Quality Management in the Design and Construction of Enclosure Systems. Mike Steffen Martin Houston Walsh Construction Co.

Transcription

1 Quality Management in the Design and Construction of Enclosure Systems Mike Steffen Martin Houston Walsh Construction Co. BEST3 Conference April 2012

2 Critical Barriers and Continuity Five critical barriers (control layers) of the hygrothermal enclosure Water-shedding surface Water-resistive barrier Air barrier Thermal barrier Vapor barrier Lack of continuity can lead to durability, comfort and/or energy performance problems in buildings

3 A QM Process within the Construction Industry Paper discusses quality management approach utilized by Walsh Construction Co. (WCC) Traces process by which continuity is established in design and then achieved during construction WCC PNW general contractor 350 staff, with annual billings of $ m Client base: non-profits, public housing agencies, educational institutions Mostly negotiated work, very little hard bid

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8 A QM Process within the Construction Industry By late 1990s, WCC experienced water intrusion leading to durability problems on several buildings Construction of very large wood frame buildings very common in PNW region esp. for MURBs and water intrusion problems discovered to be widespread by mid to late 1990s

9 A QM Process within the Construction Industry WCC initiated development of comprehensive quality management process in 1999 Initially intended to reduce water intrusion problems Has served as an important tool in delivery of high performance buildings The path was not clear at first

10 QM in Construction - A Unique Challenge Nearly every building is a prototype Unique site Unique program Particular climate Wide variety of systems used in today s buildings Project teams vary from project to project

11 QM in Construction - A Unique Challenge Price competitive procurement of goods and services is the norm within construction industry, leading to variation Eliminates one of key tools that could be used to improve quality: consistency of the vendor and supply chains for both design and construction Physical production environment Weather exposure Emerging trends Equity requirements

12 QM in Construction - Ordering the Chaos Resulting production environment chaotic (from S. Bertelsen, Complexity Construction in a New Perspective, 2003) How does one provide order to the chaos?

13 Add chaos image?

14 Quality Process during Design Design team takes lead the design quality process Overall responsibility lies with architect Contractor can play vital role, providing critical service and input: Cost Estimating / Budgeting Constructability Review Quality Concerns / Knowledge Perspective on what works well and what doesn t.

15 Cost Estimates / Budgeting for Quality Important that quality reviews are conducted concurrently with cost estimates so technical and process issues associated with costing are exposed and discussed Critically important to budget adequately for quality Avoid tendency to assume lower quality standard Problems result when budget is established based on poor early assumptions Early budgeting and estimates should be based on assumptions that are commensurate with owner expectations

16 Photo - Light Gauge Wall w Ext Insulation

17 Constructability Reviews Add significant value to the design process Brings field perspective to review of the design Experience with different materials, means & methods Experience with success and failure Open communication and collaborative questioning between design team and construction team Improves design & leverages improved construction documents

18 Tracing the Critical Barriers Constructability review should include analysis of critical barrier continuity Is continuity provided at each of the five critical barriers? Is this continuity clearly indicated in the design drawings Critical barrier review exercise: Trace each barrier through the building enclosure drawings Identify any discontinuities Thermal barrier continuity is best analyzed at wall sections and enlarged plan drawings Other barriers best analyzed at detail drawings

19 Source: NIBS Whole Building Design Guide

20 Source: NIBS Whole Building Design Guide

21 Communicating the Critical Barriers Contractor s review role is important to ensure requirements have been communicated effectively Without clear communication of requirements for quality (including continuity of the five critical barriers), the contractor and subcontractors involved in enclosure construction are likely to miss key necessary materials/components, or sequencing requirements, needed to achieve continuity of those barriers

22 Value Engineering - Impacts on Quality VE often devolves into cost-cutting exercises that reduce quality of end product All parties including contractor should reflect on fundamental purpose of VE and remain committed to this purpose as well as to the project goals Short-sighted decision making during VE can alter quality of end product in many cases to detriment of overall quality Consequences of changes in specs and detailing to reduce cost should be understood by all parties

23 Balancing Quality and Cost Some design team members tend to recommend only best / highest quality systems or products Service and value are provided when design professionals inform their clients of pros & cons of design options vs. alternatives proposed during VE System & material selection process is about finding the best balance of quality & cost with the many different systems & materials needed to create a building Typically best if everything gives a little

24 Quality Process during Construction Moving from design to construction, how does the contractor get it built right? Contractor leads the construction quality process Coordination of the Work Submittal Process Mockups Execution of the Work Testing / Coordination with BECx agent(s)

25 Schedule as a Quality Tool Proactive, effective planning is fundamental to producing quality results and a safe work site Construction phase schedule is the key tool used to plan and manage the Work Proper sequencing of the work of building enclosure trades must be considered and incorporated into schedule

26 Schedule as a Quality Tool The importance of the schedule cannot be underestimated! Four legs of the stool of project success: Safety Quality Schedule Budget Schedule is used to integrate the efforts and plans used to achieve the other three

27 Coordination, Coordination, Coordination General contractor fundamentally responsible for coordination between all building enclosure trades Scoping of work Sequencing of work Dimensional coordination Layout and control Compatibility of materials Submittals

28 Submittal Process Used to verify compliance with design specifications and drawings Materials and systems selected for desired level of quality and durability cannot be substituted Submittal process (including shop drawings) is primary vehicle for coordinating the Work Shop drawings used to verify that contractor understands the specific conditions and detail of the project Typical or standard details do not suffice

29 BEC (Building Enclosure Coordination) Meeting Best practice: GC should organize Building Enclosure Coordination Meeting early during construction phase Review, coordinate and verify issues related to the building enclosure Forum for addressing/expediting unresolved design issues Vital tool for improving submittal process Elevates attention of construction team members to building enclosure quality requirements Attendance required by all key subcontractors and architect, owner invited to attend as well

30 Building Enclosure Mockup Constructed soon after completion of BEC Meeting Serves as a tool to verify the enclosure design Serves as quality benchmark for the project Free standing mockup is preferable Detailing or material issues identified early on, before encountered on actual building Composed of as many typical detail conditions as possible Involvement of key personnel is essential Installing foreman for each enclosure trade should be assigned to work on mockup

31 QA/QC Testing Project quality will benefit from testing representative sample of installed product Ongoing testing during execution of the Work verifies quality of product received from manufacturers as well as quality of installation Clearly communicating the testing regimen to subcontractors informs them that at any time any installation may be tested for conformance Helps to ensure that subcontractors bring their best to the table

32 Enclosure Construction Supervision Continuous verification that execution is in accordance with design documents and manufacturer requirements is essential Installation crews can change, key personnel may not be available Material quality issues can arise Weather can impact installation quality Other human elements Consistent supervision of enclosure construction by qualified personnel is required

33 Enclosure Construction Supervision GC should assign specific personnel to quality control review of enclosure trade work Personnel trained in building enclosure design and construction principles Serves as eyes and ears of superintendent Specific focus on enclosure quality control Primary focus is to review, observe and document the installation of work, and oversee removal/ reinstallation of non-conforming work

34 The Value Proposition of Quality Costs: Focus on quality will increase costs in some areas Specialty position(s) in construction firm to manage quality? Increase risk associated with taking proactive position on design issues and concerns? Benefits: Reduced risk of failure of systems, components & materials Reduction in warranty costs Insurance cost reduction? Synergistic impacts on safety, schedule & budget performance

35 The Value Proposition of Quality Producing quality, durable work is a hallmark of many construction firms Investment in QM provides substantive payback in maintaining reputation over time Reputation for delivering quality buildings on consistent basis helps to secure future work in highly competitive construction marketplace

36 Questions?

37 Thank You

38 Coordination Case Study 38

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40 Source: Ankrom Moisan

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