Measure Twice, Cut Once
Barber
Mechanical and electrical systems in school buildings are becoming more complex, requiring a higher level of coordination among facilities and systems to ensure proper integration. Kent Barber, managing principal of Keithly Barber Associates, of Burien , Wash. , discusses the importance of commissioning — when planning a new school building or renovating an existing one — to ensure that buildings and their systems perform correctly.
With 30 years of experience in construction, design, engineering and optimizing existing systems performance, Barber answers questions from readers and School Construction News about why commissioning is necessary, how and when to start the commissioning process and some of the challenges that architects, engineers and commissioning agents face.
Q: Why do I need commissioning? Aren’t the engineers and builders bound by contract and specification supposed to make sure everything is designed and installed to work properly?
A: This question has been discussed as long as we have been discussing building commissioning. A practical way of answering this question is to ask, “Do your new buildings function in accordance with your expectations?” If you answer yes, then you don’t need commissioning. If you (like most owners) answer no, that is why you need commissioning.
It’s harder to explain why commissioning plays such a significant role in obtaining acceptable functionality. Two frequently discussed factors are the increasing sophistication and complexity of building systems, and the inherently fragmented nature in which we often design and build our buildings.
In an effort to optimize building comfort and efficiency, our mechanical and electrical systems are becoming more sophisticated and complex. As a result, it is becoming more difficult to coordinate the interaction of these specialized systems and disciplines.
At the same time, designer scopes of work may be tightly defined in an effort to control costs. The commissioning agent can provide big picture continuity throughout the project, which otherwise may be absent for the mechanical and electrical systems.
Q: My district recently got a referendum approved to start a five-year capital improvement plan, which will include both new construction and renovations. The design process has not actually started yet. When should we bring on a third-party commissioning agent and how long should we retain them?
A: There are significant advantages to making the third-party commissioning agent a part of the project team early in the design phase — even pre-design for some projects. Commissioning is most effective when it is an integral part of the overall design/construction process. This is best accomplished by forging a strong team that is committed to commissioning early in the design phase. A cooperative construction phase commissioning team follows with the support of understandable, biddable and enforceable commissioning specifications.
Beginning the commissioning process early also facilitates cost-effective development of three valuable commissioning- related tools — the Owner’s Project Requirements, the architect/engineering team’s Basis of Design, and the Systems Operation Manual.
How long to retain your agent also varies with the project and the facility’s requirements. Some commissioning guidelines suggest the agent provide a post-occupancy review, in which the agent reviews building operation with operations and maintenance staff and occupants approximately 10 months after substantial completion.
The agent can also provide training for the operating staff on the systems operation manual, and on the capabilities of the systems to the occupants.
Another factor to consider when planning to start and stop commissioning is whether or not your project will participate in one of the sustainable, high performance building programs. For the U.S. Green Building Council LEED program, you obtain credit by having the agent do a design review and a post-occupancy commissioning review. This, of course, requires involving the agent from no later than mid-design through post-occupancy.
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Q: My school district wants to implement several green retrofitting projects within the next 12 to 18 months. I’d like to get at least two staff members certified for commissioning to help with these projects. What kinds of commissioning certification programs are available and how long does the process take? Will my staff members’ credentials be recognized by accreditation organizations?
A: Before I answer this, I should also disclose that while I’ve been a dedicated commissioning professional for more than 15 years, I am not certified as a commissioning agent by any organization. I caution owners against believing that they can rely on certification in lieu of going to the trouble to check with other commissioning consumers about the performance of potential agents.
I personally don’t believe that commissioning certification is particularly valuable, and while a number of well- known top-notch commissioning professionals agree with me, there are highly regarded commissioning professionals and stakeholders who strongly disagree.
I am aware of five different commissioning agent certification programs. These programs are offered by the AABC Commissioning Group, which is a part of the Associated Air Balancer Council; the Building Commissioning Association; the National Environmental Balancing Bureau; the Sheet Metal and Air Conditioning Contractors’ National Association; and the University of Wisconsin , Madison . There has also been considerable talk about ASHRAE offering commissioning-agent certification in the future.
These five existing programs have somewhat different emphases, and none of them is widely recognized as the standout or leader. The programs I am most familiar with require applicants to document some level of commissioning or commissioning-related experience before they can sit for an exam, which must be passed. Training courses from the certifying organizations are available, ranging from part of a day to several days in length. To my knowledge, the University of Wisconsin , Madison ‘s commissioning training program is the most comprehensive of these. I know commissioning professionals and facilities people who feel they benefited significantly from taking the university’s commissioning courses.
Q: Despite initial training, my maintenance staff is complaining that the automated HVAC controls at our two new schools are too complex to use. As a result, the system is not being operated properly and not running at peak efficiency. There are high expectations for these new integrated, energy-efficient systems. What’s the best way to handle this?
A: This is a very important topic. The current emphasis on energy efficiency and green design can direct new projects toward more complex HVAC systems and control logic. These systems may have the potential to provide great comfort and energy efficiency. That potential will not be realized during the building’s life, however, if the demands of the systems exceed the resources of the operating staff. Three commissioning-related documents — the Owner’s Project Requirements, the Basis of Design and the Systems Operation Manual — directly address this and can be cost-effective keys to successfully commissioning and sustaining building functionality.
• Owner’s Project Requirements: the OPR describes the owner’s functional requirements for the project, including priorities and how successful implementation of these requirements will be determined, i.e., the success criteria. This document embodies the criteria by which the success of the project will be judged relative to meeting the owner’s needs. It is a living document. As questions arise during design, the OPR is looked to for the answer. If the answer is not in the OPR it may be necessary to modify the document in order to document the answer.
• Basis of Design:
The design team develops the BOD documentation from the OPR. The BOD documentation is an opportunity for the design team to verify its understanding of the OPR and describe how it intends to achieve its goals. The BOD records the concepts, design assumptions, important calculations, decisions, product selections and rationale used to satisfy the OPR, regulatory requirements, and industry standards and guidelines.
Updated editions of the BOD document are required as a part of each design submittal. The commissioning agent reviews the OPR, BOD and the plans and specs for consistency.
One of the most important issues to be addressed in the OPR and BOD is how the systems comply with the requirements and resources of the operating staff. Successful long-term system performance demands that the complexity of the systems, and amount of maintenance they require, be well matched to the capabilities of the operating staff.
• Systems Operation Manual: The SOM is provided by the commissioning agent at the end of project commissioning. The SOM differs from traditional operation and maintenance manuals — which focus on equipment maintenance — by addressing the operating characteristics of the overall systems, including interaction between systems. The document is intended to assist facilities and operating staff, as well as future designers of revisions, retrofits and remodels.
These three documents may be developed as a part of the overall project process with little to no additional project cost. After the owner takes over the building, the documents will provide information regarding design intent, basis of design and functionality for the life-long operation and evolution of the building.
Q: What are the most common problems that you have encountered when it comes to ensuring that building systems are designed, installed, functionally tested, and capable of being operated and maintained according to the owner’s operational needs?
A: Two recurring problems stand out for me. The first is more of a challenge than a problem and it is not technical in nature. The biggest challenge is getting the project team to take a true team approach to the collective ownership of the project’s functional performance. As a result, team building and leadership are paramount commissioning agent skills. Without them an owner is as likely to get a lengthy list of unresolved issues as they are to get a building that works.
The other challenge is the lack of understanding about how components and systems work together to achieve the desired control strategies. Building commissioning has demonstrated that clearly understanding and documenting control logic and control systems integration early in the project addresses important issues that otherwise become costly to resolve during functional testing.
At a minimum, control logic and integration need to be well understood and documented before control programming begins and before functional testing procedures are written. By working as a team, the design engineer and the commissioning agent can perform a process during design that allows control logic and integration issues between equipment, systems and disciplines to be resolved so that procedures and responsibilities are clearly specified. This allows pre-functional testing checklists and the commissioning functional performance tests to be clearly specified in the project bid documents, making the construction phase commissioning process more biddable and enforceable.