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By Nancy B. Solomon, AIA

Exterior enclosure commissioning process

Meanwhile, on another front, NIBS is in the process of preparing a building-envelope commission guideline to be called NIBS Guideline 3-2005: Exterior Enclosure Technical Requirements for the Commissioning Process. This publication builds on—and is to be used in conjunction with—ASHRAE/NIBS Guideline 0-2005: The Commissioning Process. Guideline 0-2005, which outlines—without reference to a specific discipline—the basic procedures in the commissioning of any building component within a new or renovated project, was just approved in January by the ASHRAE board. A total of 14 guidelines, in addition to Guideline 0-2005, are anticipated to address the gamut of systems to be considered in a total building commissioning program.

 

The Massachusetts Board of Building Regulations and Standards asked BSA’s Building Envelope Committee—the precursor to BEC-Boston—to develop a series of sample construction details in support of the state’s commercial energy code, which had been revised to introduce, among other changes, requirements for air barriers within the building enclosure. The committee’s task force, chaired by Wagdy Anis, AIA, of Shepley Bulfinch Richardson and Abbott, produced drawings of six common wall assemblies for educational purposes only. The designs assume exterior conditions typical of Massachusetts, and a maximum of 35 percent interior relative humidity in winter. Air-barrier continuity is emphasized. Illustrations: Courtesy Shepley Bulfinch Richardson and Abbott

Building commissioning is a systematic process of quality control through the predesign, design, construction, occupancy, and operations phases to assure that the owner gets a building that functions as intended. “The intent is to prevent errors before they occur,” says Joseph J. Deringer, AIA, president of The Deringer Group in Berkeley, California, and chair of the NIBS Enclosure Commissioning Guideline Committee. Historically, commissioning had focused on the start-up of the mechanical system toward the end of the construction phase to assure that it was running properly and efficiently before handing the keys over to the owner. But as greater emphasis was placed on building performance as a whole, it became clear that such a quality-assurance program had to start at the beginning of a project and include other critical components, such as the building’s skin, which is at the interface of so many environmental systems, from temperature and lighting to moisture control.

The body of the envelope commissioning guidelines will be general enough to address the basic process for all building types, sizes, functions, ownership structures, and delivery methods. To begin the process, for example, the owner or owner’s representative should develop a comprehensive list of project requirements as early as possible in the building delivery process, preferably before design begins. These requirements will take into account the inherent trade-offs between quality and cost. The ASHRAE/NIBS guidelines call this the “Owner’s Project Requirements,” or OPR. The design team, in turn, responds to the OPR with the “Basis of Design,” or BOD. In the case of the building envelope, the BOD typically includes a description of each exterior envelope system option considered, including subsystems, materials, and components; a description of the interaction of the building exterior enclosure system with other building systems; the reasoning for the selection of the final building exterior enclosure system; and documentation of related assumptions, calculations, codes, and standards that were used in this decision-making process.

With the OPR and BOD established, the project team then proceeds according to a methodical and transparent series of checklists, peer reviews, mock-ups, in-situ testing, documentation, and staff training at appropriate stages in the process in order to avoid any miscommunication or misconceptions among the various parties.