge consistency biosolids reuse Number of complaints Use KPIs to identify problem zones, ideally considering all other service drivers to ensure an integrated approach and eventual identification of solutions that give best value for money. Focus in on those assets where there is a regulatory driver or the biggest scope for adding-value. Select additional information required, including CCTV etc. and undertake analysis within each hot spot area. In general involves a complex assessment of hydraulic, environmental and structural condition assessments/modeling. Review the works level performance of sewage treatment works; identify shortfalls in relation to consents, standards and customer complaints/expectations. Prioritize surveys in terms of importance. Review the works level performance and of sludge quality/quantity, identify problem areas and cause. In order of serious (number of complaints), review assets in area, identify problem and cause. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets A-1

Table A-2. Objectives Related to Drinking Water Assets. Strategic objective KPI Outline of assessment approach Improve water quality Water quality compliance at works Turbidity at treatment plants Water quality compliance at tap Coliform compliance (works, service reservoirs) Iron pick up in system Invest in measures to reduce discolored water complaints Improve drinking taste and odor Improve drinking hardness Improve pressure of water supply to customers at risk of low pressure Reduce bursts Reduce interruptions to supply Reduce leakage; achieve and maintain a sustainable economic level of leakage Number of complaints Bursts per unit length Unplanned interruptions Interruption duration Interruption frequency Water pumping station performance (Mean Time Between Failure) Bursts per unit length Infrastructure Leakage Index Leakage Table A-3. Objectives Related to Asset Stock. Identify problem zones through analysis of complaints and sample data. Undertake a program of assessments to determine the root cause (works capacity, pipe condition, etc.). Preferable to combine with other service problems to ensure an integrated approach is taken and eventually, interventions identified that give the best value for money. Identify problem zones/cohorts through analysis of event and sample data. Undertake a program of assessments to determine the root cause Again, preferable to combine analysis with other service problems so as to ensure an integrated approach is taken and, eventually, interventions identified that give the biggest bang for the buck. Identify problem zones through district meter area analysis or similar. Analyze pipe populations to make an assessment of the problem and undertake assessments, active leakage control or pressure management as appropriate. Strategic objective KPI Outline of assessment approach Maintain asset stock at a given level of condition Condition and performance and performance (maintain backlog) grade profiles Improve asset stock condition and performance (reduce backlog) Condition and performance grade profiles Determine sample scheme based on risk, capacity, environmental, financial and other factors. Determine condition/performance profile through sampling. Assess expected life within asset cohorts; this allows a measure of the replacement required to maintain or improve the asset stock condition profile to be made. A-2

Appendix B INDIVIDUAL DRIVERS FOR ASSESSMENT The following tables list a range of individual drivers that can necessitate a utility to undertake a program of condition and performance assessment, independently of any KPI management approach. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets B-1

Table B-1. Drivers in which Condition and Performance Assessment Play a Major Role. Category Focus Driver Asset type Assessment Assess/determine Any asset type. remaining asset lives Develop deterioration curves Condition assessment to provide data for analysis of asset lives and thus timing of required spend, could be done spatially or temporally. Remaining life estimates can also be undertaken as a risk-screening approach; with refined assessments being specified for assets with a 'moderate' remaining life (assets with little life remaining will need replacing in any case, assets with significant remaining lives can be removed from further consideration). Any asset type, but more likely to be pipes. Determine level of deterioration in relation to expected asset life (defined in terms of risk). Characterize level of deterioration. Assess renewals budgets and timing of spend Condition and performance assessment to provide data for use in budget setting and/or justification of capital deferment. Any asset type. Assessment of budget requirements in relation to asset lives and/or deterioration. Smooth renewals spend and/or reduce spend Condition and performance assessment to provide data for use in refining budgets; identifying optimal interventions based on affordability. Any asset type. Optimization of budgets in terms of affordability. Asset Management Prioritize capital programs Condition and performance assessment to target priorities for renewal spend. Any asset type. Assessment of budget requirements in relation to asset lives and/or deterioration. Determine appropriate intervention Condition assessment to determine the level of renovation required and specify rehabilitation approach; selection of least whole lifecycle cost approach (partial replacement, lining, etc.). Any asset type, but more likely to be pipes. Determine structural condition in relation to the needs of available interventions. Improve service delivery Assessment of condition to understand level of service issues (including firefighting capacity), could involve sampling in areas where service problems occur. Any asset type. Hot spots and causes of service failures. Improve system reliability Assessment of condition/performance to understand non-service related shortfalls; e.g., high cost of maintenance to prevent outages. Any asset type. Hot spots and causes of asset failures. Determine asset stock condition/performance Prevent the collapse of asset stock Collection of condition and performance data for asset management. Any asset type. Condition and performance grades. Assessment to determine the condition of key assets. Any asset type. Assets in derelict state. B-2

Category Focus Driver Asset type Assessment Demonstrating asset Condition and performance assessment to demonstrate the overall condition All assets. Determine profile of asset stewardship and/or value of the asset stock (condition/performance profiles by asset value). condition and performance grades. Regulatory/Financial Reporting Comply with CMOM regulations Financial reporting (GASB 34 modified approach) Due diligence Assessment of condition to understand the value of the asset stock and financial risk exposure. Sewerage only. All assets. Any asset type. Determine profile of asset condition and performance grades. Determine profile of asset condition and performance grades. Overall assessment of asset condition and performance. Identify high risk assets Condition assessment to understand risk, given knowledge of failure consequences. Any asset type. Determine condition as a proxy for probability of failure. Risk Management Identify/prioritize risk management interventions Estimate probability of failure/ predicting failure Condition assessment to identify priorities for risk mitigation. Any asset type. Condition assessment to quantify/constrain risk. Any asset type. Assessment of budget requirements in relation to asset lives and/or deterioration. Forensic investigations Condition assessment to understand failure and support litigation. Any asset type. Understand causative factors. Understand causes of failures (similar to forensic) Targeted condition assessment in an attempt to understand asset failures. Could involve sampling of assets in similar environmental and/or operating context to determine if at risk. Any asset type. Understand causative factors relating to asset failures. Operations Risk-informed inspection programs Increase reliability Determine current condition and consider interval for next inspection based on assessment of risk and current condition. Again, similar in focus to the RCM/MO driver, but no need for formalized approach. Attempting to find poor condition/performing assets or components and replace them to improve reliability and reduce direct/indirect costs. Above ground assets, could be used for some important pipes. Above ground assets. Condition as an indicator of risk and thus time until next inspection. Reasons for failure, hot spots, remaining life assessments. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets B-3

Table B-2. Drivers in which Condition and Performance Assessment Play a Minor Role. Category Focus Driver Asset type Assessment Refine RCM/MO Assess condition/performance of components with preventive maintenance and determine if there is scope to modify the maintenance regime; additional preventive maintenance could result in better condition/performance; less maintenance could result in cost savings, if condition/performance where not to deteriorate. Above ground assets. Level of proactive maintenance given reliability-type issues. Operations Reduce O&M costs Essentially the same as RCM/MO refinement, but does not necessarily rely on these formalized approaches being in place. Focus in on reducing direct cost of O&M activities, including identification of problem assets to reduce call outs, pumping costs, etc. Above ground assets. Ideally identification of problem assets, but could be a general assessment of maintenance and operational practices in light of costs. Comprehensive data collection/capture program Collect data for asset management purposes, including an assessment of condition/performance -- likely to be in terms of grades. Any asset type. Condition and performance grades. Asset Management Asset capability assessments Improve the management of asset life cycle Collect data and opinion on whether or not assets are currently fit for purpose; ideally this would be a performance assessment carried out independently of condition, but could involve assessing if condition was affecting fitness for purpose (capability). Assessment of condition and performance to understand the impact of maintenance strategies on asset life. Above ground assets. Any asset type. Performance grade and or simple flag of whether fit for purpose. Asset condition in relation to asset management practices. B-4

Appendix C CONDITION AND PERFORMANCE ASSESSMENT CRITERIA Table C-1 provides some asset observations that relate to the condition of various categories of asset. Note: (V): visual; an auditor would be able to evaluate the assessment criteria directly (visually), (O): opinion based; the auditor would be able to evaluate the assessment criteria indirectly (by interview), (M): measurable; the assessment criteria could be directly measured (inspected/monitored) or assessed through analysis of available operations/maintenance data. Asset Type Buildings Civil assets Electrical assets Table C-1. Condition Assessment Criteria. Assessment criteria Security (V/O) Weatherproof/leaks (V/O) Damp/rising damp (V/O) Level and urgency of maintenance required (O) Rust staining (V) Cracking of brick work or masonry (V) Pointing condition (V) Broken slipped roof tiles (V) State of woodwork; sound to rotten (V) Structural integrity (V/M) Serviceability; useable or not? (V/O/M) Safety of building; considered unsafe? (V/O) Soundness of structure (V/O) Level of wear and tear (V) Corrosion (V/M) Level and urgency of maintenance required (O) Presence of cracking/spalling (V) Presence of staining (V) Leakage (V/O) Deformation of structure (V/M) Safety of structure; considered unsafe? (V/O) Contamination of potable water (O/M) Electrically safe (O/M) Level and urgency of maintenance required (O) Visible wear and tear (V) Condition of insulation (V/M) Break downs and failure history (M) Maintenance costs (M) Health and safety issues (V/O) Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets C-1

Asset Type Mechanical assets Sewers Water mains Assessment criteria Serviceability (V/O/M) Soundness of unit; as new? (V) Level and urgency of maintenance required (O) Level of wear and tear (V) Condition of protective coatings (V/M) Corrosion (V/M) Break down and failure history (M) Maintenance costs (M) Serviceability (V/O/M) Health and safety issues (V/O) Cracking (V) Fractures (V) Deformation (V/M) Loss of fabric; including mortar loss, brick displacement, etc. (V) Joint/connection defects (V) Loss of level (V/M) Smoothness of bore/tuberculation (V) Level of corrosion (V/M) Soundness of lining (V/M) Operational history; bursts, etc. (M) Levels of service (V/O/M) Operating costs (M) Presence of deposits (M) Design regarding current standards (O) C-2

Table C-2 provides some asset observations that relate to the performance of various categories of asset. Note: (V): visual; an auditor would be able to evaluate the assessment criteria directly (visually). (O): opinion based; the auditor would be able to evaluate the assessment criteria indirectly (by interview). (M): measurable; the assessment criteria could be directly measured (inspected/monitored) or assessed through analysis of available operations/maintenance data. Asset Type Buildings Operational security Control and monitoring equipment General performance grades Sewers Water mains Table C-2. Performance Assessment Criteria. Assessment criteria Adequacy for current and foreseeable use; size, location, facilities; current/anticipated shortcomings (O) On-site standby capacity (V/O) Mobile standby capacity and availability (V/O) Number of grid supplies (V/O) Level of manning (V/O) Level of monitoring and control (V/O) Level of telemetry (V/O) Fail-safe systems (V/O) Operational response capacity (V/O) Risk (or history) of consent/quality failure (M) Risk (or history) of service failure (M) Capacity to meet current and future requirements; current/anticipated shortcomings; needs to consider hardware and software (O) Hydraulic adequacy at all flows (O/M) Process capacity at all flows (O/M) Process stability; ability to control (O) Headroom with respect to inefficiencies in upstream/downstream processes (O/M) Distribution between and within assets (V/O) Level of mixing (V/O) Process retention times (O/M) Adequacy for current and foreseeable use (O) Service measures (M) Service measures (M) Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets C-3

Asset Type Raw water storage Raw water intakes Ground water source Pre-treatment Chemical dosing plant Dissolved air flotation Sludge blanket clarifiers Water filtration Assessment criteria Flexibility of draw-off arrangements (O) Susceptibility to eutrophication (O/M) Effectiveness of circulation/de-stratification (O) Effectiveness of scour valves (O) Control of compensation volumes? (O) Hydraulic adequacy at all flows (O/M) Pump capacity (V/O) Pump standby capacity (V/O) Siltation (O/M) Exclusion of surface films/slicks (O) Gross solid/screenings removal (O) Ease of well isolation and impact on capacity (O) Hydraulic adequacy at all flows (O/M) Draw down at maximum pumping capacity (O/M) Pump capacity with respect to license (O) Turbidity issues (O/M) Cavitation issues (O) Air entrainment issues (O) Protection from surface contamination (O/M) Ease of well isolation and impact on capacity/quality (O/M) Hydraulic adequacy at all flows (O/M) Capacity of process with respect to loads and required standards (O/M) Distribution of flows over weirs (V/O) Ability to dose at all flow rates (O/M) Quality of control; automatic/manual (V/O) Level of storage (O) Frequency of blockages of dosing lines (O/M) Effectiveness of delivery area drainage (O) Ability to handle changes in raw water quality (O/M) Hydraulic adequacy at all flows (O/M) Capacity of process with respect to loads and required standards (O/M) Efficiency and distribution of air saturated water (V/O) Effectiveness of surface skimmer (O) Degree of solids depositions (O) Hydraulic adequacy at all flows (O/M) Capacity of process with respect to loads and required standards (O/M) Degree of mixing and flocculation retention prior to tank (O/M) Ability to maintain a stable sludge blanket (O) Efficiency of sludge remove facilities (O) Degree of turbidity and Ph measurement (V/O) Solids carry over (O) Ability to buffer poor clarification (O) Capacity of process with respect to loads and required standards, including with units off-line (O/M) Ability to achieve filter run-times (O/M) Presence/absence of turbidimeter (V/O) Quality of control (O) Quality of backwash (O) Signs of media growth (O/M) C-4

Asset Type Chlorination/dechlorination Wash Water and Sludge Disposal Distribution pumping/boosting Secondary disinfection Sewage force mains Sewage Pump Stations (including in let works pumping station) Inlet works Storm tanks Assessment criteria Specification of installation; telemetry, triple validation chlorine residual monitors, chlornine-time values and mixers, etc. (O) Control of residuals at all flow rates (M) Effectiveness of wash water settlement facilities (O) Quality of supernatant water produced with respect to consent standards (M) Effectiveness of sludge withdrawal and consolidation facilities (O) Facility to divert returned supernatant (O) Effectiveness of sludge dewatering (M) Degree of automation (V/O) Hydraulic output capacity (M) History or risk of service impacts; pressure or interruptions (M) Specification of installation; telemetry, triple validation chlorine residual monitors, chlorine-time values and mixers, etc. (O) Control of residuals at all flow rates (M) Hydraulic adequacy at all flows, including storm (O/M) Appropriate velocity maintained (O/M) Ease of access for maintenance (O) Septicity problems (O) Hydraulic adequacy at all flows (O/M) Capacity of pumps with respect to loads (O/M) Standby capacity (V/O) Capacity of sump and storm tanks (O/M) Ease of access for maintenance and emergency tinkering (O) Capacity to handle solids/rags (O) Blockage history (M) Service history with respect to upstream flooding or premature overflow (M) Overflow history with respect to events, loads, consent, and environmental impact (M) Service history with respect to odor and noise (M) Telemetry/alarms Hydraulic adequacy at all flows (O/M) Overtopping of screens and grit channel (O) Efficiency of screenings washing, dewatering, handling equipment (O) Return of organics to flow; from grit removal (O) Efficiency of grit removal (O/M) History of blockages (M) Suitability of screen size (O) Spillage inside and outside of structure (O/M) History of discharge to overflow with respect to events, loads, consents and environmental impact (M) History of complaints (M) Return arrangements (automatic?) and impact on downstream processes (O/M) Requirement for tank cleaning after use (O) Overtopping of structure (O) Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets C-5

Asset Type Primary settlement Biological filters Humus tanks Activated sludge plant Final tanks and RAS pumps Tertiary treatment Sludge reception and screening Assessment criteria Hydraulic adequacy at all flows (O/M) Carry over of solids (O) Efficiency of scum trapping and removal (O) Efficiency of sludge removal (O) Adequacy of sludge thickness (M) Presence of rising sludge, septicity or rising gases (O) Impact on inlet or outlet channels (O) Flow distribution over weirs and between units (V/O) Condition of media; blockages, etc. (O/M) Distribution and ventilation (O) Occurrence of ponding (O) Ability to buffer inefficient primary settlement stage (O) Condition of film (/M) Impact on downstream processes (O/M) Odor problems (O/M) Carry over of solids at all flows (O) Efficiency of scum trapping and removal at all flows (O) Efficiency of sludge production (required thickness) and removal (O/M) Presence of rising sludge, septicity or rising gases at all flows (O) Clarity of effluent (O/M) Backing up of inlet and outlet channels (O) Flow distribution between weirs and units (V/O) Impact on downstream processes (O/M) Hydraulic adequacy at all flows (O/M) Efficiency of mixing of settled sewage and returned activated sludge (RAS) (O) Distribution of air/oxygen (O/M) Efficiency of aeration control (O/M) Ability to buffer inefficient or over-loaded primary settlement stage (O/M) Ease of maintenance of mixed liquor suspended solids (O/M) Impact on works performance and downstream processes (O/M) Hydraulic adequacy at all flows (O/M) Carry over of solids (O) Ability to buffer inefficient or over-loaded upstream processes (O) Efficiency of scum trapping and removal (O) Presence of rising sludges, gases or septicity (O) Control of RAS and surplus sludges (O) Backing up of inlet/outlet channels (O) Flow distribution over weirs V/O) Clarity of effluent (O/M) Ability to buffer inefficient or over-loaded upstream processes (O) Clarity/quality of effluent (O/M) Adequacy of run times for solids filters (O/M) Efficiency of backwash/solids removal (O) Signs of media growth (O/M) Effectiveness (channeling of flow) and condition of grass plots and reed beds (V/O) Sufficiency of reception capacity with respect to economic tankering, considering normal demands and breakdowns/operational problems (O) Efficiency of sludge screens and handling equipment (O) C-6

Asset Type Sludge holding and consolidation tanks Sludge presses and mechanical thickening Sludge digestion Assessment criteria Occurrence of downstream problems or blockages from screenings (O/M) Ease of control/operation (O) Sufficiency of buffer holding capacity regarding economic tank sizing, considering normal demands and breakdowns/operational problems (O) Consolidation regarding percent dry solids target (M) Ease of control/operation (O) Occurrence of blockages (M) Environmental impacts (M) Complaints (M) Consolidation regarding percent dry solids target (M) Effectiveness of sludge feed and output equipment (O) Consistency of sludge production (O/M) Ease of control/operation (O) Occurrence of blockages (O/M) Consistency of sludge production (O) Stability of sludge (O/M) Adequacy of retention times (O) Efficiency of circulation, mixing, gas collection and holding, heating and heat exchange (O) Ease of control/operation (O) Occurrence of blockages (O/M) Environmental impacts (M) Complaints (M) Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets C-7

Appendix D A GENERIC CONDITION ASSESSMENT FORM FOR MECHANICAL AND ELECTRICAL EQUIPMENT Form prepared for the Washington Suburban Sanitation Commission s Industrial Assets Management Group by John W. Fortin; PSC member and Asset Management Consultant. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets D-1

Appendix E DEVELOPMENT OF A PROTOTYPE EXPERT SYSTEM Overview of Expert Systems An expert system (ES) is a software tool that attempts to simulate the reasoning applied by a human expert. The ES contains a knowledge base, a set of questions and a logical rule set, which are used to guide a non-expert through the diagnosis of a problem. ES have been widely applied in a number of areas, including assisting in medical diagnosis, computer troubleshooting and product selection. A well-designed ES provides the non-expert with an intuitive process for assessing a problem. However, the usefulness of an ES is limited by the difficulty of representing the knowledge, experience and logic of a human expert with a computer program. This inherent limitation means an ES is often used as a first cut approach, which focuses attention on the range of likely options. For example, in the context of this research, the output from an ES could be used prior to more detailed analysis, which would include an economic analysis of useable options and consideration of specific operational requirements. Design of the Expert System As noted above, a prototype ES was designed with the objective of enabling the selection of technically viable condition or performance assessment tools that are appropriate to the operational context. To achieve this, the ES designed for this project implemented the selection logic detailed in Chapter 6.0, Sections 6.2 and 6.3. However, the process was modified to reflect the way in which an expert would ask questions relating to the tool selection, based on its intended use and utility preferences. In line with the exclusion procedure detailed earlier, there are three distinct stages to the selection process, which for the purposes of the ES implementation are summarized as follows: Technical selection: Questions that narrow the selection of possible tools and techniques to those tools and techniques that are technically feasible. Operational selection: Questions that focus on the context of the assessment, which includes data availability, asset accessibility and importance to the network. Utility preferences: Questions that identify the preferences and the characteristics of the utility to undertake the assessment, which includes availability of technical skills, commercial status and level of technical support for the tool or technique. Figure D-1 provides a conceptual overview of the pathways that can be taken through the ES. The pathway the user follows is dependent on the purpose and focus of the assessment. As Figure D-1 shows, there are a number of key divergent points that separate pathways through the ES on the basis of factors such as service type, assessment, asset type, assessment focus, utility characteristics and operational context. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets E-1

Expert System Implementation A prototype ES was developed within the commercial package Expert System Builder (http://www.esbuilder.com/). This software package was selected because it is shareware and thus low cost. However, while suitable for a prototype version, the package has a number of limitations. The most significant limitation is the inability to exclude options on the basis of user s response to specific questions. For example, if the user indicates that only tools relevant to inspection of wastewater assets are of interest, then tools specific to drinking water assets are assigned a negative score, but are not removed from further consideration. However, the software package still provided an efficient way to rapidly develop a prototype ES that demonstrates the functionality and usefulness of the approach. An ES contains a knowledge base, a set of questions and a logical rule set. Expert System Builder has three modules that help to capture these components of the ES: Question editor: This module develops the structure of the questions to be used in distinguishing between feasible and unfeasible options. A key feature is the ability to create reliance so that the asking of a particular question is reliant on a response from a previous question. This ensures that only appropriate questions are asked. For example, if a user indicates focus on non-pipeline assets, all other questions related to pipelines are not asked. Knowledge acquisition: This module builds a database of knowledge that is used within the ES. The knowledge acquisition process involves answering each of the questions for each potential option. This process involves assigning a score for every possible question response. For example, if the option was Barcol Hardness test and the question related to granularity of assessment (the level within the asset stock the assessment is undertaken), then a response indicating the user was focused on network-wide assessment would be scored -10, while a response indicating the focus was asset specific would be scored +10. A don t know response has a neutral impact with a score of 0 assigned. User interface: The final module brings together the question file and the knowledge database within a user interface. The interface enables the user to navigate through the ES and input responses to each question. As the user moves through the ES, the scores for each question are aggregated. This combined score is then used to rank all options and identify the most appropriate tool or technique. The output result for the user is a list of all options ranked by confidence interval, with the most suitable options at the top of the list. E-2

Figure D-1. Conceptual Overview of Pathways in the Tool Selection Expert System. The following principles were applied in developing the ES prototype questions: Keep questions to a minimum and focus only on critical factors. Redundant questions were avoided; if the question did not narrow down the selection it was removed. Allow questions to be by-passed. If the user in unsure or does not have sufficient knowledge then they can move to the next question. Weighting of questions. Weighting was applied to ensure that critical questions had the greatest influence on the outcome. Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets E-3