The International Code Council (ICC) is breaking new ground with the International Green Construction Code (IgCC). Due this spring, it will be the first internationally acknowledged code focused on high-performance buildings. It contains a comprehensive and detailed treatment of high-performance-building strategies, including energy conservation and commissioning (Cx).
The IgCC began as a joint venture of the ICC and The American Institute of Architects (AIA) in 2009. The U.S. Green Building Council (USGBC), the Illuminating Engineering Society (IES), ASHRAE, and ASTM International subsequently lent their support.
The author of this article, a communicating member of the working committee that developed the Cx portions of the IgCC, was part of a team assembled by the AIA to review the code. This preview of the IgCC’s Cx provisions is based on Public Comment Version 2.0 from November 2010—the latest version of the IgCC available for reference—and the public-review comments accepted for inclusion in the code during the final action hearing Oct. 31, 2011, in Phoenix. Although the final code will be a bit different, the discussion contained in this article embodies the intent of the Cx sections.
The IgCC requires Cx for many disciplines involved in building design, construction, and operation, including site-impact mitigation, soil testing, HVAC design and operation, lighting and envelope validation, and post-occupancy inspection and monitoring. The code strives to define and illustrate the basic and more advanced facets of “total building commissioning,” which one day may be required by law throughout the United States.
The IgCC uses the model-code approach, which enables communities to tailor requirements to their needs. Most parts of the code are formatted with checklists allowing authorities having jurisdiction to choose the degree of detail and rigor required. ANSI/ASHRAE/USGBC/IES Standard 189.1-2011, Standard for the Design of High-Performance, Green Buildings Except Low-Rise Residential Buildings, is a jurisdictional compliance option. Cx usually is mandatory, regardless of the compliance route chosen.
Stating the Obvious
All Cx guidelines in the United States would benefit from borrowing a page from The Chartered Institution of Building Services Engineers’ (CIBSE’s) CIBSE Commissioning Code M: Commissioning Management, which states, “Building-services plant and control systems should be inherently commissionable,” and, “The contractor and client should allow sufficient time for the complete commissioning process and ensure integration into the overall program.”
Although primarily a quality-assurance process, Cx is the first step in continuous preventive maintenance. If a piece of equipment or a system cannot be commissioned, it cannot be maintained. For example, if the control panel on a variable-air-volume (VAV) terminal above a hard ceiling cannot be accessed for functional testing, it cannot be accessed for preventive maintenance, and in the long run, the unit will not be maintained. If large equipment, such as a boiler or chiller, lacks metrics proving its acceptability, it lacks benchmarks that will become future indicators of its correct operation.
Although the IgCC requires access for Cx, it does not require that systems be designed for Cx. In other words, it lacks the requirement that equipment and systems be inherently commissionable and, thus, inherently maintainable.
Scope of Cx
In many codes and guidelines, Cx is required for energy-consuming systems, such as heating, ventilation, cooling, and lighting. The IgCC expands on this by including landscape and site work, rainwater and wastewater reuse, more extensive envelope requirements, noise and radon mitigation, and more. ASHRAE has taken a more long-term approach, creating a fundamental Cx guideline (ASHRAE Guideline 0-2005, The Commissioning Process) and following that with application guides for various building components. These components reach into every aspect of a building, including walls, roofs, windows, doors, and, eventually, furniture and interior finishes.
Indoor Environmental Conditions
The IgCC emphasizes minimal energy consumption and the resulting benefits of lower operating costs and carbon-dioxide emissions, citing indoor environmental quality (IEQ) as one of a dozen factors to be considered in the recommissioning of a building 18 to 24 months after occupancy. It does not specify specific techniques for measuring and maintaining a high level of IEQ.