While the International Code Council, Washington, D.C., has tackled numerous aspects of green construction in its building codes, energy efficiency is the aspect most clearly defined and addressed in the codes. The growing focus on green construction in the United States has intensified the ICC's emphasis on these efficiency provisions.
Evidence of this was apparent when the International Energy Conservation Code Committee met during the ICC Code Development Hearings in Palm Springs, Calif., Feb. 18-March 1, 2008. In regard to commercial fenestration, the IECC committee's actions were mixed. The committee tended to vote against proposals that could have been beneficial to our industry, including a proposal that would have permitted the use of AAMA 507 to determine U-factor and solar heat gain coefficient of fenestration, and a proposal that took into consideration the benefits of daylighting in reducing lighting power demand.
The committee, however, disapproved proposals that could have caused our industry quite a bit of pain, including a proposal that would have established more stringent U-factor requirements for glazing in commercial build- ings, and a proposal to remove consideration of the benefits of shading when establishing solar heat gain coefficient.
Probably the most significant change approved by the IECC committee in Palm Springs was the removal of a provision that permitted the IECC to be used in conjunction with ASHRAE. The provision had allowed the use of the IECC used for some components, such as the HVAC system, or the lighting, and the use ASHRAE for others, such as the building envelope. Although this proposal was approved, a separate proposal that would have removed use of ASHRAE 90.1 in its entirety as an option was disapproved.
Coupled with other recent changes to the IECC, the approved change has the potential to push the designer to use ASHRAE 90.1 for the entire building any time the provisions of the IECC mandate design elements that are simply not cost effective.
A similar glazing-related issue arose during the previous ICC code change cycle. The maximum solar heat gain coefficient for skylights, including sloped glazing, was lowered to the point that the ability of the skylight to contribute toward daylighting was significantly reduced. The prescriptive provisions of ASHRAE 90.1 were already more friendly toward overhead glazing because it permitted skylights to constitute up to 5 percent of the roof area versus the 3 percent permitted in the IECC. Current indications are that the next edition of ASHRAE 90.1 also will include a provision that permits skylights to be exempt from SHGC limitations when automatic lighting controls are provided.
Given the action of the IECC committee in Palm Springs, however, a building designer would need to design their entire building using ASHRAE 90.1 to take advantage of these more friendly provisions. This means they would have to design their HVAC and lighting system in accordance with ASHRAE 90.1 in order to enjoy greater freedom in terms of the skylights they are going to install in the building.
In addition to the removal of the ASHRAE provision, the IECC committee approved several other green proposals, including the update of standards from the National Fenestration Rating Council, Greenbelt, Md. NFRC 100, 200 and 400 will be updated to the 2004 edition. The committee also approved a proposal that established separate criteria for the opaque elements of the exterior building envelope for high-rise residential buildings. The latter could potentially pave the way for separate criteria for fenestration in high-rise residential buildings.
The action of the IECC committee will be revisited during the ICC Final Action Hearings in Minneapolis, Sept. 17-23. The industry should keep watch on what is overturned by the ICC membership during those hearings, and what is eventually adopted and enforced as the next edition of the energy code by various U.S. jurisdictions.
Energy-efficiency committee actions in Palm Springs
* Removed a provision that allowed mixed use of ASHRAE 90.1 and IECC-use of ASHRAE 90.1 in its entirety, as an option, was retained
* Approved a proposal to establish separate criteria for the opaque elements of the exterior building envelope of high-rise residential buildings
* Updated NFRC standards, including NFRC 100, 200 and 400.