©2013 This excerpt taken from the article of the same name which appeared in ASHRAE Journal, vol. 55, no. 6, June 2013.
By Dave McFarlane, Member ASHRAE
About the Author
Dave McFarlane is a principal project director at Atkins in Fort Myers, Fla.
This is the first of eight planned bimonthly articles that explain the technical commissioning process for new buildings. Some of the content is derived from ASHRAE Guideline 0-2005, The Commissioning Process (published 2005) and the National Environmental Balancing Bureau (NEBB) Whole Building Systems Technical Commissioning Procedural Standards Manual (revised April 2013).
Building owners who construct multiple commercial or institutional buildings in a given year have known for a long time that new buildings often do not perform as intended from an energy-use or comfort perspective. On the other hand, owners that construct only a few buildings in a lifetime may feel that start-up problems are just part of the construction process.
I have often heard A/E firms say, “We design buildings for extremes, so it will take about two years to work the bugs out.” And I’ve heard contractors say, “We can only do so much at start-up. You have to go through at least one set of heating and cooling seasons to get everything working right.”
The problem of poorly performing buildings has plagued the industry since long before I became involved in my first mechanical contracting business 35 years ago. As with many other firms, my team always did our best to respond to owner concerns. We returned to the project in response to complaints and made changes to satisfy the customer. Then, we would leave and hope to get through the one-year warranty period before the next complaint. I came to call this approach “commissioning by complaints.” That is, when the complaints stop, the commissioning process is complete.
Unfortunately, commissioning issues are still a big problem in 2013.
My experience indicates that most commissioning issues can be traced back to design, construction, testing, adjusting, and balancing (TAB), and control errors—and the problem has worsened over time. For example, the competitive nature of the bid market has forced designers to cut not only their pricing but their level of construction oversight. And for many buildings, construction managers no longer use a single general contractor to manage the entire process; instead, they award many contracts to multiple subcontractors.
Also, as subcontractors have become more specialized and systems more complex, coordination between “subs” has become more important—but more difficult. That’s because specialists don’t understand the “big picture” of how all of a building’s various systems interact, nor do they speak the same language as other trades. And the problem of design and construction errors is further compounded by the age-old problem of poor workmanship.
Finally, as construction times have become compressed, inadequate scheduling often causes subcontractors’ work to “bunch up” toward the end of the project. In a frenzied final push to project completion, walls are painted just in time for the control contractor to mount thermostats. Then carpet is installed, the building is cleaned—and the owner moves in. Due to time and/or budget constraints, the final system integration and verification too often doesn’t take place.
The result? A building with many occupant complaints that must be resolved by the owner’s new—and untrained—maintenance staff.
Effective Commissioning Process
The construction industry recognized these problems; and in the 1980s, the concept of “commissioning”—long used by the Navy to test new vessels and by industrial engineers to tune new processes—was adapted to direct the building construction process.
ASHRAE Guideline 0-2005, The Commissioning Process, defines building commissioning as “a quality-oriented process for achieving, verifying, and documenting that the performance of [a building’s] facilities, systems, and assemblies meets defined objectives and criteria.”
The U.S. Green Building Council (USGBC) also recognized the building performance problem and has factored the commissioning process into its construction guidelines as a prerequisite to obtaining LEED certification. The USGBC’s “enhanced commissioning” process can even result in a building earning additional LEED points.
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