ICC Ratchets Down Energy Performance Requirements for 2012 IECC

November 9, 2010

The International Code Council has voted to eliminate provisions in the 2012 International Energy Conservation Code setting lower energy performance requirements for metal-framed fenestration products than for other types of fenestration in commercial construction.  Part of an effort to improve the energy efficiency of commercial and residential buildings built to the 2012 codes by 30 percent over those built to the 2006 editions, the change is one of several more stringent performance  requirements for windows, doors and skylights approved at last week's final action hearings in Charlotte, N.C.

Among the most significant decisions, ICC officials report, was a vote to eliminate distinct energy performance requirements within the International Residential Code.  Beginning with the 2012 editions, the IRC will reference the IECC for energy performance standards, just as the International Building Code references the IECC for commercial projects. 

Metal vs. Non-Metal
The decision to eliminate provisions allowing less stringent energy performance requirements for metal-framed fenestration products used in commercial construction was applauded by the Window & Door Manufacturers Association. WDMA has argued for years that the energy performance requirements within each climate zone should be uniform for all fenestration used in commercial construction, as they are for residential construction. reports Michael O'Brien, WDMA president. "This fixes a critical flaw in the IECC that discouraged the use of more efficient non-metal framed fenestration because of the unbalanced requirements," he says. "This is a very significant gain for balanced energy efficient codes and especially for WDMA members."

Julie Ruth, code consultant for the American Architectural Manufacturers Association, describes the commerial fenestration code changes as "significantly less onerous" than other proposals. The removal of the distinction between metal-framed and nonmetal framed fenestration in the prescriptive table for commercial fenestration was achieved by removing the current values for nonmetal framed fenestration completely; reducing the values for metal-framed curtain wall and storefront by approximately 10 percent and applying that to all fixed windows; and reducing the values for all other metal framed fenestration by 10 percent or less and applying those to all operable windows, she explains. Other proposals would have reduced the U-factors by 20 percent to 30 percent for some products and AAMA was successful in defeating these, she adds.

Along with the elimination of separate criteria for metal-framed fenestratuion under the 2012 IECC, exceptions allowing less stringent energy performance requirements for impact resistant glazing, and allowing site assembled fenestration to be exempt from air leakage testing were also removed, WDMA officials note.  The association had argued that such exceptions were no longer needed or otherwise justified and should be removed as part of the overall effort to improve the IECC.

WDMA officials were pleased with a number of other changes voted on, including the overturning of an earlier proposal to limit glazing area in residential construction to 20 percent of conditioned space; the rejection of proposals to remove to fenestration efficiency trade-off caps; new requirements for whole house air barrier testing; establishment of solar gain requirements for residential construction in IECC climate zone 4; reinstatement of more reasonable air infiltration rates for skylights; removal of unjustified additional insulation requirements for unit skylights; and rejection of proposals to impose EPA Lead Rule requirements for property maintenance and renovation.

WDMA also welcomed the elimination of separate energy provisions in the IRC.   "This change ensures that the energy provisions between the two codes are consistent," says Jeff Inks, vice president of code and regulatory affairs.  "It is also a very welcome relief from the additional time, effort and cost that was required by all stakeholders to maintain separate provisions in each code."

On the downside, according to WDMA, was a decision to reduce maximum infiltration rates for operable windows used in commercial construction by 30 percent. WDMA opposed the change, arguing that a reduction in maximum infiltration rates would result in very limited gains in building efficiency, if any, and that the reduction will impede window operability, especially for sliding products.

Positives for Skylights
Overall, AAMA was pleased with the results of the hearings too, Ruth reports. The approval of a single set of prescriptive values (U-factor and SHGC) for residential fenestration in all climate zones is a significant victory, with the values presenting significant energy savings, while relying upon products that are currently available in the marketplace, she states.  She also points to the removal of additional insulation requirements for unit skylights and the reinstatement of more reasonable air infiltration rates for skylights, also noted by WDMA, as positives.

Ruth also highlights a number of victories in the commercial skylight arena, including mandatory toplighting requirements in commercial applications greater than 10,000 square feet in area was approved. "AAMA has been promoting the benefit of daylighting in reducing energy cost for several years," she notes.  Those efforts have included AAMA-sponsored studies that show energy cost savings of up to 30 percent could be achieved by combining skylights with automatic lighting controls.  The new code provisions will now require that combination in much of the  country.  In addition, the 2012 IECC will permit skylight area of a roof to be increased from 3 percent to 5 percent when automatic lighting controls are provided–another initiative supported by AAMA, she notes.

Also building upon the recognition of the value of daylighting in reducing energy cost, AAMA was able to maintain the permitted window to wall ratio (WWR) for use of the prescriptive table for commercial construction at 40 percent when automatic lighting controls are provided. A reduction of the WWR from 40 percent to 30 percent had initially been approved during the 2009 code development hearings, she notes.  AAMA was also able to achieve clarification that the WWR limitation only applies to the vision area of the curtain wall or storefront system and not to opaque spandrel panels.

Look for a more detailed report on the 2012 ICC final action hearings from AAMA's Julie Ruth in the January/February issue of Window & Door.