DEVELOPMENT OF COMPUTERISED MAINTENANCE MANAGEMENT SYSTEM (CMMS) FOR READY MIX CONCRETE PLANT PRODUCTION FACILITIES

Transcription

1 DEVELOPMENT OF COMPUTERISED MAINTENANCE MANAGEMENT SYSTEM (CMMS) FOR READY MIX CONCRETE PLANT PRODUCTION FACILITIES THAYALAN A/L SUPRAMANI UNIVERSITI TEKNOLOGI MALAYSIA

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3 I hereby declare that I have read this thesis and in my opinion this thesis is sufficient in terms of scope and quality for the award of the degree of Master of Science (Construction Management) Signature :... Name of Supervisor :... Ir Dr. Rosli Mohamad Zin Date :... 4 April, 2005

4 DEVELOPMENT OF COMPUTERISED MAINTENANCE MANAGEMENT SYSTEM (CMMS) FOR READY MIX CONCRETE PLANT PRODUCTION FACILITIES THAYALAN A/L SUPRAMANI A project report submitted in partial fulfilment of the requirements for the award of the degree of Master of Science (Construction Management) Faculty of Civil Engineering Universiti Teknologi Malaysia April, 2005

5 I declare that this thesis entitled Development of Computerised Maintenance Management System (CMMS) for Ready Mix Concrete Plant Production Facilities is the result of my own research except as cited in the references. The thesis has not been accepted for any degree and is not concurrently submitted in candidature of any other degree. Signature :... Name : THAYALAN A/L SUPRAMANI Date : April 2, 2005

6 Especially dedicated to my father, mother and sisters also my special thanks to Dr. Prasad Kumar who help and encourage me in writing this report

7 vii ACKNOWLEDGEMENTS The author would like to acknowledge his supervisor, Ir Dr. Rosli Mohamad Zin, for the guidance, suggestions, and help given to me all through the process of doing this research, and also to his friends, Mr. Sai Sidharth and Mr. Senthuran, the software programmers, for all their help and advice. My grateful thanks also to all my friends and relatives who help me in completing this research project.

8 viii ABSTRACT The role of information technology is critical for plant maintenance optimization because it relies on the ability of the plant personnel to bring all data together in a coherent fashion for optimum analysis and decision-making. Equipment, be it sophisticated or basic in operation and design, depending on its usage, will inevitably malfunction and breakdown. Equipment maintenance need to be planned for, the possibility and probability of breakdowns and disruption to operations must also be considered when planning and scheduling production. The aim of this study is to develop a computerized maintenance management system (CMMS) that will improve conventional maintenance operation system at ready mix concrete plant production facilities. The initial stage of the study involved comprehensive literature reviews to gather the information of computerized maintenance management systems (CMMS) and batching plant production facilities maintenance information. The next stage was the development of an appropriate maintenance management system model for ready mix concrete plant production facilities and finally followed by prototype development. Validation of the developed CMMS model shows that the malfunction and breakdown of production facilities can be minimized through expert opinion in this same field. Generally, current manual ready mix concrete plant maintenance can be optimized through CMMS and more successful reliable plant maintenance can be achieved.

9 ix ABSTRAK Peranan teknologi maklumat dalam mengoptimakan penyenggaraan di kilang adalah kritikal sebab ia bergantung kepada pihak kilang yang terlibat untuk mengumpulkan data di dalam penganalisisan yang optima untuk membuat keputusan. Memang tidak dapat dinafikan bahawa walaupun jentera atau alatan yang mempunyai rekabentuk canggih atau asas dalam pengoperasian di kilang pada ketikanya akan mengalami kerosakan. Penyenggaraan ini perlu dirancang untuk mengetahui sebab atau kemungkinan kerosakan dialami kepada jentera selain mengambilkira gangguan yang berlaku kepada operasi jentera semasa perancangan untuk pembuatan. Tujuan kajian ini ialah untuk menghasilkan suatu sistem pengurusan penyenggaraan berkomputer (CMMS) untuk meningkatkan lagi sistem operasi penyenggaraan konvensional di kilang pembuatan konkrit sedia bancuh. Dalam peringkat awal, maklumat berkaitan dengan sistem pengurusan penyenggaraan berkomputer (CMMS) dan maklumat penyenggaraan fasiliti di kilang konkrit dikumpul melalui hasil dapatan kajian yang lain. Peringkat berikutnya adalah merekabentuk model sistem pengurusan penyenggaraan berkomputer (CMMS) yang sesuai dan diikuti dengan pembangunan model prototaip. Penilaian telah dibuat ke atas model yang telah dicipta oleh pakar di dalam bidang yang sama menunjukkan model sistem pengurusan penyelenggaraan berkomputer (CMMS) adalah efektif dalam mengurangkan kerosakan kepada fasiliti pembuatan kilang konkrit. Secara umumnya, kaedah manual dalam penyenggaraan kilang konkrit dapat dioptimakan lagi melalui penggunaan sistem pengurusan penyenggaraan berkomputer (CMMS) yang membolehkan keberkesanan penyenggaraan loji/peralatan dicapai.

10 x TABLE OF CONTENTS CHAPTER TITLE PAGE TITLE DECLARATION DEDICATION ACKNOWLEDGEMENT ABSTRACT ABSTRAK TABLE OF CONTENTS LIST OF FIGURES LIST OF TABLES ABBREVIATIONS i ii iii iv v vi vii xiii xvi xvii CHAPTER I INTRODUCTION Problem Statement Objectives of the Study Scope of the Study Methodology Arrangement of the Report 6

11 xi CHAPTER II LITERATURE REVIEW Manufacturing maintenance objectives Computer maintenance management systems Current Industrial Practices in the Area of CMMS Reliability Centered Maintenance (RCM) An information-processing model of maintenance management System Concept Development Phase Objective Tasks and Activities Study and Analyze the Business Need Plan the Project Form the Project Acquisition Strategy Study and Analyze the Risks Obtain Project Funding, Staff and Resources Document the Phase Efforts Review and Approval to Proceed Deliverables System Boundary Document Cost Benefit Analysis Feasibility Studies Risk Management Plan Phase Review Activity CMMS Model Approach Maintenance Process Maintenance Approach Maintenance Management Plan 36

12 xii Best Maintenance Practices Technical Strategy Probability of Failure System Bathtub Curve Reliability Modeling Management Strategy Maintenance Functional Mapping Strategic Maintenance Tools Batching Plant Equipment Maintenance Scales Water Meter Aggregate Bins Admixtures Automatic Controls Cement Silos Aggregates Heating System Features of Aggregate Hot Air Heating System Dust Collector Delivery Fleet Maintenance Mixer Maintenance Truck Mixer Maintenance Current Process involved in Operation at Ready Mix Concrete Production Process Modeling Tool of Ready Mix Concrete Plant Petri Net Model CYCLONE Model One-Plant-Multi site Model SDESA Modeling 83

13 xiii Schematic of Standard Ready Mix Concrete Plant Powder Silo Silo Pump Powder and/or Liquid Weigher Mixer Concrete Truck Mixer Skip Raw Material Storage Raw Material Weigher & Transport Control Room Standard Maintenance for Ready Mix Concrete Production Facilities 88 CHAPTER III RESEARCH METHODOLOGY Introduction Research Methodology Literature Review Data Collection Model Development Process Models Rapid Application Development (RAD) Modeling Dynamic Systems Development Method (DSDM) Modeling Programming Language 97

14 xiv Visual Basic MS Access Develop a Conceptual Modeling Develop Prototype Validation Conclusion and Recommendation 101 CHAPTER IV CMMS CONCEPTUAL MODEL DEVELOPMENT ON READY MIX CONCRETE PLANT Batching Control System in Ready Mix Concrete Plant Ready Mix Concrete Batching Process Description Integration of CMMS model in Ready Mix Concrete Plant Production Facilities Maintenance CMMS Core Modules CMMS Work Order of Functional Flow Diagram in Ready Mix Concrete Plant CMMS Work Order Flow Diagram in Ready Mix Concrete Plant Production Proposed Conceptual Model for Ready Mix Concrete Plant Production Facilities Management System 114 CHAPTER V READY MIX CONCRETE PLANT PRODUCTION FACILITIES MANAGEMENT SYSTEM PROTOTYPE DEVELOPMENT Context Diagram Data Flow Diagram Level 1 118

15 xv Data Flow Diagram Level 2: Login Process Data Flow Diagram Level 2: Location Module Data Flow Diagram Level 2: Work Order Module Data Flow Diagram Level 2: Machine Module Data Flow Diagram Level 2: Preventive Maintenance Module Data Flow Diagram Level 2: Masters Module Data Flow Diagram Level 2: Report Module 133 CHAPTER VI CONCLUSION AND RECOMMENDATION Conclusion Recommendation 138 REFERENCES 140

16 xiv LIST OF TABLES TABLE NO. TITLE PAGE 2.1 Maintenance Management Systems Support Maintenance Management Systems Processes 51

17 xv LIST OF FIGURES FIGURE NO. TITLE PAGE 1.1 Methodology of the Research Maintenance Costs The System Architecture of The Proposed RCM-based CMMS Integrated Solution System Concept Development Phase Activities Maintenance: A Process or A Function Maintenance Approach Maintenance Management Plan Best Maintenance Practice Technical Management Probability of Failure System Bathtub Curve Reliability Modeling Management Strategy Maintenance Functional Mapping Strategic Maintenance Tools Hoppers at Batching Plant Conveyor Carrying Aggregate to Hopper Diagram of Two Types of Hopper Systems 57

18 xvi 2.18 Beam Scale Spring Less Dial Type Scale Over-Under Indicator Water Meter Aggregate Bin Cross Section of Aggregate Bin Cross Section of Aggregate Hoppers Admixture Metering Device. (The dosage of admixture) The Automatic Controls Automatic Controls on when aggregates and cement are weighed on one scale Batching Control System Main Screen Interface at Batching Control System Cement Silos Cross Section of Cement Silos with all the Specifications Hot Air Heating System Dust Collector Mixing Blade Configurations Truck Mixer and Transit Truck Mixer Revolution Counter Concrete Production Process in Ready Mix Concrete Plant SDESA model schematic for one-plant-multi site RMC System Standard Ready Mix Concrete Plant Schematic of Standard Process in Ready Mix Concrete Plant Rapid Application Development Model Data Flow Diagram in Batch Control System Data Model Diagram of Overall Batching Control System Schematic for Process of Batch Control System to Batching System 106

19 xvii 4.4 Concrete Batching Processes in Ready Mix Concrete Plant CMMS Model in Ready Mix Concrete Plant Maintenance CMMS Core Modules Functional Flow Diagrams for Work Orders of Plant Maintenance in Ready Mix Concrete Plant Work Order Flow Diagrams for Plant Maintenance in Ready Mix Concrete Plant Proposed Conceptual Model for Ready Mix Concrete Plant Production Facilities Management System Context Diagram for Ready Mix Concrete Plant Production Facilities Management System Data Flow Diagram Level 1 for Main Menu in CMMS Model Main Menu for Ready Mix Concrete Plant Production Facilities Management System Prototype as in Data Flow Diagram Level Data Flow Diagram Level 2: Login Process The prototype Interface for Login Process Data Flow Diagram Level 2: Location Module The Prototype Interface for Line List in Location Module Data Flow Diagram Level 2: Work Order Module The Prototype Interface for Work Order List Data Flow Diagram Level 2: Machine Module The Prototype Interface for Machine List Data Flow Diagram Level 2: Preventive Maintenance Module The Prototype Interface for Preventive Maintenance Data Flow Diagram Level 2: Masters Module The Prototype Interface for Master List Data Flow Diagram Level 2: Report Module The Prototype Interface for Report Module 135

20 ABBREVIATIONS CMMS - Computerized Maintenance Management System PM - Preventive Maintenance RAD - Rapid Application Development RCM - Reliability Centered Maintenance PCM - Profit Centered Maintenance AM - Asset Management CBM - Condition Based Maintenance TPM - Total Productive Maintenance WCM - World Class Manufacturing AMT - Advanced Manufacturing Technology SBD - System Boundary Document CBA - Cost Benefit Analysis IPM - International Performance Measurements PT&I - Predictive Testing and Inspection CET - Critical Environment Technologies MTBF - Mean Time Between Failure MTTR - Mean Time To Repair HVAC - Heating, Ventilation, and Air Conditioning UCL - Upper Control Limit

21 CHAPTER I INTRODUCTION 1.0 Introduction Computerised Maintenance Management Systems (CMMS) are increasingly being used to manage and control plant and equipment maintenance in modern manufacturing and construction services industries. This view of the selection and implementation process can assist those who are considering CMMS for the first time, to decide their requirements. A number of years ago, the principles of CMMS were applied to hospital equipment maintenance, where critical breakdowns could lead to the development of life threatening situations. In recent years private companies have come to recognize the value of these systems as a maintenance performance and improvement tool. The advent of the PC during the last few years has further boosted their popularity. As more and more maintenance personnel become computer literate they are regarded as an increasingly attractive option. Companies are also investing in CMMS because they are generally designed to support the document control requirements of ISO 9002.

22 Some of the standard functions available from a CMMS are discussed later in this document and those who have had no previous exposure to CMMS will find this useful. However, in essence, a CMMS may be used to: Control the company s list of maintainable assets through an asset register Control accounting of assets, purchase price, depreciation rates, etc. Schedule planned preventive maintenance routines Control preventive maintenance procedures and documentation Control the issue and documentation of planned and unplanned maintenance work. Organize the maintenance personnel database including shift work schedules Schedule calibration for gauges and instruments Control portable appliance testing Assist in maintenance project management Provide maintenance budgeting and costing statistics Control maintenance inventory (store's management, requisition and purchasing) Process condition monitoring inputs Provide analysis tools for maintenance performance. 1.1 Problem Statement Computerised Maintenance Management Systems (CMMS) at batching plant for ready mix concrete based on software methodology will be able to delivers various benefits to organizations by delivering information to maintenance engineers and managers. It is also an equipment preventive / inspection maintenance planning and

23 scheduling allows for automatic generation of preventive / inspection work orders. Nevertheless in actual working environment, it is very difficult for plant managers at batching plant to monitor and control overall maintenance for batching plant. This is because there is no computerized maintenance management system implemented at current batching plant to reduce the breakdown time and best maintenance practices. Normally during the maintenance for batching plant, the maintenance department will usually engaged with the manual maintenance operation by typical paper system, each piece of equipment or asset will have a history card or file. This procedure of maintenance is done according to time lapse or any breakdown of equipment at plant. There are no maintenance optimisation computerised system is triggered for a particular system or set of symptoms if any failure occurs at plant. Maintenance using CMMS in batching plant will assist to highlight the levels of downtime and reduce costs even though there were no supports from top management to implement other best maintenance practices. Apart from that, CMMS control spares module to reduce spares and still have parts on hand for plant facilities maintenance. For problems associated with maintenance personnel excelling at some jobs and lacking skills in other craft areas. CMMS allows managers to review information related to what work has been done and by who over a period and assign work appropriately in a variety of craft areas in the future. In cases where not enough maintenance personnel to handle the work load, CMMS can generate reports on labour requirements for each work order totalling the information by craft and week, showing imbalances and requirements for additional personnel. CMMS can provide reports for each item of equipment for breakdown just before preventative maintenance which can help pinpoint problem parts or requirements to reduce the preventative maintenance interval.

24 1.2 Objectives of the Study The aim of this study is to develop a Computerised Maintenance Management System (CMMS) that will improve conventional maintenance operation system in ready mix concrete plant production facilities. To achieve this aim of the study, the following objectives have been determined: 1. To identify the current or conventional maintenance system at ready mix concrete plant; 2. To propose a Computerized Maintenance Management System (CMMS) model at ready mix concrete plant; and 3. To develop Computerized Maintenance Management System (CMMS) prototype. 1.3 Scope of the Study The scopes of the study are as follows: 1. The study focused on the Computerised Maintenance Management System (CMMS) used in Wet and Dry Ready Mix Concrete Plants; and 2. The Computerised Maintenance Management System (CMMS) only cover common maintenance work progress items that used in wet and dry ready mix concrete plants for production facilities such batching equipment, batching

25 control system, machines, preventive maintenance (PM) scheduling, automatic work order generation, and data integrity for report. 1.4 Methodology Detail discussion on methodology of the study is given in chapter III. Generally the flow diagram of methodology of the study is as shown below. Determining Objective and Scope Literature Review Interview and Expert Opinion Identifying Problem statement Develop Conceptual Modeling Develop Prototype Validation Conclusion and Recommendation Figure 1.1 Methodology of the Study

26 1.5 Arrangement of the Report follows: This research which is the result of a master s project report was arranged as a. Chapter I: Introduction. In this introduction the problem statement, scope of the study and limitation and arrangement of the report was explained. b. Chapter II: Literature Review. This chapter is a discussion on literature in order to understand the function of CMMS model, benefit of CMMS model and role of CMMS model in maintenance for plant production facilities in ready mix concrete plant, specifically discusses the concrete batching plant equipment maintenance which required by CMMS model to carrying out plant production facilities maintenance. c. Chapter III: Research Methodology This section consists of a discussion on how research is carried out according to four steps chronologically, i.e.: the literature review, data collection obtained by interviewing the ready mix concrete plant managers and technicians who involved in plant maintenance, then the data collected are input to the CMMS model prototype to obtain the result of the research and finally conclusion and recommendation are made.

27 d. Chapter IV: CMMS Conceptual Model Development The conceptual model for CMMS was developed using data flow diagram from data collection in concrete batching plant which are then verified for CMMS prototype development. e. Chapter V: CMMS Prototype Model Development The CMMS prototype model was developed based on the conceptual model using Microsoft Access for interfaces and Visual Basic programming language for prototype coding. f. Chapter VI: Conclusion and Recommendation This last chapter consists of the conclusion of the result of the research and recommendation to improve CMMS prototype model for ready mix concrete plant production facilities maintenance.

28 CHAPTER II LITERATURE REVIEW 2.1 Manufacturing Maintenance Objectives Considerable sums of money are wasted in business annually, because of ineffective or poorly organised maintenance. However, maintenance is only one element, which contributes to effective operation during the life cycle of an item of equipment. Maintenance has a very important part to play, but must be coordinated with other disciplines such as training personnel in appropriate skills, maintaining motivation and effective people management. Taken together, this approach aimed at achieving economic life-cycle cost for an item has been called terotechnology, and defined by Wild (1995) as the multidisciplinary approach to the specification, design, installation, commissioning, use and disposal of facilities, equipment and buildings, in pursuit of economic life-cycle costs. The formal definition of terotechnology according to the British Standard, BS 3811:1984 is a combination of management, financial, engineering, building and other practices applied to the physical assets in pursuit of economic life cycle costs.

29 9 Williams, Davies and Drake (1994) go on to clarify this definition by stating that terotechnology is concerned with the specification and design for reliability and maintainability of plant, machinery, equipment, buildings and structures, with their installation, commissioning, operation, maintenance, modification and replacement, and with feedback of information on design, performance and costs. Hodges (1991) simplifies these definitions by explaining terotechnology as the achievement of the best value for money using techniques which are many and various in their forms, approach and application. The objective of maintenance is to try to maximise the performance of equipment by ensuring that, items of equipment function regularly and efficiently, by attempting to prevent breakdowns or failures, and by minimising the losses incurred by breakdowns or failures. In fact, it is the objective of the maintenance function to maintain or increase the reliability of the operating system taken as a whole. Sivalingam (1997) discusses the importance of maintenance within the broader area of industrial management. He states an integrated maintenance management when properly implemented can lessen emergencies by 75%, cut purchasing by 25%, increase warehouse accuracy by 95% and improve preventative maintenance by 200%. He goes on to say, with maintenance costs rising from 9% to 11% per annum, the potential for savings is very high in the short and long term. Good management of maintenance can reduce costs by as much as 35%. Wild (1995) draws the familiar total cost curve as in Figure 2.1, which shows that increased effort in preventative maintenance should reduce the cost of repair. If it were possible to define both of these curves, then it would be a simple task to determine the minimum cost maintenance policy. However, it is not as clear-cut as this and therefore maintenance policy is much more difficult to formulate.

30 10 Figure 2.1 Maintenance Costs (Source: Wild, 1995) The overall objective is to minimise the total cost of maintenance by minimising one or both of the costs that contribute to it. Reducing the cost of preventative maintenance (PM) by minimising the level of PM carried out in the manufacturing facility can increase downtime due to breakdowns and consequently necessitate the need for more repairs. On the other hand, increasing the level of PM to too high a level will introduce unnecessary extra maintenance cost without necessarily minimising the risk of breakdown. The overall objective is to obtain an optimum level of preventative maintenance so as to reduce total maintenance cost. Achieving this optimum delivers other benefits such as increased morale, reduction in random breakdowns, improved quality of product, increased equipment availability, reduced delivery times and of course increases in profitability. The strategies utilised successfully in the area of maintenance management optimisation include Reliability Centred Maintenance (RCM), Profit Centred Maintenance (PCM), Asset Management (AM), Condition Based Maintenance (CBM),Total Productive Maintenance (TPM) and World Class Manufacturing (WCM) through CMMS implementation. These management philosophies essentially comprise of different techniques and tools with varying emphasis on individual factors, but achieve a very similar final objective, the optimisation of maintenance. The goal is to obtain the maximum production output with the best levels of product quality, and doing

31 11 this at minimum cost to the facility providing the least risk of breakdown. Other important criteria of modern maintenance include such topics as safety to personnel, the environment and morale of employees. 2.2 Computer Maintenance Management Systems Corder (1976) gives an insight into the scope of modern maintenance management, maintenance management is very wide indeed, since almost all current engineering, management and accounting practices have some relevance to the subject. Greater demands are being imposed on the maintenance manager in order to improve the standard of maintenance and efficiency of work while at the same time reducing maintenance operational costs. Chapman (1993) states that CMMS software was seen first around Today it is widely used in manufacturing plants all over the world. Maintenance optimisation is greatly facilitated when companies adopt a World Class Manufacturing/Maintenance (WCM) philosophy or management strategy in conjunction with CMMS implementation. There are many factors, which influence management on installing CMMS software and using it within their plants. Trunk (1997) puts forward the following reasons for adopting CMMS software: Customers demand compliance with ISO 9000; The FDA requires maintenance management systems for plants that handle pharmaceuticals; and Insurance companies demand to know cost and condition of material handling assets.

32 12 Chapman (1993) states, the tracking and control of plant maintenance and outage activities involve objectives and requirements which are different from the control of normal engineering and construction work. The integration of these requirements into a computerised management information and control system challenges the system designed. Maintenance and outage work is estimated, scheduled and controlled at a much greater level of detail than normally required on a typical engineering and construction project. The variety of tasks associated with the organization of maintenance management lends itself to the utilisation of computer systems. It is in this area including planning, organisation and administration of maintenance management that Computer Maintenance Management Systems (CMMSs) have proved to be very beneficial. Lamendola (1998) emphasizes the need to eliminate non-value added activities especially with respect to documentation of work within maintenance. He states that this philosophy has long been the essence of Computerised Maintenance Management Systems. Travis and Casinger (1997) outline other difficulties associated with modern maintenance management. In their paper they prioritise the top five problems encountered by maintenance managers and suggest that CMMS is the solution to these problems. The problems are outlined as follows: a. Little or no support from management to implement world class maintenance practices, CMMS reports can highlight the levels of downtime and reduce costs; b. Inventory problems, the need to reduce spares and still have parts on hand. Control of spares modules is part of most of the modern CMMS packages; c. The problems associated with maintenance personnel excelling at some jobs and lacking skills in other craft areas. CMMS allows managers to review this information, what work has been done and by who over a period and assign work appropriately in a variety of craft areas in the future;

33 13 d. Not enough maintenance personnel to handle the workload. CMMS can generate reports on labour requirements for each work order totalling the information by craft and week, showing imbalances and requirements for additional personnel; and e. Machines breakdown just before preventative maintenance is due CMMS can provide reports for each item of equipment, which can help pinpoint problem parts or requirements to reduce the preventative maintenance interval. Wireman (1994) is of the opinion that if Computer Maintenance Management Systems are to be properly examined it is important to have an understanding of the primary maintenance functions incorporating: maintenance inspections and service, equipment installation, maintenance storekeeping, craft administration. He goes on to outline the objectives of CMMS covering: improved maintenance costs, reduced equipment downtime as a result of scheduled preventative maintenance, increased equipment life, ability to store historical records to assist in the planning and budgeting of maintenance, ability to generate maintenance reports. Most of CMMS systems have four modules or components catering for: a. work order planning and scheduling; b. maintenance stores controls; c. preventative/predictive maintenance; and d. maintenance reporting. A committee should head the selection process according to Wireman (1994) with members from engineering, maintenance, stores, accounting and data processing. The objectives of these committees include: a. Review of present record keeping systems and paper work flow;

34 14 b. Planning objectives of the system in the areas of: work order processing, maintenance stores, preventative maintenance, cost controls and required reports; c. Identifying the types of computer systems that are needed; d. Identifying the vendor packages that meet the objectives; and e. Evaluation of systems and vendors. 2.3 Current Industrial Practices in the Area of CMMS Industries such as oil and gas or nuclear power plants are in need of an efficient computerized maintenance management system to manage their maintenance activities throughout the plant lifecycle. The major problem that faces the implementation of CMMS is that the maintenance strategies are either reflected from the equipment vendor, from similar plants, or from the design environment. The changes in the operating condition are not fully reflected into the maintenance strategies, which are configured within CMMS. From the above-mentioned background points, the research work offers an automated RCM as integrated with CMMS as part of the plant enterprise engineering environment. The consolidation of some useful reliability and maintainability methods and models will enhance consolidation of some useful reliability and maintainability methods and models will ensure the effectiveness of the proposed solution. In this study, the system architecture of the integrated solution is presented to show the mechanism of the proposed solution.

35 15 Towards the proper analysis of the solution, business activity models have been developed, which reflects the different activities involved in performing the RCM assessment. The main modules of the proposed RCM computerized module as well as the function decomposition of the integrated solution are identified. The implementation aspects of the proposed solution will be discussed as an adopted CMMS. 2.4 Reliability Centred Maintenance (RCM) The concepts behind RCM are not new, having their origin in the airline industry back in the 1960s. After several years of experience, in 1978, the US Department of Defence issued the MSG-3, an Airline/Manufacturers Maintenance Program Planning Document. That year, Nowlan and Heap (1978) wrote a comprehensive document on the relationships among Maintenance, Reliability and Safety, entitled Reliability Centred Maintenance, creating the RCM methodology. RCM spread throughout industries, specially those needing safety and reliability, during the 1980s and the 1990s, being now extended to several industry fields. In short, RCM can be defined as a systematic approach to systems functionality, failures of that functionality, causes and effects of failures, and infrastructure affected by failures. Once the failures are known, the consequences of them must be taken into account. Consequences are classified in: safety and environmental, operational (delays), non-operational and hidden failure consequences. Later, those categories are used as the basis of a strategic framework for maintenance decision-making. The decision-making process is used in order to select the most appropriate task to maintain a system filtering the proposed classification of consequences through a logic decision tree. In the 1970s, and still today, RCM was a major challenge in many industries because it changed the focus of PM from bringing back the systems to a perfect state to maintaining the system in a good functional state (within some defined operational limits).

36 16 RCM methodology and has three major goals. First one is to enhance safety and reliability of systems by focusing on the most important functions. RCM is concerned mainly with what we want the equipment to do, not what it actually does. Second is to prevent or to mitigate the consequences of failures, not to prevent the failures themselves. The consequences of a failure differ depending on where and how items are installed and operated. Third one is to reduce maintenance costs by avoiding or removing maintenance actions that are not strictly necessary. It is no longer assumed that all failures can be prevented by PM, or that even if they could be prevented, it would be desirable to do so. In the early 1960s, the initial reliability centred maintenance (RCM) development was done by the North American civil aviation industry. RCM process is intended to determine the most realistic and optimised maintenance requirements of any physical asset to continue its stated operating condition. Many industries have adopted RCM technique to solve many confronted maintenance problems. Unfortunately, it did not work as expected for many reasons: RCM is a time- and effort-consuming process and requires considerable amount of resources, especially for large number of assets for complex plants; the available information is not adequate to decide the suitable maintenance strategy and to optimize its cost as maintenance and operational systems are isolated from design and engineering systems; there are nonengineering factors involved in the maintenance problems i.e. management and human factors. To overcome some of the highlighted maintenance problems an integrated RCM-CMMS system is proposed so that it can dynamically change the maintenance strategies based on the operating condition of the equipment and other factors affecting the life (age) of the underlying assets (W. Pujadas and F.F. Chen, 1996). An automated RCM as integrated with CMMS as part of the plant enterprise engineering environment. The consolidation of some useful reliability and maintainability methods and models will enhance consolidation of some useful reliability and maintainability methods and models will ensure the effectiveness of the proposed solution. The system architecture of the integrated solution is presented in Figure 2.2 to show the mechanism of the proposed solution. Towards the proper analysis of the solution, business activity models have been developed, which reflects the

37 17 different activities involved in performing the RCM assessment. The main modules of the proposed RCM computerized module as well as the function decomposition of the integrated solution are identified. The system architecture of the proposed RCM-based CMMS integrated solution. The proposed automated solution includes four main processes: plant design environment [P1], RCM process [P2], CMMS [P3], and operational systems [P4]. The integration with design environment is essential as most of the maintenance strategies are initially decided during the process design stage. RCM component is an expert system that decides the optimum maintenance strategies and calculates the different quantitative parameters of maintenance tasks. CMMS component is mainly used during the operation stage to manage and implement maintenance strategies via extracting asset information along with their functions from design environment (i.e. from the design model). RCM utilizes asset information along with design and operational data/knowledge to perform asset and failure assessments and to build the failure and risk data/knowledge bases.

38 18 Figure 2.2 The System Architecture of the Proposed RCM-Based CMMS Integrated Solution (Source: Gabbar, 2003) 2.5 An Information-Processing Model of Maintenance Management Changes in the production environment have made the task of making decisions about allocating maintenance resources and scheduling maintenance work more difficult. More variables and consequences must be considered requiring increased information-processing capacity. Information-processing model is applied to study how the maintenance function applies different strategies to cope with the environmental

39 19 complexity. Based on data from a survey of plant managers, the analysis shows that maintenance responds to the complexity of its environment with the use of computerized maintenance management systems, preventive and predictive maintenance systems, coordination and increased workforce size (Galbraith., 1977) The maintenance function is critical to a manufacturing organization's ability to maintain its competitiveness. Without well-maintained equipment, a plant will be at a disadvantage in a market that requires low-cost products of high quality to be delivered quickly. Properly maintained equipment will have higher availability and longer life. Poorly maintained equipment will fail frequently and need to be replaced sooner. Additionally, poorly maintained equipment is less likely to produce products of consistent quality. Changes in the production environment have made the maintenance task increasingly complex. Higher levels of automation can make diagnosis and repair of equipment more difficult (Robinson, 1987; Paz and Leigh, 1994). The high level of capital intensity associated with automated equipment also places greater pressure on the maintenance function to rapidly repair equipment and to prevent failures from occurring ( Collins and Hull, 1986). All of this complexity makes the decisions about allocating resources and scheduling work more difficult for maintenance. More variables and consequences must be considered requiring increased organizational capacity for information processing to support the ability to make quick and accurate decisions. A study by Flynn and Flynn (1999) looked at the impact of complexity on manufacturing organizations. Their findings demonstrated that manufacturing organizations did indeed cope with complexities by employing practices that reduced the

40 20 need for information processing or increased the organization's capacity for information processing. The model used by Flynn and Flynn (1999) is applied more narrowly to the maintenance function. The model used in the Flynn study draws on the informationprocessing model introduced by Galbraith (1977). Galbraith's model proposes that organizations cope with complexity through different information-processing strategies. Galbraith (1977) defines uncertainty as the gap between the amount of information required to perform a task and the information already possessed by the organization. Complexity results in problems that are more difficult to understand or analyze, resulting in greater uncertainty (Perrow, 1967). Increased complexity has the potential to affect the organization adversely resulting in reduced performance (Flynn and Flynn, 1999). Flynn and Flynn (1999) proposed an expanded set of factors that may contribute to internal uncertainty in manufacturing organizations. These factors include manufacturing diversity and process diversity. Manufacturing diversity includes characteristics such as variability of demand patterns and the complexity of the products being produced. Process diversity is determined by the characteristics of process technology (i.e., job shop, batch, continuous) in use as well as the product volume/variety trade-offs found in the product process matrix. Process diversity is also important to the maintenance function because it describes the actual equipment that the maintenance function is responsible for maintaining. Studies have found that mass output orientation impacts the overall supporting infrastructure for manufacturing organizations (Woodward, 1965; Blau et al.,

41 ; Ward et al., 1992). More recently, studies have found that organizational adjustments are required in order to successfully implement advanced manufacturing technologies ( Dean and Snell, 1991; Nemetz and Fry, 1988). Logically, it may be assumed that this effect may be extended to the organizational structure and practices of specific functions within manufacturing. Further, the use of advanced manufacturing technology (AMT) has been found to be associated with maintenance practices that support communication and coordination and technical expertise within the organization ( Swanson, 1999). In Galbraith's model (1977), complexity has a direct effect on an organization's information-processing needs. Organizations have two alternatives for coping with complexity. The first alternative is to reduce the need for information processing. The second alternative is to increase the organization's information-processing capacity. Specific maintenance practices are consistent with the information-processing alternatives discussed by Galbraith. Preventive maintenance is work performed after a specified period of time or machine use (Gits, 1992). Preventive maintenance restores equipment condition in order to avoid more catastrophic failures that would cause more extended downtime. Predictive maintenance is based on the same principle as preventive maintenance. Under predictive maintenance, diagnostic equipment is used to measure the physical condition of equipment such as temperature, vibration, lubrication and corrosion. When one of these indicators reaches a specified level, work is undertaken to restore the equipment to proper condition ( Vanzile and Otis, 1992; Herbaty, 1990). Preventive and predictive maintenance provide the maintenance organization with a more predictable and manageable workload. These practices also allow the production function to more easily determine its ability to fill orders on time. This

42 22 ability is especially important as the diversity of equipment to be maintained and the number of different types of workers to be managed increases. Galbraith's (1977) third approach to reducing information-processing requirements is to use self-contained tasks. With self-contained tasks, groups are created with each group being provided with sufficient resources to perform its own task. Flynn and Flynn (1999) used group technology as an example of self-contained tasks in a manufacturing environment. Group technology assigns a group of machines to produce a specific set of products rather than the universe of product offerings. For maintenance, one way to create self-contained tasks is through the use of decentralized, area maintenance crews. In many plants, maintenance workers are dispatched from a central shop. By creating area maintenance crews assigned to specific plant areas, the maintenance function reduces complexity by dedicating crews to specific areas of the plant rather than trying to juggle and meet the needs of multiple production areas with a single, central shop (Heintzelman, 1976). Galbraith (1977) proposed two methods for increasing an organization's information-processing capacity. The first method involves investments in vertical information systems. According to Galbraith, vertical information systems allow an organization to process information without overloading the organization's normal communication channels. A computer information system is one example of a vertical information system. The value of vertical information systems is that their capabilities for supporting communication and decision making mean that fewer exceptions are referred upward in the organizational hierarchy. In maintenance, there has been an increasing movement toward computerized maintenance management systems (CMMS). CMMS assists in managing a wide range of information on the maintenance workforce, spare-parts inventories, repair schedules

43 23 and equipment histories. It can also be used to automate the preventive maintenance function, and to assist in the control of maintenance inventories and the purchase of materials. CMMS may also be used to plan and schedule work orders and to manage the overall maintenance workload (Hora, 1987; Wireman, 1991). Another capability offered by CMMS is the potential to strengthen reporting and analysis capabilities ( Wireman, 1991; Callahan, 1997; Hannan and Keyport, 1991). Finally, CMMS has been described as a tool for coordination and communication with production ( Dunn and Johnson, 1991). While the capabilities offered by CMMS do not in any way reduce the amount of information to be processed by the maintenance organization, they do assist the maintenance function in managing the ever increasing complexity brought about by more complex and varied technologies and a workforce with highly specialized skills. The use of computerized information systems by the maintenance function will be higher in plants with greater environmental complexity. Galbraith (1977) also suggested that lateral relations assist in increasing information-processing capacity. Lateral relations allow problems to be solved at the level that they occur rather than being passed up the organizational hierarchy. As a support function, maintenance must communicate and coordinate effectively with production. All of the proposed types of lateral relations may be used to create links between maintenance and production. As the production environment becomes more complex, coordination between maintenance and production becomes more critical and may require the use of more than one type of lateral relation in order to effectively support the ability to maintain quality and meet production schedules. For this study, a plant level measure of maintenance performance was needed. At the plant level, maintenance performance is evident in equipment availability, the ability

44 24 to meet production schedules and product quality (Pintelon and Gelders, 1992; Teresko, 1992; Macaulay, 1988). However, in the case of plant equipment condition and availability, uniform plant-level measures of maintenance performance are difficult to identify. It is only in the past few years that researchers have started to discuss uniform methods of measuring maintenance performance ( Arts et al., 1998; Tsang, 1998). Many plants track equipment downtime on individual pieces of equipment, but overall plant indicators of downtime are often not available. The hypotheses concerning the relationship between environmental complexity and maintenance organization and maintenance practices were tested using hierarchical regression analysis (Cohen and Cohen, 1975). Hierarchical regression allows groups of variables to be entered into the regression equation in steps. The first group of variables is allowed to explain as much of the variability of the dependent variable as possible. As subsequent variables are entered, the amount of variance of the dependent variable that is explained by the newly entered independent variables is calculated. The variables describing the plant environment (plant size and union status) were entered in the first step. In the second step, the production technology variables measuring production technology characteristics were entered. In the third step, variables measuring the number of maintenance classifications and number of levels in the maintenance organization were entered. A significant incremental R 2 in the second or third step could be interpreted as support for the hypotheses that there are relationships between production technology or maintenance organization and maintenance practices. The F- statistics reported in the tables are incremental. That is, they are associated with the change in R 2 occurring when the variables were entered. The variables were measured so that positive 's are consistent with the hypotheses. Positive 's would indicate that plants with greater complexity would make more extensive use of the particular maintenance practice than plants with lower levels of complexity. The form of the regression equation is shown below:

45 25 MtcPrac i = 0 +( 1 Size i + 2 Unionization i )+( 3 VARI i + 4 AMT i + 5 MASS i )+( 6 CLASS i + 7 LEVEL i )+ I ( (Equation1) CMMS and lateral relations to increase information-processing capacity were used in response to the use of AMT. It also appears that some of the informationprocessing alternatives used by maintenance in response to complexity contribute to improved maintenance performance. AMT was strongly associated with several maintenance practices. AMT such as flexible manufacturing systems replace both physical human effort and some mental human effort. Introduction of AMT means that equipment is more complicated to maintain (Robinson, 1987). AMT implementation also means that production steps that were previously distinct may be combined into a single operation. Increased integration means that equipment failures lead to more immediate and costly consequences ( Finch and Gilbert, 1986; Walton and Susman, 1987). Therefore, maintenance resources must be quickly and properly directed to solve problems. AMT was strongly associated with the use of CMMS. The informationprocessing capabilities of CMMS provide the ability to quickly communicate and coordinate the need for repairs. This result also makes sense in that organizations with computer-assisted manufacturing technologies would be very comfortable with using a computer-based system for communicating and coordinating maintenance activities. 2.6 System Concept Development Phase

46 Objective System Concept Development begins when the Concept Proposal has been formally approved and requires study and analysis that may lead to system development activities. The review and approval of the Concept Proposal begins the formal studies and analysis of the need in the System Concept Development Phase and begins the life cycle of an identifiable project Tasks and Activities The following activities are performed as part of the System Concept Development Phase. The results of these activities are captured in the four phase documents and their underlying institutional processes and procedures (See Figure 2.3).

47 27 Figure 2.3 System Concept Development Phase Activities (Source: Ghanalingam, 2003) Study and Analyse the Business Need The project team, supplemented by enterprise architecture or other technical experts, if needed, should analyse all feasible technical, business process, and commercial alternatives to meeting the business need. These alternatives should then be analysed from a life cycle cost perspective. The results of these studies should show a range of feasible alternatives based on life cycle cost, technical capability, and scheduled availability. Typically, these studies should narrow the system technical approaches to only a few potential, desirable solutions that should proceed into the subsequent life cycle phases.

48 Plan the Project The project team should develop high-level (baseline) schedule, cost, and performance measures which are summarized in the System Boundary Document. These high-level estimates are further refined in subsequent phases Form the Project Acquisition Strategy The acquisition strategy should be included in the System Boundary Document (SBD). The project team should determine the strategies to be used during the remainder of the project concurrently with the development of the Cost Benefit Analysis (CBA) and Feasibility Study. Will the work be accomplished with available staff or do contractors need to be hired? Discuss available and projected technologies, such as reuse or Commercial Off-the-Shelf and potential contract types Study and Analyse the Risks Identify any programmatic or technical risks. The risks associated with further development should also be studied. The results of these assessments should be summarized in the SBD and documented in the Risk Management Plan and CBA Obtain Project Funding, Staff and Resources

49 29 Estimate, justify, submit requests for, and obtain resources to execute the project in the format of the Capital Asset Plan and Justification Document the Phase Efforts The results of the phase efforts are documented in the System Boundary Document, Cost Benefit Analysis, Feasibility Study, and Risk Management Plan Review and Approval to Proceed The results of the phase efforts are presented to project stakeholders and decision makers together with a recommendation to (1) proceed into the next life-cycle phase, (2) continue additional conceptual phase activities, or (3) terminate the project. The emphasis of the review should be on (1) the successful accomplishment of the phase objectives, (2) the plans for the next life-cycle phase, and (3) the risks associated with moving into the next life-cycle phase. The review also addresses the availability of resources to execute the subsequent life-cycle phases. The results of the review should be documented reflecting the decision on the recommended action.

50 Deliverables The following deliverables shall be initiated during the System Concept Development Phase: System Boundary Document Identifies the scope of a system (or capability). It should contain the high level requirements, benefits, business assumptions, and program costs and schedules. It records management decisions on the envisioned system early in its development and provides guidance on its achievement Cost Benefit Analysis Provides cost or benefit information for analysing and evaluating alternative solutions to a problem and for making decisions about initiating, as well as continuing, the development of information technology systems. The analysis should clearly indicate the cost to conform to the architectural standards in the Technical Reference Model (TRM) Feasibility Studies

51 31 Provides an overview of a business requirement or opportunity and determines if feasible solutions exist before full life-cycle resources are committed Risk Management Plan Identifies project risks and specifies the plans to reduce or mitigate the risks Phase Review Activity The System Concept Development Review shall by performed at the end of this phase. The review ensures that the goals and objectives of the system are identified and that the feasibility of the system is established. Products of the System Concept Development Phase are reviewed including the budget, risk, and user requirements. This review is organized, planned, and led by the Program Manager and/or representative. 2.7 CMMS Model Approach We all know how much rests on our physical and financial well being. Good health, your own and your company s, depends on keeping all parts in proper working

52 32 order. Therefore, it s surprising so many organizations neglect one of the essential elements of success not paying enough attention to maintenance. Another flaw in the human character is that everybody wants to build, and nobody wants to do maintenance ( Kurt Vonnegut, 1974). The total cost of maintenance surprises many senior executives and managers. Although it varies directly with the capital intensity of the business, maintenance can account for half of production costs. Mining accounts for 20-50% of costs, manufacturing 5-15%, and processing 3-15%. In addition, this estimate excludes the sales value of lost production and costs associated with rework, rejected products, or recycled materials. Maintenance strategies can add significant value and increase asset effectiveness and reliability. Effectively integrated into CMMS strategies ensure: Equipment life-cycle productivity; Optimum mix of maintenance, according to criticality, value, and risk; Performance measurements over time; and Reliability engineering through information management Maintenance Process Maintenance management strategies on the premise that maintenance is a process. Maintenance is a set of linked activities requiring a series of inputs that transforms them into a set of outputs, rather than a function simply requiring the application of resources.

53 33 When the maintenance became as a function, then optimise the function and not the overall process. Maintenance as a function usually covers only the trades. As a process, it not only covers trades, but also purchasing, stores, scheduling, operations, engineering, and several other management and administrative functions. When the approach maintenance as a function, a number of problems arise. One example is stores. Because equipment availability is the backbone of maintenance as a function, it cannot afford to be caught without parts on hand to respond to breakdowns. Maximizing inventory optimises its performance as a function. It minimizes freight charges for the materials and minimizes personnel costs but can slow the procurement process. The prime driver for this function is control, not necessarily service. The purchasing function entails going out for numerous quotes and taking the lowest cost. While this approach meets the minimum specifications and cost savings targets, it adds excessive variation in spare parts. The solution to this problem is to view equipment effectiveness and cost efficiency as results of the entire maintenance process as depicted in Figure 2.4. This can only be done by developing standards that get the most from all functions, not any particular one.

54 34 Figure 2.4 Maintenance: A process or a function ( Source: Kurt Vonnegut, 1974) Maintenance Approach Based on the Figure 2.5 for maintenance approach involves: Establishing a plan with clear guidelines that define the required scope of maintenance through customer requirements; Identifying operational effectiveness required to accomplish the maintenance program;

55 35 Providing a clear understanding of the maintenance functions and processes as they relate to the systems and tool applications; Developing performance evaluation criteria and benchmark goals; and Defining an organizational structure which best meets the customers requirements and key results. Figure 2.5 Maintenance Approach ( Source: Kurt Vonnegut, 1974) Approach to maintenance provides the general framework by which the overall maintenance program is established and provides specific direction for the various functions and processes. The important aspects of this approach are two-fold:

56 36 It causes more significant decisions (i.e., manpower, budget, and organization) to be made by those having both responsibility and authority for implementation. It provides basic guidance for maintenance operations (i.e., the use of contract maintenance, the level of training required for personnel, the use of specialized support programs for critical equipment, and standard maintenance processes). As illustrated in Figure 2.5 for maintenance approach, the maintenance approach can be summarized into a five-step process which involves: Identifying customer requirements; Setting goals based on these requirements; Implementing strategies (both in terms of technical and management approaches with the systems/tools solutions) to satisfy these goals; Trending key performance indicators; and Benchmarking the results. When developing a maintenance management strategy, the first step is to identify the customer s needs. The next step is to develop a set of goals geared specifically to meet these requirements. At this point, the goals are still generic in nature, neither geared specifically to critical environments, nor to the day-to-day operational requirements of the facilities. However, these goals serve as the blueprint for all other planning requirements, both from a technical and management perspective. Without defining these goals at a high level, we cannot align our goals with the customer s. Once the blueprint has been developed and the direction and planning has been completed, the implementation stage of the process begins. The term resources includes the appropriate technical skills/tools, and the applicable management strategies associated with the technical strategies. Performance metrics provide the means for our management team and our customers to know if the action plans and management systems are working. The final step involves benchmarking operational data from one

57 37 project to another. CMMS gathers and normalizes data from each project which provides benchmarking information to compare each project s performance against the others, then electronically transfers it into International Performance Measurements (IPM) database. The internal and external information in these reports provide comparative milestones for use in tracking project cost and usage, in identifying improvements made, and (more importantly) in noting areas requiring improvement Maintenance Management Plan Maintenance has a specific mission. It must be viewed as the process that produces equipment reliability and system availability. The challenge is to produce these products in a timely and cost-effective manner that supports client objectives.

58 38 Figure 2.6 Maintenance Management Plan ( Source: Kurt Vonnegut, 1974) Figure 2.6, is the foundation of a well managed site and facility. The type and amount of information required to prepare an effective plan varies according to the type and size of the site or facility. Even the final plan is subject to revision over time to accommodate changes in circumstances, objectives, and goals. As important as it is to have a comprehensive, logically-based maintenance program, it is of little use unless the program creates value. The purpose of Maintenance Management Plan is to:

59 39 Align maintenance and operations with the customer s; business/mission/objectives for that facility; Establish standards that can be used to measure the progress of the site; and Implement programs to improve the performance and value of the facility Best Maintenance Practices No matter what type of organization is established, it must be flexible enough to accommodate the changing needs, responsibilities, and mission of the customer. Figure 2.7 shows the process to ensure the business and mission of the customer are met. Too rigid an organization results in a static situation, where innovation is minimized and maximum efficiency and dollar return are never realized. Figure 2.7 Best Maintenance Practice ( Source: Robinson, 1987)

60 40 Maintenance functions and processes must be standardized in order to accomplish objectives, carry out the plan, and allow people to work efficiently and effectively. The maintenance organization should not be a bureaucracy it should be understandable and a workable solution. This can only be accomplished with effective leadership. The Maintenance Management Plan includes a technical and management strategy for improving the reliability and availability of the facilities. The plan is designed to optimise reliability and availability while reducing costs and increasing profits, increase output without increasing unit costs, and increase customer satisfaction. This is handled by controlling the functions and processes. Continuous improvement plays a key role in our Maintenance Management Plan. By continuously improving maintenance functions and processes, will ensure our worldclass maintenance organization complies with its customer requirements Technical Strategy The first element of the overall Maintenance Management Plan involves deploying the strategic integration of the wide range of technical methodologies. The Technical Management Strategy, as shown in Figure 2.8, involves processes and control systems that ensure the reliability, availability, and performance of customer assets.

61 41 Figure 2.8 Technical Management ( Source: Wireman, 1991) The Technical Management Strategy utilizes processes proven through years of experience, coupled with existing maintenance improvement programs and new programs. The specific objectives of the Technical Management Strategy include: Ensuring equipment is maintained appropriately in a manner commensurate with its importance to safety, reliability, and availability; Optimising the number and performance of tasks and instructions (as identified through reliability modelling) to maintain an appropriate balance between cost and benefit;

62 42 Using operational histories and employing an effective logic scheme to determine the proper task frequency and text content to maximize equipment life-cycle; Establishing a documented technical basis for the task; and Maximizing the use of reliability-based technologies. By implementing a balanced proactive maintenance strategy based on Reliability-Centred Maintenance (RCM), Predictive Testing and Inspection (PT&I), Critical Environment Technologies (CET), and Critical Spare Parts, the merits of each level of maintenance (reactive, preventive, and predictive) combine to: Maximize equipment operability and efficiency; Minimize required maintenance time, materials, and, consequently, costs; and Minimize risk. Using RCM/PT&I allows quickly evaluating individual systems and identifying fault tolerant components that do not need maintenance. Maintenance resources are then applied to those critical systems and tasks affecting reliability and performance. Implementing our CMMS is important; RCM/PT&I programs cannot be effectively implemented without establishing equipment baseline characteristics and trending Probability of Failure

63 43 The development of new service technologies and maintenance management strategies have made it possible to determine the actual condition of equipment, rather than relying on estimates of when it might fail based on age or use. There are many different failure characteristics, only a few of which are actually age or use related. Recent research into equipment failure probability and advanced age has shown some surprising results. The most significant result is that there appears to be no significant link between age and the probability of equipment failure. The research also indicates, as shown in Figure 2.9, that there are six broad relationships, not just one or two. The first pattern, the well-known bathtub curve, begins with a high incidence of failure followed by a constant or gradual increase in the failure rate. The second pattern shows a constant or slowly increasing failure probability, ending in a wear-out zone. The third pattern shows a slowly increasing probability of failure, but does not identify a wear-outage. The fourth pattern shows a low probability of failure when the equipment is new or just out of the shop, then a rapid increase to a constant level. The fifth pattern shows a constant probability of failure at all ages (random failure). The sixth pattern starts with high infant mortality, but eventually drops to a constant or slow increasing failure probability.

64 44 Figure 2.9 Probability of Failure ( Source: Dean and Snell, 1991) The number and type of patterns seen varies from industry to industry. For example, the number of times these patterns occur in aircraft is not necessarily the same as an automotive plant. However, there is little doubt, as equipment grows more complex, more failures will follow the latter two patterns. Some important tips about how equipment should be maintained are as follow: Failure is not usually related directly to age or use; Failure is not easily predictable, so restorative or replacement maintenance based on time or use will not normally help to lessen the risk of failure; Major overhauls are not recommended, because of the increased probability of failure in the most dominant patterns; Age-related component replacements may be too costly for the same reason; and

65 45 Knowing the failure pattern does not necessarily tell you what maintenance tactic to use. From a probability failure standpoint, condition-based maintenance techniques are the most cost-effective System Bathtub Curve The bathtub curve is really a combination of two or more different failure patterns. One pattern embodies infant mortality, another indicates increasing probability of failure with age, and one (the central flat portion) suggests random failure between the two other patterns. This can be seen in Figure 2.10: System Bathtub Curve. Figure 2.10 System Bathtub Curve ( Source: Dean and Snell, 1991)

66 46 There are three stages of equipment failure: break-in stage, operating stage, and wear-out stage. During the break-in stage, the failure rate is relatively high. The failure rate decreases until it reaches its lowest point, where it can remain constant or vary to some degree for most of its operating life. During the operating stage, random failures or operational errors occur after the equipment has been in operation. Maintenance techniques used to avoid these types of failure are run-time preventive maintenance, predictive (condition) monitoring, and precision correction. Finally, the failures begin to increase again as the equipment starts to wear-out. As a piece of equipment nears the end of its life-cycle, failures often occur as part of the wear-out stage. By using predictive monitoring techniques, along with root-cause failure analysis and correction, most wear-out failures can be eliminated. The maintenance techniques recommended by this plan measurably extend the useful life of the equipment through reliability modelling Reliability Modelling One way to assess the overall effectiveness of a maintenance program is to track the Mean Time Between Failure (MTBF) of any asset. Taking this one step further, it provides the ability to assess the effective use of resources (i.e. labour, materials, and outsourced services) in the Mean Time To Repair (MTTR). There are three stages to the MTTR: response, stabilization, and restoration. These three stages compose total downtime - the total amount of time the asset is out of service due to failure, from the moment it fails until the moment it is fully operational. Response is the time from system failure notification to the acknowledgment of

67 47 response personnel at the failure location. Stabilization is the time it takes to mitigate the failure. Restoration is the time required to make the actual repairs. Stabilization and restoration can include the three levels of maintenance support to performs a failure analysis, including an evaluation of the downtime, to determine if any process improvements can be made to the MTTR. Figure 2.11 Reliability Modelling (Source: Pujadas and Chen, 1996) Two examples are shown in Figure 2.11 Reliability Modelling one shows a temperature scenario, the other shows a Heating, Ventilation, and Air Conditioning (HVAC) problem. Both examples have the three stages of MTTR associated with them. In the temperature example, the signature baseline becomes the basis for response to an operational problem. When the temperature reaches the upper control limit (UCL), an alarm sounds and a technician responds to the problem. During this stage, the system is stabilized (which may involve other factors besides repair such as switching power

68 48 over.) Once the system is stabilized, the technician restores the equipment to its original operating parameters. The key to the signature evaluation is that all of these events take place before a shutdown occurs. Periodic evaluations of signatures ensure system performance, thus increasing system availability. Corrective maintenance costs can reduce expenditures by as much as 70% from reactive maintenance costs. This can only be accomplished when accurate signature baselines are documented and then periodic signatures are derived from comparison against the baseline. In each situation, it is important to capture times for MTBF s and the three stages composing downtime or MTTR by equipment classification Management Strategy In addition to employing the technical methodologies previously described, the implementation stage of maintenance management strategy involves the deployment of a wide range of management activities requiring direction, planning, execution, analysis, and process interfaces. The Management Strategy is an effective, efficient management of resources, processes, and assets achieved by employing a standardized approach to maintenance management. This strategy is shown in Figure

69 49 Figure 2.12 Management Strategy ( Source: Robinson, 1987) The Management Strategy is a sound economic investment to minimize maintenance costs and resources through a standardized approach. This strategy involves: Developing the framework for quality maintenance processes to obtain availability and reliability; Defining logistic support for specific maintenance tasks; Meeting all regulatory requirements; and Achieving required and desired safety standards.

70 50 The primary objective of any effective maintenance program is to minimize total costs resulting from the execution (or lack of execution) of proper facility maintenance. Since these costs generally accrue in small increments through the performance of a number of small maintenance tasks, the ability to track each of these activities and their attendant costs is of great importance. Control is impossible without a sound management strategy. Without control, it is difficult to be aware of the need for changes in processes, procedures, or modifications to the current strategy. There are too many variables to expect a desired outcome without established processes and the accompanying controls. For management to accurately and effectively control the management function, the management strategy must include steps on systems reporting, communicating, and decision making. These steps can successfully be incorporated in the maintenance process by using a maintenance management system. CMMS is not simply an administrative management system it enables to maintain equipment histories, evaluate maintenance trends, perform cost/benefit analyses, and provide a wide range of other analytical functions. This allows to maintain of equipment to be more effective, i.e., through process interfaces. Table 2.1 illustrates a proactive role of the CMMS in maintenance and operations.

71 51 Table 2.1 Maintenance Management Systems Support Management Strategy Timely customer service and product delivery Expansion of market share Cost reduction Better use of resources Implementation of quality programs Integration of information for better planning and consistent decision making Improve product quality Improve safety and regulatory compliance Support from maintenance best processes Increases equipment utilization and equipment uptime Achieves greater asset utilization Achieves increased net capacity Increases production levels through increased equipment use, uptime, reliability, availability, and capacity documentation Reduces storeroom inventory levels and carrying costs Decreases cost to maintain equipment Increases craft labor productivity Increases equipment reliability, utilization, availability, and effectiveness Integration of maintenance management system into corporate methodology Provides activity-based costing of maintenance services Integration of maintenance operations with corporate quality systems Increases documentation of maintenance tasks related to safety and regulatory compliance issues

72 Maintenance Functional Mapping The organization structure should be comprehensive and cover strategic, procedural, technical, administrative, and cultural issues. While clear reporting relationships are administratively essential, getting products and services to customers requires an organizational structure that focuses on the nature and flow of work. To develop an effective organization that meets these needs, two things must be considered. The first need is to decide what work is to be done. The second need is to understand how work currently gets accomplished and to design the way it should be carried out. Form (structure) must follow function (processes). With this document plan, no attempt to define a maintenance organization structure is made have been tried. Tried to do is mandate the functions and processes required to provide the organization with the ability to increase equipment availability and reliability.

73 53 Figure 2.13 Maintenance Functional Mapping ( Source: Perrow, 1967 ) Table 2.2 shows the importance of the business strategy and the environment in which the maintenance function must perform. Table 2.2 Maintenance Management Systems Processes Direction Analyze facility s mission; identify, quantify, and document the need for maintenance Ensure facility is in best condition to support Execution Annual work plan to schedule work in a steady, efficient flow pattern

74 54 mission requirements Planning Maximize results from resources expended without waste Assess to determine effort needed to maintain facility at specified quality level Prioritize to determine needs and the order in which to meet them Adjust priorities and rearrange work flow patterns to accomplish special requirements Analysis Identify inefficiencies and methods to better execute maintenance Identify standards that are overly stringent for mission needs There is no correct organization structure that can be transferred from a book to a real-life situation. There are only strategies to be effectively applied to specific situations. Usually the best solution for an effective maintenance organization is a hybrid of centralized and local area functions. Centralized (Central shops for each trade or combinations of trades) Maintenance work is performed by individuals or groups dispatched from the central shops/labour pool. Maintenance work is assigned through the maintenance department. There are no trades assigned to specific operating or production areas. Communication is via formal planning and scheduling functions. Local Area (Maintenance trades are assigned to production or operational areas of the site) Work is assigned by supervisors or coordinators. Communication is through

75 55 a combination of formal planning, scheduling functions, and informal direct liaison. Specialized skills are provided by trades in the area. There is no centralized maintenance shop. Hybrid ( A combination of centralized and local area maintenance concepts) area crews are supported and supplemented by the central shop. Specialized skills are normally resident in the central shop Strategic Maintenance Tools Some buildings built 40 years ago were designed to last 20 years. However, due to changing circumstances, many of these buildings are still in use today. Properly maintained buildings are experiencing a lower dollar per square foot operating cost than comparable, poorly maintained buildings. In addition, if a building is sold, a wellmaintained building reduces the new owner s risk factor, thus enhancing the property s value. A successful maintenance program can pay considerable dividends to both the maintenance process and the facility fortunate enough to be taking full advantage of the program. The utilization of these tools as shown in Figure 2.14.

76 56 Figure 2.14 Strategic Maintenance Tools ( Source: Kurt Vonnegut, 1974) Figure 2.14, can result in fewer failures, more planned work, fewer emergencies, reduced overtime, extended equipment life, better use of personnel, improved equipment operations, less downtime, and reduced maintenance costs. 2.8 Batching Plant Equipment Maintenance A concrete mix is proportioned not only to meet the requirements of strength, durability, and workability, but also to produce a certain volume of concrete. The purpose of batching equipment is to meter the quantity of each material into the mixer so that the correct volume of concrete is produced.

77 57 Thorough mixing of concrete is accomplished when the materials are charged into the mixer at about the same time. This is possible because of the partial blending of materials, which occurs as they enter the mixer. Before the materials can be put into the mixer, each must be measured. This is accomplished by dropping material from the storage bin into a weighing hopper. Common hoppers, called cumulative batchers, batch by weight and are frequently used by ready mixed concrete producers for aggregates. Cement is normally weighed separately. These cumulative batchers weigh materials one after another in a common weight hopper suspended from a single weigh scale-lever system. Multiple batchers sizes range from one to ten cubic yards (0.8 to 7.6 m3) or more. They can be arranged to handle 2, 3, 4, or more different materials. Figure 2.15 Hoppers At Batching Plant. (Source: Landguth, 2002)

78 58 Figure 2.16 Conveyor Carrying Aggregate to Hopper (Source: Landguth, 2002) The batching plant must be on a level, solid base to prevent the twisting and binding of parts. This will cause problems with the scales, which in turn will not weigh correctly. Concrete footings make the best base. The contractor can use other bases as long as the plant is solid and remains level.

79 59 Figure 2.17 Diagram of Two Types of Hopper Systems (Source: NRMCA, 2002) Scales The scales are an important part of a batch plant. If they are not working properly, the following can occur: the volume cannot be controlled, moisture adjustments will be difficult, the slump could vary, or the strength could be low. The scale (380.3 B.1.) must be either a beam or a spring less dial type. The graduations on these scales cannot be larger than 0.1 % of the scales total capacity. For example, if the scale has a total capacity of 10,000 pounds (4,536 kg), the graduations cannot be larger than 10 pounds (4.536 kg) each. If the total capacity of the scale is 25,000 pounds (11,340 kg), the graduations can be as large as 25 pounds (11.34 kg).

80 60 Figure 2.18 Beam Scale (Source: NRMCA, 2002) Figure 2.19 Spring less Dial Type Scale (Source: NRMCA, 2002) The scales must be accurate to 1/2 (0.5) percent of the load being weighed. They must also be sensitive to a weight equal to one gradation of the scale. The scale is to see that they meet these requirements before producing concrete. The state scale inspector

81 61 checks the scales of most Ready-Mix plants annually. The scales will not need to be checked if they have a scale inspector's seal that is less than 1 year old and the plant has not moved since the seal was issued. If the plant does not have a recent seal or it has been moved, it must be checked. A beam scale must have an over-under indicator. This is another beam, but it shows a larger amount of movement than the main beam. The picture shows an indicator. It must have weight graduations up the side, which indicate how much the load is off if the pointer did not fall on zero. Figure 2.20 Over-Under Indicator (Source: NRMCA, 2002) There are times when weighing will be affected by wind. The wind pushing against the weigh hoppers could cause them to touch or bind. The wind may cause the hoppers to rock back and forth, causing vibrations in the lever arms. These vibrations cause the scale to bounce making it hard to weigh. Should wind cause such problems, have the contractor put up a shelter to protect the hoppers.

82 Water Meter Meters sometimes measure mixing water. These meters must measure water with a tolerance of ± 1 percent of the quantity. The insides of a meter are delicate. Long use, sand, or dirt can damage it causing incorrect readings. Water meter accuracy known by weighing the water pumped through it. If the water weighed is within ± 1 percent of the meter setting, the meter is acceptable for use. If the accuracy falls outside the ± 1 percent limit, make adjustments or draw an output curve. Some contractors have a Certificate of Calibration for their water meters. This can be used in place of actually checking the meter if: a. The meter is sealed; and b. The Certificate shows the serial number of the meter, date of calibration and states that the meter is accurate within a range of error of not over ± 1 %. This calibration will be considered good for a period of one year from date of calibration or until the meter seal is broken. This is because of a reason to suspect that the meter is no longer accurate.

83 63 Figure 2.21 Water Meter (Source: NRMCA, 2002) Aggregate Bins The plant must have separate bins for each size aggregate. The bins are filled from the top by conveyors. The plant has to be inspected so that material is not building up and spilling from one bin to another. The inside of the bins should also be inspected to ensure that there are no holes in the walls between the bins. Mixing the aggregates will result in failing test results as well as non-uniform concrete.

84 64 Figure 2.22 Aggregate Bin (Source: Skokie, 1979) Figure 2.23 Cross Section of Aggregate Bin (Skokie, 1979)

85 65 Figure 2.24 Cross Section of Aggregate Hoppers (Skokie, 1979) Drive-over receiving hoppers add versatility and capacity to the concrete batching plants, virtually eliminating the need for a front end loader. a. Up to 16 compartments; b. 10 tons (9 tonnes) to over tons (900 tonnes); c. Modular construction and assembly; and d. Heating system

86 Admixtures Each admixture should be added to the batch by a mechanical metering device. The device must be able to measure within + 3% of the net weight or volume per batch. The accuracy of meter is known by discharging a batch quantity into a container. Weigh (grams) the material to verify the + 3% accuracy. Most admixtures are specified in ounces and weighed in grams. Figure 2.25 Admixture Metering Device (The dosage of admixture) (Source: Landguth, 2002)

87 Automatic Controls A concrete paving batch plant must be operated with automatic controls. Batch plants for concrete masonry are not required to have automatic controls. The illustrations below depict what the controls do when separate scales weigh aggregates and cement. Open The Storage Bin Gates To Start Batching Close Gates When the Correct Amount Of Each Aggregate And Cement Is Weighed Out. Figure 2.26 The Automatic Controls (Source: Landguth, 2002) The automatic controls must also: a. Keep the storage bin gates closed when the weigh hopper gates are open; b. Must not open the weigh hopper gates when the aggregates weigh 2% more or less than they are supposed to weigh; and

88 68 c. Must not open the weigh hopper gates when the cement weighs 1% more or less than it is supposed to weigh. Figure 2.27 shows the two steps for an automation control to react when aggregates and cement are weighed on one scale: Open The Storage Bin Gate For the First Aggregate To Be Weighed Close The Storage Bin Gate When The Correct Amount Of Aggregate Has Been Weighed. Figure 2.27 Automatic Controls on When Aggregates and Cement are Weighed on One Scale (Source: Landguth, 2002) The two steps illustrated are repeated until the two sizes of aggregate and cement have been weighed. During that time the automatic controls must also: a. Keep the storage bin gates closed when the weigh hopper gates are open; b. Not open the next storage bin gate when the last aggregate weighed is more or less than the allowable tolerance. The allowable tolerance is ± 1/2% (0.5%) of the net weight of the total aggregate batch;

89 69 c. Not open the weigh hopper gates when the total weight of the aggregates is more or less than the net weight by 1/2% (0.5%) or more; and d. Not open the weigh hopper gates when the cement weighs more or less than the correct weight by 1% or more. The automatic controls need to be checked to make sure that they are working properly. The contractor is required to put less material in the weigh hopper than is allowed by the delivery tolerance. Then have him/her try to operate the automatic controls to see if the weigh hopper gates open (for aggregates weighed separately) or, see if the storage bin gates for the next size of aggregate open (when everything is weighed in one hopper). This procedure is repeated after putting more material in the weigh hopper than allowed by delivery tolerance. The same thing should be done with the cement weighing equipment. The plant should not start until these things are checked and the controls operate properly. If the automatic controls break down, the contractor is allowed to use the manual controls. Batchers must have the automatic controls fixed before work begins the next day.

90 70 Figure 2.28 Batching Control System (Source: Feng,2004) Figure 2.29 Main Screen Interface at Batching Control System (Source: Feng,2004) Cement Silos Cement Silos is an important part of the batching plant equipment whereby the cement to produce the ready mix concrete is stored at cement silos. There is a lot of type

91 71 and specifications of cement silos however the one shown in Figure 2.30 is the most common type. Figure 2.30 Cement Silos (Courtesy of I-mix Concrete Plant, Malaysia) The minimum specifications for a cement silos are: a. 50 tons (45 metric tonnes) to over 330 tons (300 metric tonnes) of storage capacity; b. 1, 2 or 3 compartments available; c. 210 ft² (19.5 m²) cloth area silo vent; d. Safety relief valve; e. Inside ladder;

92 72 f. Outside ladder with cage; g. Hand rails; h. High and low level indicators; i. Aeration system; j. Safety gate; and k. Inside cone coating. Figure 2.31 Cross Section of Cement Silos with all the Specifications (Source: Landguth, 2002) Aggregates Heating System

93 73 Hot Air Heating System for aggregates, which can reduce heating costs up to 50% due to the fact that the energy transfer is better and complete. It is simple and efficient. The gas furnace is connected to a fan with high static pressure. The air is heated by the furnace and then blown, by the fan, through diffusers installed at different levels inside the bin. The hot air will heat the sand and crushed stone at a predetermined degree and the thermo-switches installed in every bin compartment will send a signal to stop the heating in the individual compartments when it reaches the set degree Features of Aggregate Hot Air Heating System: Several features of an aggregate hot air heating system are as follows: a. Gas furnace; b. High efficiency industrial fan with high static pressure; c. Hot air ducts from heating unit to aggregate bin with motorized dampers for each compartment; d. Diffuser system; e. Thermo-switches; and f. Automatic control system.

94 74 Figure 2.32 Hot Air Heating System (Source: Landguth, 2002) Dust Collector Dust is picked up by enclosing the charging hopper as the truck mixer is being loaded. After loading, the shroud returns to its upper position, allowing drive-through operation. Operate the plant safely and cleanly in compliance with the strictest environmental safeguards.

95 75 Specifications for Dust Control are as follows: a cfm (8 500 m³ / hour) fan; b. Adjustable suction hood; c. Duct work from hood to fan; d. Flexible ducts; e. Pulse dust collector with hopper, manual gate and air dryer; and f. Retractable shroud. Figure 2.33 Dust Collector (Skokie, 1979) Delivery Fleet Maintenance

96 Mixer Maintenance A mixer must be kept clean and in good mechanical condition to do a good job of mixing. Accumulation of hardened concrete in the drum and mixing blades will reduce the efficiency of the mixer; therefore, concrete should be removed after each day s run. Badly worn mixer blades need to be replaced periodically. Each mixer has to be checked to see that the mixing blades are in good condition by crawling inside the drum. The manufacturer's manual should be obtained from the contractor for the correct blade dimensions. The contractor should replace the blades when they become worn down 3/4 inch (19.0 mm) or more. The sketches in Figure 2.34 below show different blades and where measurements should be taken. Figure 2.34 Mixing Blade Configurations (Source: NRMCA, 2002) Measurement of the blade should be taken at the point of the largest diameter of the drum. Blades worn more than allowed must be replaced before using the mixer. Quite often old dried concrete has built up around the blades. It should be removed before using the mixer or proper mixing of the concrete will not be achieved.

97 Truck Mixer Maintenance Figure 2.35 Truck Mixer and Transit Truck Mixer (Source: NRMCA, 2002) The truck mixers must be equipped with a revolution counter. It must be designed to count the revolutions of the drum when at mixing speed. It is recommended that the counter starts when the drum reaches the minimum speed.

98 78 Figure 2.36 Revolution Counter (Source: Landguth, 2002) The mixing time for truck mixers is 70 to 100 revolutions of the drum at mixing speed. Additional mixing beyond 100 revolutions must be made at agitation speed. If the counter fails to activate at mixing speed, ensure that the concrete is mixed for 70 revolutions at mixing speed before it leaves the plant. The range for agitation and mixing speed will often overlap. The contractor will normally use a drum speed within this overlap area so all revolutions are counted. This is acceptable, but the concrete mixes better if the drum turns at near maximum speed.

99 79 Truck Mixer Maintenance conditions are as per below: a. Internal condition hardened concrete build up; blade wear; b. Condition of charging and discharging openings, hopper and chute; c. Drum size conforms with rated capacity for mixing; d. Manufacturer s recommended mixing speed visible; capable of operating at mixing speed; e. Revolution counter functioning; and f. Accuracy of water gages, meters and pumps. Agitators Maintenance conditions are as per below: a. Internal condition hardened concrete build up; b. Condition of charging and discharging openings, hopper and chute; c. Drum size conforms with rated capacity for agitator; d. Manufacturer s max agitation speed visible; capable of operating at recommended speed; and e. Revolution counters functioning. Non-agitating Units Maintenance conditions are as per below:. a. Interior surface smooth, watertight, rounded corners; b. Gates or means to control concrete discharge; and c. Hardened concrete build-up; discharge of concrete not obstructed.

100 80 When concrete is supplied from a computerized concrete batch plant, continuous plant inspection is not necessary. A normal plant (scales, meters, admixtures, stockpiles, etc.) and truck (revolution counter, manufacture plate, blade wear, etc.) inspection shall be accomplished prior to the plant furnishing material to the project. The plant production and aggregate moisture determinations need to be reviewed with the plant operator. During the course of production, the plant and associated equipment shall be periodically inspected to assure that: a. The stockpiles are properly maintained; b. Material in bins is as indicated; c. The proper batch weights and aggregate weight are verified and have been corrected for aggregate moisture; d. Trucks are clean and empty prior to batching; e. Proper mix time or revolutions is being accomplished; f. Any new trucks are checked prior to use; and g. The rinsing of the truck mixing fins after batching is observed for excess usage of water. At the project site, the inspector should: a. Ensure that the appropriate information is on the ticket as specified; b. Ensure that the weight of material is within tolerance; c. Ensure that additional cement is added for small loads; d. Review time requirements;

101 81 e. Check to see if trucks are taking an excessive amount of time getting to the project; f. Check new trucks prior to use; g. Recommend mixing the truck load an additional 20 revolutions prior to discharge to assure uniformity of the mix; h. Recommend mixing the load an additional 30 revolutions after the addition of any water; i. Ensure the maximum allowable water is not exceeded; j. Check to ensure the aggregate moistures appears reasonable; k. Visually monitor the mix for slump or consistency changes. If the mix appears to have changed, obtain a sample and test the fresh concrete; and l. Take appropriate action based on the concrete test results. 2.9 Current Process involved in Operation at Ready Mix Concrete Production The Current Process involved in Operation at Ready Mix Concrete Production is as shown in Figure 2.37.

102 82

103 83 Figure 2.37 Concrete Production Process in Ready Mix Concrete Plant (Source: Brocklesby and Davison, 2000) Process Modelling Tool of Ready Mix Concrete Plant Petri Net Model The Petri net is a process-modelling tool for graphically representing the static processes and analysing the dynamic behaviour of a complex system (Mayer, 1992). The latest developments have empowered the Petri net with simulation capabilities to predict the final state of a system given changes in its internal and external conditions (German, 1995). According to Sawhney, 1999 highlighted the modelling procedures and advanced features of the Petri net for simulating construction processes, and developed a Petri net model for a RMC production system consisting of ordering, delivery, and storage of aggregates, cement, and sand, batching and loading of concrete, and travelling, unloading, and returning of truck mixers. Through experimenting with different configurations of plant resources on the Petri net model, the daily production rate of the plant was matched to the daily demand of sites for concrete (Sawhney, 1999). It is noteworthy that the Petri net model combined multiple sites into one queuing structure for unloading concrete on site, without considering the service levels achieved on individual sites in terms of timely delivery and truck mixer-hours provision and the effects of site-specific attributes on the activity duration such as the plant-to-site distance, the placing method. Hence, the Petri net model essentially addressed the one-plant-one-site RMC system, though the demand for concrete reflected the historical profile for multiple sites as modelled with an exponential distribution for generating site orders.

104 CYCLONE Model Cyclone was originally developed by Halpin in 1973 for simulating cyclic processes in construction and has been demonstrated as a simple and powerful tool for construction process planning in many applications. A CYCLONE simulation model integrating the concrete pumping operation with the batch plant operation was given in (Halpin and Riggs, 1992) for illustrating the dynamic generation of resource entities and interaction among various types of resources in CYCLONE. For example, truckloads of RMC were inserted into the site pumping process using a grouping of two QUEUE nodes one for truck mixer available, the other for the batch plant available and one COMBI node representing the batching process. A recent application extended the CYCLONE model in (Halpin and Riggs,1992) for simulating the operations of a RMC plant at West Lafayette, Indiana.(Zayed and Halpin, 2001). Key resources considered included truck mixers, pumping spaces on the site, and production facilities at the plant such as conveyor belts and hoppers for moving and storing sand and gravel. The CYCLONE model was utilized to derive several useful decision-support charts for the plant operator, depicting the complicated relationships between the resources available to the system, the productivity rate achieved i.e. the quantity of concrete placed in an hour, the unit cost of concrete i.e. total resources cost per unit of concrete produced, and the plant-to-site distance. For instance, optimum supply areas around the batch plant were defined in a form of contour line chart to help determine efficient resource configurations with minimum duration and cost for different distances. Nevertheless, as dictated by the actual operations of the plant being

105 85 studied, the CYCLONE model was only concerned with a one-plant-one-site RMC system, in which truck mixers of one single type and the pump placing method were employed. In addition, the Cyclone s limitation in defining resource entities did not allow for the flexibility of handling multiple types of truck mixers in the model One-Plant-Multi Site Model A study of the performance of Hong Kong s RMC plants showed that attaining a good match between the requirements of sites for concrete and the ability of the concrete industry to meet those requirements is paramount to one-plant-multisite RMC systems (Anson and Wang, 1998). Thus, in order to improve the match by simulating the RMC system, each site should be individually and explicitly dealt with. Given the possibly large number of sites a plant may serve, the approach of expanding the one-plant-one-site Petri net or CYCLONE model into a one-plant-multisite one is obviously unattractive. For instance, a CYCLONE prototype for handling two sites and single type truck mixers was constructed for illustrating the difficulty and inflexibility of such an approach and the bulkiness of the derived model (Ying, 2001). Resorting to other high-end simulation systems such as Visual SLAM (Prisker and O Reilly, 1999) would encounter similar barriers to modelling as with CYCLONE. It is noted that writing proprietary computer code or user inserts within a SLAM network model can produce compact representations of complex systems. However, from a practitioner s point of view, familiarization with specific terminology and the modelling schematics of particular software, as demanded for accurate simulation modelling, already presents a distinctive challenge for practitioners in construction, let alone the writing of computer code.

106 SDESA Modeling The cyclic process of RMC production and delivery between the plant and each site as illustrated in Figure 2.38 consists of six activities: a. Batching and loading concrete into the truck mixer at the plant engaging the batch bay; b. Washing and checking out the truck mixer at the plant not engaging the batch bay; c. The truck mixer travelling to a specified site; d. Unloading the truck mixer on site using a particular placing method engaging site crew and equipment; e. Washing out plus waiting on site not engaging site resources; and f. The truck mixer returning to the plant. Figure 2.38 SDESA model schematic for one-plant-multi site RMC system (Anson and Wang, 1998).

107 Schematic of Standard Ready Mix Concrete Plant Figure 2.39 Standard Ready Mix Concrete Plant (Source: Skokie, 1979) Powder Silo

108 88 Most concrete batching plants have one or more silos attached. Containing powder materials which can be injected into the mixer, this system provides a fast and easy way to operate Silo Pump Large pumps, based on the principle of Archimedes, "worms" so to speak, transport the materials contained in the storage silos up to the weighing unit Powder and/or Liquid Weigher Multiple weighing units to weigh water, cement, chalc etc. Raw materials, such as sand is weighed in the weigher / transporter, which load a given quantity of material on the skip. Below this unit is the mixer, where all the ingredients come together Mixer Several kinds of mixers possible: trough mixer, twin-shaft mixer and etc. The basic idea is the mixture of all the precisely weighed ingredients. The mixing process duration varies between approximately 15 and 90 seconds depending on the composition of the recipe.

109 Concrete Truck Mixer Various sorts of trucks, license plates, truck companies and other data can be entered into the database to gain the ultimate loading time of these vehicles Skip The skip provides a simple way to transport large amounts of raw materials to the weighing unit, on top of the mixer. Other possibilities, for example, is a conveyor Raw Material Storage To store the raw material for Ready Mix Concrete plant such as cement, aggregates and admixtures before the material transport to raw material weigher Raw Material Weigher & Transport Thorough mixing of concrete is accomplished when the materials are charged into the mixer at about the same time. This is possible because of the partial blending of materials, which occurs as they enter the mixer. Before the materials can be put into the mixer, each must be measured. This is accomplished by dropping material from the storage bin into a weighing hopper.

110 Control Room This is the place where our work is mainly done: a small cubicle where one or more computers monitor and control the entire plant. Recipes, error reports, actions, clients, transporters, readings and every other important parameter about the concrete plant can here be controlled, managed and viewed. Graphs and pictures enable a precise investigation of schedules, production and stocks. The main concept is : a database and an interface to control either the data stream and the plants processes Control Room Raw Material Storage Raw Material Weigher Skip Powder Silo Concrete Truck Mixer Mixer Powder and/or Liquid Weigher Silo Pump Figure 2.40 Schematic of Standard Process in Ready Mix Concrete Plant

111 Standard Maintenance for Ready Mix Concrete Production Facilities This is a maintenance checklist performed by a concrete plant inspector manually. This list does not contain all possible duties due to the differences in concrete plants, but it does contain the most important duties. The following items contain those things that must be completed prior to producing concrete: a. The standard specifications, supplemental specifications, special provisions, and plan notes that pertain to the project are on hand, are/have been reviewed and are correct for the project; b. The aggregate stockpiles are being properly built and are/have been checked for separation, segregation, and foreign material. Tracked loaders are not being used; c. The quality control tests for the aggregates, water, and admixtures are being performed or are on file; d. The design mix document is on hand; e. The plant is level on its foundation; f. The cement and aggregate scales are/have been checked for accuracy; seals and certificates sufficient for project duration are present; g. The water and admixture scales are/have been checked for accuracy; seals and certificates sufficient for project duration are present; h. The plant automatic controls and timer are/have been checked and are working properly; i. The mixer maximum volume and drum mixing speed have been checked and verified; j. The mixer blades have been checked against the manufacturer's diagram and are within wear tolerances; k. The revolution counters on the transit mix trucks have been checked and they work properly; and l. The site layout ensures a logical traffic pattern, safe operations, and proper drainage.

112 92 The following are items that must be in maintenance shortly after the start of production and performed until project completion. a. The required aggregate gradation tests are being conducted; b. Cement samples are being taken and sent to the Central Testing Laboratory; c. Certificates of Compliance are being obtained for the cement and admixtures, if required; d. Aggregate moisture tests are being taken and correctly documented; e. The batch weights are being adjusted for changes in volume, aggregate moisture content, sand F.M., workability, and water; f. Dirt balls and other foreign materials are being removed from the aggregate; g. The mixing time is being checked; h. Haul tickets are being issued when needed; i. Scales are being checked for balance and sensitivity; j. The hauling unit s cargo boxes are being checked for contamination; k. Cement checks are being made; l. Additional water samples are being taken when needed; m. The strength of the air-entraining agent is being checked so the proper amount is being used. Also, each air-entraining agent lot is being properly sampled; n. As necessary, the temperature required to heat water or the aggregates is being checked; and o. Safety is a daily critical inspection item.

113 CHAPTER III RESEARCH METHODOLOGY 3.1 Introduction There are two main aspects to the project; firstly, it is important to find the current maintenance of ready mix concrete production facilities at batching plant. These aspects should initially allow observation to provide a full understanding of the procedures and activities that involved in concrete batching plant. The factors that influence in concrete plant maintenance such as general operation, batching system, batching equipment, recording and delivery fleet maintenance and differences between CMMS at batching plant. Ready mix concrete production in concrete plant will also be observed on to extract raw data that can be later used as model input. Secondly, it is anticipated that it will be possible to develop a conceptual model for maintenance at ready mix concrete plant production facilities. This conceptual model will be basis to develop the CMMS maintenance software of the concrete batching plant. The analysed conceptual model will be used in two ways; to undertake parametric

114 92 experiments on the maintenance of the ready mix concrete plant facilities, and secondly to provide a tool for the estimation, planning and management of plant maintenance operation. The research project should follow a pre-determined plan if it is to run both effectively and efficiently. However research is a dynamic process, therefore there must be a certain amount of flexibility implying, although not requiring, that a contingency approach would be helpful. 3.2 Research Methodology The research study contained 6 steps and listed below in chronological order: 1. Literature review; 2. Data Collection; 3. Model Development; 4. Prototype Development; 5. Validation; and 6. Conclusion and recommendation Literature Review The aim of the literature review was to identify what various researchers have said on computerized maintenance management system, maintenance on concrete

115 93 batching plant equipment and modeling in concrete production process in order to identify the standard maintenance procedures in concrete batching plant. From the literature review, most information about the computerized maintenance management system at concrete batching plant is limited due to limitation of the scope of each study. Detail discussion on these studies is given in Chapter II Data Collection The process of collecting information from various sources is called data collection. The author has collected information for developing Computerized Maintenance Management Systems (CMMS) in batching plant from various sources like internet, articles, magazines, conference papers, reports and even opinions of experienced people in same specific fields. This research method was used for the purpose of data collection for this CMMS model development. Once the coding structure has been documented, data collection of all the master data of the modules to be implemented in the CMMS was commenced. The screens for these data are all available in the Masters module. Only data for the modules to be implemented were collected. Apart from the equipment maintenance data, other general ready mix concrete plant maintenance data was also be remedied during this time. Getting plant maintenance checklist data may easily be taken from the manual paper checklist but it

116 94 was decided that if each of the plant managers or expert be interviewed and asked for their data. This would allow for current data to be collected and also allow for discussions on the change of maintenance management such as process issues to take place. As and when the master data were collected, it was also keyed-in concurrently into the master module at CMMS model prototype Model Development Process Models Rapid Application Development (RAD) Modeling The systems Development Life Cycle (SDLC) is a framework for describing the phases involved in developing and maintaining information systems. Typical SDLC phases include planning, analysis, design, implementation, and support. There are few types of SDLC models; they are Waterfall Model, RAD Model, Prototyping Model, Incremental release Model, Spiral Model, V-model, B-Model and etc. Although there are many types of models, the author decides to use Rapid Application Development (RAD) Model as a research methodology. The choice of RAD Model as a research methodology is mainly because RAD is a methodology for compressing the analysis, design, build, and test phases into a series of short, iterative development cycles refer in Figure 3.1. This has a number of distinct advantages over the traditional sequential development model.

117 95 Figure 3.1 Rapid Application Development Model (Smith, 1999) Iteration allows for effectiveness and self-correction. Studies have shown that human beings almost never perform a complex task correctly the first time. However, people are extremely good at making an adequate beginning and then making many small refinements and improvements. We should encourage and exploit this rather than fight it. RAD projects are typically staffed with small integrated teams comprised of developers, end users, and IT technical resources. A small team, combined with short, iterative development cycles optimizes speed, unity of vision and purpose, effective informal communication and simple project management.

118 96 An important, fundamental principle of iterative development is that each iteration delivers a functional version of the final system. It is a properly engineered, fully working portion of the final system and is not the same as a prototype Dynamic Systems Development Method (DSDM) Modeling DSDM share a common approach to software development. Both method use iterative development and have a strong focus on developing software that meets the user s needs. Each process promotes a continual testing throughout the software development process, configuration management and prioritization of requirements. Core principles of DSDM are: a. After a feasibility and a business study, we run three independent cycling task forces are run: Functional model iteration; Design & build iteration; and Implementation. b. The business study produces a business area definition, a system architecture definition, and an outline prototyping plan: One of the cardinal aims is quick business benefit; The business environment is changing rapidly; Deployment of the system might be resisted; and Ownership by the users might be hard to establish.

119 Programming Language Visual Basic A programming language Visual Basic and environment developed by Microsoft was selected. Based on the BASIC language, Visual Basic was one of the first products to provide a graphical programming environment and a paint metaphor for developing user interfaces. Instead of worrying about syntax details, the Visual Basic programmer can add a substantial amount of code simply by dragging and dropping controls, such as buttons and dialog boxes, and then defining their appearance and behavior. Although not a true object-oriented programming language in the strictest sense, Visual Basic nevertheless has an object-oriented philosophy. It is sometimes called an event-driven language because each object can react to different events such as a mouse click. Since its launch in 1990, the Visual Basic approach has become the norm for programming languages. Now there are visual environments for many programming languages, including C, C++, Pascal, and Java. Visual Basic is sometimes called a Rapid Application Development (RAD) system because it enables programmers to quickly build prototype applications.

120 MS Access Microsoft Access is a relational database management system (DBMS). At the most basic level, a DBMS is a program that facilitates the storage and retrieval of structured information on a computer s hard drive. Microsoft generally likes to incorporate as many features as possible into its products. For example, the Access package contains the following elements: a. A relational database system that supports two industry standard query languages: Structured Query Language (SQL) and Query By Example (QBE); b. A full-featured procedural programming language essentially a subset of Visual Basic; c. A simplified procedural macro language unique to Access; d. A rapid application development environment complete with visual form and report development tools; e. A sprinkling of objected-oriented extensions; and, f. A various wizards and builders to make development easier. The advantages of using Microsoft Access are described as in below: a. A simple and cost effective RDBMS that is widely used and already in place in most maintenance operations; b. Can easily be upgrade to MS SQL Server; c. Can use VBA to program forms and reports.; d. Allows the application to be packaged as one rather than having different database and application connecting with each other;

121 99 e. Do not need a programmer to perform changes to user interface. Can easily be done by maintenance engineers. Also means it s not required to purchase programming IDE s like visual studio, Borland, etc.; f. Report writer is built in MS Access so no need to purchase external reports writers; g. Has built in wizards to help retrieve data to reports and forms so little code needs to be done; and h. Built-in tools for backup and replication Develop a Conceptual Modeling A conceptual model for computerized maintenance management system at concrete batching plant was developed based on data collection from concrete batching plant regarding concrete plant production facilities maintenance and process of concrete production at batching plant as per Figure This conceptual model was backbone to the model prototype which was developed from the context diagram and Data Flow Diagramme Develop Prototype Useful in "proof of concept" or situations where requirements and user's needs are unclear or poorly specified the approach is to construct a quick and dirty partial implementation of the system during or before the requirements phase. The prototype of maintenance software from conceptual modeling was developed based on the Data Flow Diagramme of concrete plant production facilities maintenance and process modeling, Rapid Application Development (RAD) and Dynamic Systems Development Method

122 100 (DSDM). Visual Basic and MS Access used as a language to programmed the prototype software Validation The next stage of any modeling process is validation. At this point any model that was not verified must be discarded or under go further amendments. The validation of a model is fundamental to the achievement of ones initial aims and objectives. If the model is not an accurate representation of the system being studied then any conclusions gained from the model cannot be relied upon. When carrying out the validation stage it will be useful to test several sets of input data and known outputs over a range of conditions including extremes. When more than one model is being used and has passed verification then it will be necessary to choose the most appropriate model. The prototype software was validated by the expert at the same field such as concrete plant manager to ensure the reliability and workability of the prototype maintenance software at batching plant. Since it is not advisable to run all the elements of CMMS at one go, small test runs by small locations had to be run first to ensure that everything is working.

123 Conclusion and Recommendation From all the results of the validation, the author was able to come to a conclusion and make the relevant recommendations.

124 CHAPTER IV CMMS CONCEPTUAL MODEL DEVELOPMENT ON READY MIX CONCRETE PLANT 4.1 Batching Control System in Ready Mix Concrete Plant The Figure 4.1 shows that data flow diagram for process at batching control system. Customer, normally the contractor at site will place the order to batcher who at ready mix concrete plant and batcher will received the order in form of amount of quantity and grade of concrete. Once the order received, the batcher will entered the order to the batch control system to process the concrete production. Before the concrete production, Computerized Maintenance Management System (CMMS) will do the preventative maintenance or act as a tool evaluation such as concrete batching plant equipment maintenance evaluation before concrete batching process. If it is good in terms of the production facilities maintenance at batching plant then it assigned to proceed with the concrete production. If it is bad then the work order will either discard or return to assigned to proceed with batching process. During the concrete batching process, CMMS will monitor the equipment to avoid breakdown or downtime. After the concrete batching process, the ready mix concrete will deliver to customer by concrete truck mixer to site. The information of batching process will export to ERP in

125 103 scheduling PC for continuous order in the future until the end of concreting activity at site. CMMS CMMS Figure 4.1 Data Flow Diagram in Batch Control System (Source: Larrard, 1997 ) Client s order from multi site will stored at batch server and batch historian will process graphic display, batch status and display alarms in touch with graphic development as per Figure 4.2. The printer will print the ticketing or delivery order for recording purpose.

126 104 Figure 4.2 Data Model Diagram of Overall Batching Control System (Courtesy of I-Mix Concrete Plant, Malaysia) The Figure 4.3 shows that the last link in the chain of devices required for batching is the means to control the batching devices. While some low-capacity products operate push-button controls that require visual observation of the scale display for batching accuracy, most plants use a form of electronic automatic batching control. It is virtually impossible to describe all the automatic batching controls available. They range from simple one-formula dedicated controls to computer controlled systems that include features that go far beyond the batching operation.

127 105 All automatic batching controls convert electrical signals from the dial scale, loads cell or volumetric pulse generators to weight values. These are then compared to the batch target values, and meeting the following conditions: a. The scale must be at zero before starting a batch.(the last batch must have been completely discharged); b. The charging device cannot be actuated if it is open; c. The discharging device cannot be actuated if the charging device is open; and d. The discharge device cannot be actuated until all the required materials batched and are within the applicable delivery tolerances. Today almost all automatic batching control use tare-compensated weighing where a cumulative weighing method is used. Tare-compensated weighing treats the weighing of each cumulatively weighed material as if it were being weighed in an individual batcher and then checks the delivery tolerance using the allowed values for an individual batcher. The old controversy as to the accuracy of individual batching versus cumulative batching is no longer valid since the same batching device is used in either case and the same tolerances are applied. For many controls, the batching is more efficient because pat experience has taught batcher designers and batching operators to automatically adjust for the amount of midair material and scale bounce, thus eliminating the need for manual control trim operations. Where these controls use a cathode-ray tube (CRT) to display batch operation, the target weights or volumes and the actual delivery values. In some cases, variations are displayed. Error messages pop up when needed and input instructions are displayed along with formula modifiers. With new batching control system with CMMS, recipes can be changed as often as desired and save your valuable time will be saved with every new batching process.

128 106 This existing batching control system can thus be integrated in CMMS model systems without any problems. Figure 4.3 Schematic for Process of Batch Control System to Batching System (Source: Larrard, 1997 ) 4.2 Ready Mix Concrete Batching Process Description The concrete batching and concrete product manufacturing activities may includes facilities primarily engaged in the mixing of cement and aggregate into

129 107 concrete, as well as concrete products, including aerated and concrete composite products. The term concrete refers to a product formed by two principal components: aggregate and slurry. Aggregate, which can be either natural or man-made, consists of various grades of sand, gravel, crushed stone, or slag. The slurry is composed of cement, water, and sometimes, entrained air. The cement slurry makes up approximately 25 to 40 percent by volume of concrete. Figure 4.4 shows the concrete batching processes with production facilities maintenance of Preventative Maintenance (PM) using CMMS model in ready mix concrete plant. As each production facility in RMC is likely to be unique it is advisable to develop a flow diagram that details the input of materials and prepare from the operation of each process. Figure 4.4 Concrete Batching Processes in Ready Mix Concrete Plant (Source: USEPA AP-42, 1995)

130 108 Concrete batching plants store, convey, measure, and discharge concrete constituents into concrete mixers for transport to the job site. The raw materials can be delivered to a batching plant by road or by rail, and are then transferred to elevated storage silos pneumatically, or by bucket elevator. The sand and coarse aggregate are transferred to elevated bins by front-end loader, clam-shell crane, belt conveyor, or bucket elevator. From the elevated bins, the constituents are fed by gravity, or screw conveyor, to weigh hoppers that combine the proper amounts of each material. The constituents are then fed from the weigh hopper to agitator trucks, where the concrete is mixed on the way to the site where it is to be used. Central mix facilities mix the concrete on site and then transfer it either to an open bed dump truck or a concrete mixer for transport to the job site. Shrink mixed concrete is partially mixed at the central mix plant, and then completely mixed in the concrete mixer on the way to the job site. For dry batching, where concrete is mixed and hauled to the construction site in dry form. 4.3 Integration of CMMS model in Ready Mix Concrete Plant Production Facilities Maintenance The Figure 4.5 shows that Computerized Maintenance Management System (CMMS) which is the core module to control an important three elements in the ready mix concrete plant production facilities maintenance as proposes by Wong (1999). Plant operations, management and instrument technicians are controlled by Computerized Maintenance Management System (CMMS) to enhance and optimized the plant maintenance.

131 109 Figure 4.5 CMMS Model in Ready Mix Concrete Plant Maintenance (Source: Wang, 1999)

132 CMMS Core Modules There are a few core modules that play an important role in developing CMMS modelling in ready mix concrete batching plant. Work orders contain information about a maintenance activity, such as where and how it is to be done, who is supposed to do it and any supplies needed to complete it. They keep track of maintenance activities and store valuable time and cost information that is used in reports. All tracked maintenance histories in ready mix concrete production facilities management system are based on the information stored in work order records. Creating work orders for all maintenance activities is the key to an efficient maintenance facility. Work orders can be uses to assign work quickly and in a format that helps improve the efficiency of facility. The machine and locations register is an essential module in CMMS model where all the batching equipment for production facilities will be given machine number for identification. Later, the location of machine and machine description are registered and machines are grouped together under a machine category. The current machine status describes which operational state the machine is in. A code assigned to a machine status and its description. This data is set in the masters. Machine or equipment and location require periodic maintenance to ensure uninterrupted efficiency and to guard against breakdowns. Preventive maintenance (PM) is a scheduled work on a machine. PM schedules can be planned for either a machine or physical location. Preventive Maintenance schedules requires 3 main components, the first one is the task list, steps that indicate what measures and work to be done on a particular machine or location. The second is the schedule itself, a time frequency of when the work should be done e.g. monthly, weekly, yearly and so on. The last component is the generation of the preventive schedule to a work order, so that the

133 111 technician can follow the steps on the schedule and track whether the preventive tasks have been completed. CMMS Machine Register Work Orders Preventive Maintenance Location Register Figure 4.6 CMMS Core Modules 4.5 CMMS Work Order of Functional Flow Diagram in Ready Mix Concrete Plant Work orders are written records of maintenance activities. They are used to assign maintenance to the areas and equipment that make up the maintenance facility. Work orders contain information about a maintenance activity, such as where and how it is to be done, who is supposed to do it and any supplies needed to complete it. They keep track of the maintenance activities and store valuable time and cost information that is used in reports. All tracked maintenance history in ready mix concrete plant

134 112 production facilities management system is based on the information stored in the work order records. As mentioned earlier creating work orders for all maintenance activities is the key to an efficient maintenance facility. Work Orders are created for a primary reason for regularly scheduled or preventive maintenance that is performed on a routine basis. Figure 4.7 Functional Flow Diagrams for Work Orders of Plant Maintenance in Ready Mix Concrete Plant (Source: Sivalingam, 1997)

135 CMMS Work Order Flow Diagram in Ready Mix Concrete Plant Production As Figure 4.8, work orders are written records of maintenance activities. They are used to assign maintenance to the areas and equipment that make up maintenance facility. The work order is raised when the plant equipment need to have preventive maintenance. The early stage of work order is to plan preventive schedule. In this case, planning to do maintenance is depends on the batching equipment or model in the batching plant. The pending production of concrete has to be notified since the production facilities equipment need to be shutdown for the maintenance. After notifying production on pending schedule, work order is generated. The work order complete with information in all aspects including job plan, specific equipment, tools and spares aspects create an effective plant maintenance compare to traditional plant manual checklist. After the maintenance work is done, the plant authority is informed to start operation of batching plant and close the work order. These life cycle procedures are carried out continuously in order to maintain ready mix concrete plant through efficient planning and scheduling. WORK ORDER Plan Preventive Schedule

136 114 Figure 4.8 Work Order Flow Diagrams for Plant Maintenance in Ready Mix Concrete Plant 4.7 Proposed Conceptual Model for Ready Mix Concrete Plant Production Facilities Management System The proposed conceptual model for ready mix concrete plant production facilities management system as shown in Figure 4.9 is divided into two main components, the first component is in ready mix concrete production and the second component is the plant production facility maintenance. The CMMS conceptual model

137 115 was developed based on ready mix concrete production and batching plant maintenance especially for batching equipment. During ready mix concrete production, CMMS will detect the problem or fault for preventive maintenance in batching plant production facilities. One of the elements in CMMS model will open for work request which is way plant maintenance personnel to aware and raise or highlight problems. It is a simplified Work Order screen for use by personnel who are not day to day users of the system. For any work to be carried out, a work order will be generated from the request module by authorised personnel. CMMS model will raised or generate the work order as per Figure 4.8 to plan preventive schedule. The work order will assign the work and build a job plan to proceed with preventive maintenance in batching plant production facilities. The actual maintenance job will be recorded for future maintenance reference. After the job maintenance plan accomplished, the work order will be closed. Basically, the proposed CMMS model will assist the production of ready mix concrete in batching plant by reducing the downtime or breakdown through early identification in batching plant maintenance work especially in plant production facilities such as batching equipment and batching control system. CMMS model helps ready mix concrete plant production facilities to save time and cost in maintenance work as well as to avoid the ripple effect due to concrete batching plant breakdown such as insufficient concrete supply to construction site.

138 116 Figure 4.9 Proposed Conceptual Model for Ready Mix Concrete Plant Production Facilities Management System

139 CHAPTER V READY MIX CONCRETE PLANT PRODUCTION FACILITIES MANAGEMENT SYSTEM PROTOTYPE DEVELOPMENT 5.1 Context Diagram This section introduces the context diagram, which represents the entire system of CMMS model for batching plant under investigation (refer to Figure 5.1). It also shows why this diagram should be drawn first, and then used to clarify and agree the scope of the investigation. Context diagrams are usually the first diagram to be produced and are often referred to as a level 0 diagrams. Only data flows to and from the system process are included in the context diagram. The figure shows that data flows to and from Ready Mix Concrete Plant Production Facilities Management System to batcher desktop.

140 118 Batcher Desktop User demand results Ready Mix Concrete Plant Production Facilities Management System Figure 5.1 Context Diagram for Ready Mix Concrete Plant Production Facilities Management System 5.2 Data Flow Diagram Level 1 This section introduces the level 1 diagram, which shows the main functional areas of the Ready Mix Concrete Plant Production Facilities Management System under investigation (refer to Figure 5.2). It explains why any system should only be represented by a single level 1 diagram. This diagram identifies the major functional processes of the system being investigated. The prototype of this data flow diagram level 1 known as a main menu shown as in below:

141 Login 2. Location Module 8. Exit Module 3. Work Order 4. Machine Module Ready Mix Concrete Plant Production Facilities Management System 7. Reports Module 5. Preventive maintenance Module 6. Masters Module Figure 5.2 Data Flow Diagram Level 1 for Main Menu in CMMS model The Main Menu of CMMS model Prototype has seven main modules or icons which are work orders, machine, location, preventive, masters, reports and exit (refer to Figure 5.3). The work order module provides with an ability to view and manage all maintenance activities. The work order module is integrated with the Planned Maintenance module in order to integrate scheduled preventive maintenance work with breakdown work. The Machine module provides with the facility to record and manage the production facilities equipment at batching plant. It stores data on every equipments which want a record of maintenance activities. The Location module provides with the facility to record and manage facility s location. It stores data on every location which

142 120 want a record of maintenance activities. This Preventive module describes how to schedule and generate preventive maintenance work orders within ready mix concrete plant production facilities management system. A preventive maintenance (PM) master and schedule specifies work to be performed based on an elapsed time interval or by metered / condition monitoring PM. PM schedules can be set-up for either a machine or a location. Masters module captures all your basic maintenance data which is required to start ready mix concrete plant production facilities management system. Report module provides a wide range of management reports. Reports are used for management information purpose, documentation and accounting of the productivity and performance of the maintenance departments. The Exit module is to close or exit from ready mix concrete plant production facilities management system prototype program.

143 121 Figure 5.3 Main Menu for Ready Mix Concrete Plant Production Facilities Management System Prototype as in Data Flow Diagram Level Data Flow Diagram Level 2: Login Process This section describes the subjective issue of deciding at what point a level 1 diagram contains sufficient detail. As a general rule no business process diagram should contain more than twelve processes, and those that are related can often be combined. Where external entities or data stores share the same origin or content, these can also be

144 122 combined in order to clarify the diagram. Where information is being retrieved from a data store, it is not necessary to show the selection criteria (or key), that is used to retrieve it. Furthermore, if the data is subsequently updated then only the update flow needs to be shown. Figure 5.4 below describes the login process to CMMS prototype model before access to the main menu of the prototype. The login form will be displayed to enter user ID and password for verification before user use the prototype. All the user ID and password will be stored in employee table database and retrieved back for valid user ID and password to access the main menu. If there were invalid user ID and password, then it will display login failed to exit module. This login process of prototype is shown in Figure 5.5 below. login command 1.1 Display login form User ID, password Invalid user 1.2 User verification Valid user User ID, password User ID, Password, Accessibility, Central, Auth, Exec Level 1.0 Employees table 1.3 Display login failed Exit command 1.4 Enable access to CMMS button Enter CMMS command, UserID, Accessibility, Central, Auth, ExecLevel 1.6 Exit 1.5 Display CMMS main menu Figure 5.4 Data Flow Diagram Level 2: Login Process

145 123 Figure 5.5 The Prototype Interface for Login Process Data Flow Diagram Level 2: Location Module The Data Flow Diagram (DFD) level 2 (location module) is depicted in Figure 5.6. The Line list provides the facility to record all the physical locations in the facility. This module stores data on every location with a record of maintenance activities. The components in display of Line List are display of current line, search, view all, new line and close the line list. Location can be organised by assigning codes. This would help the user to locate buildings, floors and rooms easily. User can also use location codes to raise service work order. Click on "Location" button on the main menu, a Location List will pop up. It will show a list of all the locations in the database. To add new location,

146 124 click on "New Location" button, a location screen will pop up. The following are a list of fields and explanations Location No, Description and Department. The following screens in Figure 5.7 are available in the Line list prototype. 2.0 department table DepartmentNo, DepartmentDescr iption 2.1 Display Line List Close command 2.6 Close 2.2 Display Current Line 1.0 location table LocationNo, LocationDe 2.3 Search LocationNo, LocationDescription, DeptNo, SiteCode 2.5 New Line 2.4 View All Figure 5.6 Data Flow Diagram Level 2: Location Module

147 125 Figure 5.7 The Prototype Interface for Line List in Location Module Data Flow Diagram Level 2: Work Order Module Work orders are written records of maintenance activities. They are used to assign maintenance to the areas and equipment that make up the maintenance facility. Work orders contain information about a maintenance activity, such as where and how it is to be done, who is supposed to do it and any supplies needed to complete it. DFD for work order module is shown in Figure 5.8. Display of work order list can be accessed from work order module. Display of work order list consist display of current work

148 126 order list, new work order, appointment list, print work order by batch, bypass list, view all, export to excel, search and work order close. Work type table, work status table, work trade table and work priority table will contain data for display in work order list together with work order table for information such as work order no., work type, work status, location no, problem description, requestor no, date received, employee no, work order trade, machine no, site code, date required, preventive maintenance target start date, as start date, downtime and work priority. The work order module prototype interface for data flow diagram level 2 is shown in Figure 5.9. WorkorderNo, WorkType, WorkStatus, LocationNo, ProblemDescription, RequestorNo, DateReceived, EmployeeNo, WOTrade, AssetNo, SiteCode, DateRequired, PMTarStartDate, AsstartDate, 1.0 work orders table 3.10 Close 3.1 Display Work Order n WorkStatusID, WorkStatus 3.0 work type table WorkTypeID, WorkTypeDescriptio 4.0 work status table WorkTradeID, WorkTrade 5.0 work trade table 3.9 Search 3.2 Display WorkPriorityID, WorkPriority 6.0 work priority table 3.7 View All 3.3 New Work 3.5 Print WO by Figure 5.8 Data Flow Diagram Level 2: Work Order Module

149 127 Figure 5.9 The Prototype Interface for Work Order List Data Flow Diagram Level 2: Machine Module The machine module provides the facility to record and manage an organizations machine in batching plant (refer to Figure 5.10). This module stores data on every batching equipment and machine which has a record of maintenance activities. The data flow diagram shows that inputs for display machine list are from machine table, machine status table and machine location table. The information such as batching equipment number, machine description, status, and location number and description are collected from these tables. A part that, the components for machine list interface for batching plant are display current batching machine, view all the batching equipment for

150 128 location and number, search for batching equipment number, machine description, status, location number and description, add in new equipment or machine, machine tree and close machine list display. The prototype interfaces for machine list are shown as in Figure machine status table Machine Status ID, Machine Status Desc 4.2 Display Current Machine Number, Machine Description, Status, 4.1 Display Machine List Location 2.0 location table Machine Number, Machine Description, Status, Location No, 1.0 Machine table 4.4 View All Location No, LocationDescripti on 4.7 Close 4.5 Search 4.6 Machine 4.3 New Machine Location No, Figure 5.10 Data Flow Diagram Level 2: Machine Module

151 129 Figure 5.11 The Prototype Interface for Machine List Data Flow Diagram Level 2: Preventive Maintenance Module Preventive Maintenance activities as shown in Figure 5.12 in ready mix concrete plant production facilities management system prototype can be scheduled either by fixed time intervals or by meters / condition monitoring. The following components are available in the preventive maintenance interface as per Figure 5.13: a. PM Task List Displays the PM Task List master. New PM Tasks can be added and existing PM Tasks can be viewed or modified in this section;

152 130 b. PM Schedule (Time) - Displays the master list of fixed time based PM Schedules. New PM schedules can be added or existing PM schedules can be viewed or modified in this section; c. PM Schedule (Meters) - Displays the master list of metered PM Schedules. Metered PM s can be scheduled either by incremental or threshold type meters. New PM schedules can be added or existing PM schedules can be viewed or modified in this section; d. PM Generation - Automatic generation of fixed time based PM Work Orders is accomplished via this screen; and e. Close Exits the menu. 5.2 PM Schedule 5.1 Display Preventive 5.6 Close 5.3 PM Schedule 5.4 PM Task List 5.5 PM Generation Figure 5.12 Data Flow Diagram Level 2: Preventive Maintenance Module

153 131 Figure 5.13 The Prototype Interface for Preventive Maintenance Data Flow Diagram Level 2: Masters Module The DFD for master module is as shown in Figure Frequently used codes and descriptions are recorded here for quick lookup by users. Updated during first time usage and later, on an as and when basis. The department section captures all the departments in the organization. The "Masters" interface in the main menu contains Department tab in the next level of data flow diagram. For Possible causes of equipment failure, user can also develop own coding system. Other than that, this section captures failure codes. The "Masters" in the main menu interfaces with failure code tab in the next data flow diagram level. Machine of similar functionality can be grouped together under a machine category. This enables easy management of asset data and retrieval. This section captures all the machine categories. The "Masters" in the main menu also interfaces with machine category tab. The suppliers and contractors component from the master list will captures all the suppliers or contractor who will involve in ready mix concrete plant maintenance. Apart that, miscellaneous (misc) component of the master list will contain work priority, work

154 132 status, work type, warranty contract, machine status and work type. This master contains default data for CMMS prototype to function. Users cannot delete the existing data but could add more to it. Data entered into this master will be saved upon exiting. The prototype interface for master list is as per Figure Department 6.7 Misc 6.2 Line 6.0 Display Masters List 6.3 Failure Code 6.4 Machine 6.5 Machines 6.6 Suppliers / Figure 5.14 Data Flow Diagram Level 2: Masters Module

155 133 Figure 5.15 The Prototype Interface for Master List Data Flow Diagram Level 2: Report Module Data entered into the system are retrievable in report format; depending on the type of reports the user needs (refer to Figure 5.16). This enables the user to analyze their data and prepare operational and management reports. For the data that has been entered, users are able to access reports for their operational needs. This report module provides a wide range of management reports. Reports produced by CMMS model is a combination of related data contained in the system. The reports are; machine list, machine details, supplier details, supplier list, work order list, work order details, department list, PM task list, PM Task checklist and physical location list. The prototype interface for report module is shown in Figure 5.17.

156 Close 7.0 Reports 7.1Preview 1.0 Report table Figure 5.16 Data Flow Diagram Level 2: Report Module

157 Figure 5.17 The Prototype Interface for Report Module. 135