Building Commissioning: The Key to Buildings That Work
Complex buildings require careful testing to ensure they work as intended
In the not-so-distant past, buildings were simpler than they are now, and the roles of building professionals were less specialized and fragmented. Architects could effectively oversee the construction process, and contractors understood all the systems they were installing. Buildings were expected to provide basic shelter. If they had comfort-control systems, a relatively wide margin of indoor conditions was generally tolerated.
Today all that has changed, especially in larger commercial and institutional buildings. The buildings contain many sophisticated systems for controlling comfort conditions and lighting, moving people and equipment, providing security from intruders, and enhancing occupant safety. Building envelope and structural systems are also more complex, with engineered membranes and coatings, selective-surface glazings, and other features.
Designing and installing these systems requires specialists who may have only a limited understanding about how each system affects other aspects of the building. Furthermore, these specialists are often discouraged by tight budgets and liability concerns from asking questions about components that are not within their strict areas of responsibility. Amazing as it may sound, it is not unusual for large and very expensive buildings to be built without any one party having overall responsibility for ensuring that the systems all work properly. Enter building commissioning.
What Is Commissioning?
According to the Building Commissioning Association: “The basic purpose of building commissioning is to provide documented confirmation that building systems function in compliance with criteria set forth in the Project Documents to satisfy the owner’s operational needs.” In simpler terms, commissioning involves a party—other than the designer or contractor—who is charged with ensuring that a completed building meets the design intent and requirements of the owner.
The practice originated, as the term suggests, as a more comprehensive version of standard mechanical system
testing, adjusting, and balancing (TAB). Over the last decade the role of commissioning, at least as defined by its proponents and practitioners, has expanded in several ways. Originally involving only the heating, ventilation and air conditioning (HVAC) system, commissioning expanded first to include other automated building systems such as lighting, security, and fire-safety. Now the concept of “total building commissioning” has emerged to include the functional aspects of all building components, including structure, shell, and finishes.
The preferred role of the commissioning agent now begins much earlier in the design and construction process, with the goal of catching potential problems before they are built. Most commissioning agents now expect to review construction documents and any change-orders and submittals from contractors that affect the systems being commissioned. Construction documents are typically reviewed just before they go out to bid, although many commissioning agents prefer to review the design much earlier. Some even suggest that they can play a valuable role during the programming stage by helping to clarify and document the owner’s needs and goals for the design. At a minimum, they argue, the commissioning agent should be included before design is under way to establish, in the design and construction contracts, their role in the process.
At the conclusion of construction a commissioning agent not only tests all the systems but also provides a final report that organizes for the owner many important details about operational guidelines and maintenance requirements.
Often the commissioning agent will continue to monitor the building for its first year or two of operation, helping to ensure that operations and maintenance (O&M) procedures do not undermine system performance, and helping to resolve problems that arise. Ultimately, the commissioning agent can serve as an owner’s representative from the earliest stages of the process through initial occupancy, helping to define design goals and performance criteria, and then monitoring to see that those goals are honored throughout the process.
Commissioning of existing buildings is also feasible, although it is, of course, limited to testing and inspecting what already exists. Existing buildings are usually more difficult to commission because systems evolve over time in complex—and usually undocumented—ways.
Architectural engineer Walter Grondzik of the University of Oregon suggests that, fundamentally, commissioning involves three tasks:
1. Documentation of design intent;
2. Field-testing of systems and equipment; and
3.Transfer of O&M requirements and supporting documents to building management.
Grondzik adds, however, that commissioning “best practices” go beyond these basics to include peer review of design decisions during the design process and training of building management, among other tasks.
Building professionals in the United Kingdom have performed what they call “commissioning” since the 1970s, according to Chris Parloe of the Building Services Research and Information Association. For the most part, however, this practice is closer to what American engineers call “TAB.” The British use the term “commissioning management” to describe the more comprehensive services that might extend throughout the design, construction, and occupancy process.
When learning of commissioning for the first time, many people question whether yet another professional service is really needed in the building procurement process. After all, aren’t the architects and engineers hired to translate the owner’s needs into a design that works and then to oversee the construction to ensure that it does? And if the mechanical system specifications call for TAB, won’t that ensure that the systems are working?
“The construction industry just doesn’t have the resources to deal with the complexities of modern buildings,” says J. David Odom, vice president of the Building Services Group at CH2M HILL. “I have yet to see a significant building failure that building commissioning wouldn’t have prevented, and I can say that after seeing several hundred problem buildings.”
While there is a tendency to assume that the design is sound and that problems occur during construction, this is not necessarily the case. “Problems occur either in the design, or in installation, or in maintenance,” notes Joy Altwies of Dorgan Associates, a leading commissioning provider. In a paper presented at the 7th National Conference on Building Commissioning, held during May 1999 in Portland, Oregon, Mike Kaplan, P.E., of Kaplan Engineering is more specific, reporting that between 15% and 33% of deficiencies he has encountered during commissioning are attributable, at least in part, to the designers.
Grondzik argues that architecture and engineering fees have become so tight, and contracts so narrowly defined, that designers cannot be expected to ensure that their systems are constructed to work as designed. In lieu of actually overseeing the construction process, “engineers have observation rights at best,” Grondzik notes. From this perspective, commissioning aims to provide a service of project monitoring and troubleshooting that architects and engineers no longer have the resources to provide.
Even within the more narrow realm of post-construction commissioning of HVAC systems, there is still a substantial difference between conventional TAB and commissioning. “TAB is the setup and adjustment of air and water flows in the HVAC system,” says Karl Stum of Portland Energy Conservation, Inc. (PECI), a leading commissioning advocacy group. In spite of the terminology, “TAB isn’t really testing,” Stum continues. He notes that during TAB the engineers may discover problems with the system simply because they are the first ones who try to use it, but that they are not expected to do comprehensive tests of the system, much less to measure its performance against original design intent.
Commissioning can be seen as a quality check to reduce costs and delays associated with contractor requests for information, change-orders, and call-backs due to building performance and comfort problems, or as an insurance policy against more serious building failures. Either way, advocates argue, the earlier commissioning agents are involved in the process, the lower the cost of addressing problems they uncover. Perhaps more important, involving the commissioning agent early allows them to work collaboratively with the designers to minimize problems and avoid the potential for conflict and finger-pointing if problems are discovered when they are expensive to fix.
As a new service in a conservative industry, commissioning can be a hard sell to developers and owners who have to pay the bills—at least until they’ve experienced the benefits. “Owners considering commissioning for the first time have more of a show-me attitude,” says Stum, adding, “Any owner who has done commissioning at some point during the construction phase will say: ‘Next time we want to start sooner.’” Among these convinced owners is the U.S. federal government: President Clinton’s Executive Order 12902 of March 8, 1994 requires that federal facilities be commissioned to ensure that they meet energy efficiency and water conservation guidelines of that Order. That same order also directs the Department of Energy and the General Services Administration (GSA) to develop a model commissioning program, which has led to the development of a
Building Commissioning Guide from those agencies.
What Does It Cost?
The cost of building commissioning varies greatly depending on the scope and duration of services, complexity of the building, and nature of the contractual relationships (see table). For a thorough commissioning service, Altwies estimates a cost of 2% to 3% of the cost of the systems being commissioned.
These figures include paying for the additional work required of designers and contractors to make commissioning work.
Since the commissioning agent is charged with reviewing the work of others and ensuring that systems work together, cooperation from the designer, contractor, and building manager is essential. In fact, the commissioning team for a large project will typically include representatives from each of these organizations who must be paid for their time in meetings, consultations, and preparing documents for review. Clients have found that even with design-build projects, which include standard levels of quality control, requiring (and paying for!) a separate commissioning process is important to ensuring a trouble-free building. “When commissioning goes well,” Grondzik notes, “you are getting deeper checks and more detailed documentation. Even if nothing is found, the documentation alone is worth the fees.”
The justification for this extra expenditure, according to Altwies, is that commissioning always pays for itself in avoided back-and-forth with designers during construction, contractor callbacks, occupant complaints, and building performance. Odom describes a $100 million project for the State of Louisiana in which the project manager was convinced by the design team to involve a commissioning agent late in the process. It cost $120,000 for a thorough design review by commissioning agents just before the project went out to bid, but value engineering opportunities were revealed and constructability problems were avoided, saving well over $5 million. Although there was no budget for commissioning, the owner had set aside 6% of the project cost ($6 million) for contractor-initiated change-orders. Much of that money was saved by the commissioning process, even though it took place so late in the design phase.
By way of contrast, a $40 million U.S. Army project—a 12-story addition to a four-star hotel on Waikiki Beach in Honolulu—was not commissioned until problems emerged after construction. The problems, which resulted in comfort complaints, moisture and mildew problems, and material degradation, cost $6.5 million to rectify, according to CH2M HILL. Had the building been commissioned before construction, these problems could have been avoided.
Good designers and contractors know that any type of building can benefit from good engineering and great attention to details, but are there certain situations in which the extra rigor of a thorough commissioning process is especially appropriate? Very large and complex buildings are obvious candidates, but there are other “warning factors that make commissioning a high priority,” according to Odom.
At the top of Odom’s list are buildings in which mechanical equipment is serving especially large loads, such as laboratories with very high ventilation requirements. Another example Odom cites is buildings in which occupancy levels vary dramatically, such as courthouses. Finally, climate can be an important factor— buildings in hot-humid climates and in very cold climates are more susceptible to problems. Failing to commission simpler buildings may result in comfort problems and excessive energy use, but failing to commission these high-risk buildings, according to Odom, can lead to catastrophic building failures.
Even within complex buildings, if commissioning is done at all, it most often addresses just the mechanical systems and building controls. When resources for commissioning are limited, Grondzik suggests that a facility manager focus first on those systems that have historically been the most troublesome: “Ask what causes problems for maintenance and operations people today in their existing facilities, and commission those systems,” he advises.
Architects and Commissioning
Commissioning is a hot topic among engineers, construction managers, and facility managers, and it is well represented at their conferences and in the trade press. Architects, however, if they are aware of commissioning at all, still typically perceive it as an enhanced form of mechanical system TAB and entirely within the engineer’s realm. The concept of total building commissioning is foreign to most architects. Judging by the complete lack of sessions on the topic at The American Institute of Architects’ Convention 2000, architects are likely to remain in the dark about it for the near future. “The architectural community is missing an opportunity here,” says Odom.
When faced with the prospect of a commissioning agent participating in a design process, the architects’ response ranges from very positive to very reluctant, according to Grondzik. Some firms welcome an outside perspective on their design choices, while others view it as an unwelcome intrusion into their process.
While commissioning can play a role in reducing the risk of serious building failures, it is also valuable for the less dramatic role of ensuring that targets for comfort, energy use, and water use are met, both in design and in the actual building. It is this more mundane role, in fact, that spurred substantial growth in the commissioning field during the 1990s, as utility companies—especially in the Pacific Northwest—began sponsoring the commissioning of projects to increase real energy savings.
The U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) rating system recognizes this value. The proposed version 2.0 of LEED includes a basic level of commissioning as a prerequisite for any rating, and a more advanced level as an option for additional credit. Canada’s C-2000 for advanced commercial buildings also promotes commissioning. Even the Canadian R-2000 program for residential buildings has just adopted a new “commissioning” requirement, although in practice it only amounts to a TAB process for houses.
Some commissioning agents have noted that total building commissioning is highly compatible with the role of “sustainability coordinator” for green projects. In the February 2000 issue of
Heating, Piping and Air Conditioning, Stum proposes that a commissioning agent can help to monitor a design and document compliance with the requirements of a green rating system. Whether it is in the context of a formal rating, or simply to meet an owner’s green goals, a commissioning agent with expertise in green approaches and technologies is in an excellent position to check for conformance to those goals at various stages of design and construction. This might include commenting on proposed products and systems during design, reviewing specifications to see that the chosen systems are properly documented, reviewing contractor submittals to ensure that any substitutions still meet the green requirements, and checking installations during and after construction. While commissioning of mechanical systems is useful even after construction, when it comes to static building elements such as structure and finishes, reviewing them during design is essential, notes Stum.
The practice of commissioning has changed and evolved rapidly through the 1990s, and no one suggests that it has yet found a final form. “We keep trying to find ways to make it faster, more efficient, cheaper for the owner,” says Altwies. “We found that the checklist formats that were widely accepted a few years ago were driving project costs up too much. The way we’re doing things is constantly changing and improving.” One likely evolution is increased use of sophisticated computer modeling to describe the conditions that equipment and systems
should be creating, which then simplifies on-site verification efforts. Researchers at Lawrence Berkeley National Laboratory are currently testing a prototype of one such tool, which they call the Information Monitoring and Diagnostic System.
Odom concurs that cost has been an issue, not only in terms of the cost of the commissioning process itself but also in terms of the proposed changes that result from the project. “The problem with having it as a purely independent discipline is that the agent can make recommendations without justifying their effects on the project budget and schedule,” he notes. Partly in response to this concern, the GSA has started bundling commissioning into contracts for construction management services. This approach “puts a business context onto commissioning,” Odom suggests.
A Guideline Project Committee under Technical Committee 9.9 of the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) is currently working to update that Society’s
Guideline for Commissioning of HVAC Systems, which was last published in 1996 as
ASHRAE Guideline 1-1996. While the next update will still address only HVAC systems in detail, it will include links and references to commissioning of other systems and the building as a whole, according to Grondzik. Meanwhile, the National Institute of Building Sciences is coordinating an initiative to develop a comprehensive document on total building commissioning. Various trade and professional associations are developing guidelines for their areas of expertise, which will eventually be compiled into one integrated approach.
While the practices are evolving, the market for commissioning appears to be expanding rapidly. “Two years ago we were doing it only for a handful of more sophisticated clients,” reports Odom. “Now it’s a large portion of our business at CH2M HILL’s Facilities Group.” Code requirements will also serve to speed the acceptance of commissioning. Leading the way is the Seattle Energy Code, which now includes requirements for commissioning of mechanical systems and lighting controls in nonresidential buildings.
While the exact mechanisms remain in flux, commissioning—or a similar process under another name—is essential in complex and challenging buildings. Without focused attention, the needs and intentions of the owner are all too likely to be compromised on the long route through design and construction to occupancy. In almost every building type, better care throughout the process will enhance all aspects of building performance, including environmental measures.
The Building Commissioning Handbook by John A. Heinz, P.E., offers a good overview along with sample language for including commissioning in project specifications. Price: $75. Order from APPA Publications: 703/549-2772,