ICC Moves Toward One Set of Residential Energy Codes
To some extent, sitting in on International Code Council hearings is a bit like watching a professional baseball game. You have to know the rules, and the players involved, to actually understand what is happening. And sometimes, amid long periods of tedium, there are flairs of the dramatic.
Such was the case at the code development hearings, which started at the end of October and conclude this week in Baltimore, particularly in the case of the International Residential Code committee, which has been considering proposed changes to the energy provisions of the IRC.
First up were three proposals (RE1, RE2 and RE3) that would have replaced the existing energy provisions of the IRC with those of the International Energy Conservation Code for residential construction. Having two sets of I-Code requirements for basically the same building has been a source of massive confusion. Since both the ARRA and legislation pending to create a national energy code rely upon the IECC for residential construction, the provisions of the IRC are becoming less and less relevant. But all three proposals were disapproved.
The fourth proposal brought forward (RE4) would remove energy provisions from the IRC entirely, and instead refer to Chapter 4 of the IECC for these. This was the last chance to get down to just one set of energy requirements for residential construction. Although the vote of 6-5 was close, RE4 was also disapproved by the IRC committee.
That was not the end of the game, however. A floor motion was made to approve the proposal as submitted in front of the whole group. Under ICC procedures, a floor vote requires a two-thirds majority to be successful. The vote of 96-36, with 73 percent voting in favor of the motion, was sufficient to overturn the committee vote. As a result, the initial motion on RE4 at the final action hearings will be for approval as submitted. Only a simple majority of the code officials voting there will be needed to be uphold that approval, as opposed to a two-thirds majority for approval of any other proposal.
More Potential for Divergence
Over the course of the next few days, as the energy hearings proceeded for first the IRC, and then the IECC, the need to simply have one set of provisions for energy efficiency, under one committee, became even more clear. Until recently the provisions for energy in the IRC and IECC had been very similar. They have started to diverge over the past two editions. If the committee action that took place in Baltimore is upheld during the final action hearings next year, that divergence will become much greater.
For example, the IRC committee approved a proposal by the National Association of Home Builders (EC16) that gives four different set of values for vertical fenestration in seven different climate zones, based upon the compliance path chosen. This is radically different from the single set of requirements for vertical fenestration that were given in the proposal by the U.S. Department of Energy (EC13) that was approved by the IECC committee. The two maps below show the maximum U-factors and SHGCs for vertical fenestration given in the two proposals:
Maximum U-factors and SHGC for Vertical Fenestration in Residential Construction as approved by the IRC–Building & Energy Committee (EC16, Part II). Note: first number is maximum U-factor, second number is maximum SHGC.
Maximum U-factors and SHGC for Vertical Fenestration in Residential Construction as approved by the IECC Committee (EC13, Part I). Note: first number is maximum U-factor, second number is maximum SHGC.
The U-factors for skylights approved for skylights were more similar, with both EC16 and EC13 setting maximum U-factor for CZ1 = 0.75 and for CZ2 = 0.65. EC13 establishes a maximum U-factor for residential skylights in CZ3-8 = 0.55, while EC16 set it at 0.60. Proposals to create a separate SHGC for skylights in residential construction were unsuccessful. Most of these proposals would have raised the SHGC from the 0.30 limit currently given in the IECC for all fenestration in climate zones 1, 2 and 3. Proposals to lower the SHGC for all residential fenestration to 0.25 were also unsuccessful.
As with the provisions for residential energy, the hearings for energy efficiency in commercial buildings were jam packed with different approaches to achieving the “30 percent solution” targeted by DOE. A proposal (EC147) that would reduce the window-to-wall ratio for vertical fenestration from 40 percent to 30 percent, and reduce the air leakage rate for windows, doors and skylights to 0.2 cfm/ft2 was approved. The proponent, DOE, has promised to work with other interested parties to address their concerns during the public comment portion of the code change cycle. AAMA will be participating in that process.
Most of the proposals to revise Table 502.3 of the IECC lowered some or all of the U-factors. Another proposal from DOE that was approved (EC165) was one example. The U-factors and SHGCs approved are given in the table below:
a. The first U-factor applies when impact rated glazing is installed.
b. "All others" includes operable and fixed windows, and nonentrance doors.
c. Automatic daylighting controls shall meet the requirements of Section 505.2.2.3.3.
d. The SHGC for Climate Zones 1-6 can be increased to SHGC no greater than 0.60 if the visible transmittance (VT) is not less than 0.60 and automatic daylighting controls are installed that meet the requirements of Section 505.2.2.3.3.
Along with lowering the U-factors for commercial fenestration, EC165 adds a footnote to permit skylights up to 5 percent of the roof area when combined with automatic lighting controls. Recognition of the value of daylighting towards reducing lighting loads was included in this proposal, as it was in the approval of DOE proposal EC173 and AAMA proposal EC179. Taken together, these two proposals will require 50 percent of spaces greater than 10,000 square feet in offices, lobbies, atria, concourses, corridors, storage areas, gymnasiums/exercise centers, convention center, automotive services, manufacturing facilities, non-refrigerated warehouses, retail stores, distribution/sorting areas, transportation areas and workshops to be daylight zone under skylights.
The attempt to have AAMA 507 recognized for the determination of U-factor and SHGC of curtainwall and storefront was narrowly disapproved by a vote of 6-5 in spite of one committee member's comments that the 6 month delay needed to receive NFRC certification on a project was a major obstacle. Although the proposal (EC172) would have required the certificate of compliance to be signed by a registered design professional, the committee expressed concern that registered design professionals may not be willing to sign the certificate of compliance.