Volume 39, Issue 6, June  2004


IECC Code Change Regarding Climate Zone Criteria Passed
During the International Code Council’s final action code hearings that took place last month in Overland Park, Kan., one particular proposal to the Inter-national Energy Conservation Code (IECC), which will affect non-residential construction, EC31-03/04, was heard and approved as amended by the committee, despite opposition. EC31 establishes criteria for factory-assembled and site-built fenestration products, and the code changes will revise the climate zone criteria for U-factors in regards to these products. Jeffrey Johnson of the New Buildings Institute was the proposal proponent. The proposal creates one glazing limit versus the multiple limits in the current IECC.

According to Johnson’s proposal, U-factors for site-built fenestration products were modified in all zones except zone 1 (see map above), making U-factors somewhat less restrictive than the original proposal, but also less stringent than requirements for factory-assembled units. In colder climates the site-built U-factor was modified to achieve an average U-factor between the factory-built and site-built items that is equivalent to the existing IECC, while still allowing a slightly higher value for the site-built products, often constructed with an aluminum frame.

The proposal, however, was not without opposition, as a number of comments were made against it. William E. Koffel of Koffel Associates Inc. representing the Glazing Industry Code Committee (GICC) was one 
who disapproved. According to Koffel’s comments, the proposal “made major changes to the thermal performance requirements of windows and doors installed in commercial buildings. This simplified table [802.2(2)], as ap-proved, significantly lowered the U-factor ratings without giving consideration to the overall window and wall area and the total effect on thermal performance … the new tables require an improved thermal transmittance of greater than 200 percent; a level that cannot be achieved by currently supplied aluminum windows and doors in this market …”

In addition, GICC also disapproved on the basis that it said there should be “no difference in the performance of factory-assembled products versus site-built products.”

“It does not make sense to base the thermal performance on where the product was assembled. The decision to factory assemble or field assemble windows for a commercial building is often not made until final contract negotiations for reasons that range from quality control to the available labor market at the time of construction,” commented Koffel.
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