Possible Changes in Energy Codes Reviewed at Recent ICC Hearings

The following report was prepared by Julie Ruth, code consultant for the American Architectural Manufacturers Association.

The International Code Council code development hearings that concluded Oct. 1 provided some mixed signals for the residential window and door industry, most notably on the energy code front.

The hearings for the ICC 2006/2007 code change cycle, held in Lake Buena Vista, FL, also saw the ICC code change committees take action on a number of non-energy code change proposals of interest to the fenestration community.

Both the International Energy Conservation Code Committee and the International Residential Code–Building and Energy Committee reviewed numerous proposals for energy efficiency of building construction. The IRC applies to one and two family dwellings and townhouses three stories or less in height.

The residential provisions of the IECC apply to apartment buildings and condominiums, as well as townhouses and one- and two-family dwellings three stories or less in height. Which one applies to a particular structure depends upon which code has been adopted and is being enforced in the jurisdiction in which construction is taking place. As a general rule, the IECC committee tended to be more conservative in its decisions than the IRC–B&E committee.

Performance Caps
The IRC–B&E committee approved two proposals (EC58/EC59) to remove performance caps on residential fenestration when performance-based design is used. The IECC committee, on the other hand, not only disapproved these proposals, but also disapproved a proposal that would have made the performance caps in the IECC less stringent.

The result could be performance caps in all climate zones for residences designed under the IECC and no performance caps in any climate zones for residences built under the IRC, if the decisions of both committees are upheld through the final action hearings next May.

The 2006 IECC restricts the maximum area weighted average U-factor of residential fenestration to 0.40 in climate zones 6 to 8 and to 0.48 in climate zones 4 and 5 when performance-based design is done. When performance-based design is used in climate zones 1 to 3, the maximum area weighted average SHGC is restricted to 0.50 in the 2006 IECC.

U-factor/SHGC Trade Offs
Similarly, the IRC–B&E committee also approved Part II of a proposal (EC54) that will permit slightly higher U-factors when certain minimum SHGC are met in climate zones 6 to 8. Part I of the same proposal was disapproved by the IECC committee.

Again, if the decisions of both committees are upheld through the final action hearings, the provisions of the IECC for residential construction will vary from those of the IRC, with the IRC giving another option under prescriptive design that will not be available in the IECC.

Maximum SHGC
Although the IECC committee disapproved a proposal (EC 35) that would have lowered the SHGC for residential fenestration from 0.40 to 0.25 in climate zones 1 to 3, it approved a similar proposal (EC 39) that lowered it from 0.40 to 0.37 in the same climate zones.

Since the change to 0.37 was only proposed and approved for residential construction built under the provisions of the IECC, creating another inconsistency between the IECC and the IRC, which requires a SHGC of 0.4 for residential construction in the same climate zones.

An inconsistency was also created within the IECC itself between the provisions for residential and commercial glazing, with the later establishing a maximum SHGC of 0.40 for glazing in climate zones 1 to 3 when a wide, overhanging projection is provided.

Proposals that brought in trade offs for residential construction, such as establishing a minimum SHGC in northern climates (EC 44 & EC 45), permitting higher SHGC in southern climate zones when an overhanging projection is provided (EC 40 & EC 41) and permitting low rise residential buildings to be designed in compliance with all the provisions of the IECC for commercial buildings, were also disapproved by the IECC committee and by the IRC–B&E committee when presented to them.

Window Installation
A proposal (RB244) to separate the window and door installation provisions of the IRC from the provisions for flashing the window and door opening was approved, but with a modification stating that the windows and doors shall be installed and flashed in accordance with the manufacturer’s installation instructions. The new language then goes on to say that window and door openings shall be flashed in accordance with the appropriate section of the IRC (Section 703.8).

For the present, code officials are looking to the window and door manufacturers to provide instructions on how their products are to be flashed, in accordance with the provisions of the IRC. Several code officials also expressed their wish to see a mandatory version of ASTM E2112 introduced into the IRC and the International Building Code.

Exterior Door Thresholds
The provision that permitted the threshold of nonrequired exterior doors to be up to 7¾ inches higher than the floor on either side of the door was removed from the IRC.

A second proposal (RB247) that would have created a similar provision in a different section of the IRC also was disapproved based on problems with the language.

Protection of Openings
Two proposals (S19 & S20) to change the provisions of the IBC for the use of wood structural panels to protect openings in exterior walls in wind-borne debris areas were approved.

Taken together, the two proposals restrict use of wood structural panels to one- and two-family homes, townhouses and assisted living facilities that are not more than 45 feet in height in wind speed areas that do not exceed 140 mph, with permanent anchoring for the panels provided in the exterior wall of the residences.

The second proposal also increases the size, embedment depth and ultimate withdrawal capacity of the anchors provided to secure the panels to the building.

Safety Glazing
A proposal (S105) permitting glazing that complies with certain classes of safety glazing in ANSI Z97.1 to be used in hazardous locations that are not required by federal law to comply with CPSC 16 CFR Part 1201 was approved for the IBC, but not for the IRC.

The classes of safety glazing to be permitted are Class A and B, which correspond with Category I and II safety glazing established in CPSC 16 CFR Part 1201.

Hazardous locations where Class A or B safety glazing will be permitted include glazing near stairways and ramps and lights of glass greater than 9 square feet in area that are near walkways.

Wind Tunnel Testing
A proposal to permit use of wind tunnel testing in accordance with Section 6.6 of ASCE 7 to determine the design wind loads upon a building was approved for the IBC.

The proposal gave some additional information on how Section 6.6 of ASCE 7 is to be applied. These include limiting the design wind pressures used to be at least 80 percent of those calculated for the “away from corners” portion of the exterior walls and roof, in accordance with ASCE 7.

Skylights
Two proposals to change the structural requirements for skylights were disapproved, one by the IBC–Structural Committee and one by the IRC–B&E committee.

The first proposal would have required skylights to be rated for a minimum performance class of 20 psf by testing to an ultimate positive pressure of 60 psf and an ultimate negative pressure of 40 psf. This would have established a safety factor of three for positive pressure of skylights rated for 20 psf only, which would have been inconsistent with the rest of the requirements of the IBC that applied a safety factor of 2 to determine both the positive and negative test pressure of skylights.

The second proposal would have recognized the use of an AAMA 506 tag to demonstrate impact resistance of unit skylights in the IRC. A similar provision currently exists in the 2006 IRC for vertical fenestration. Use of the AAMA 506 tag to demonstrate the impact resistance of fenestration is limited to products that have been tested and labeled in accordance with AAMA/NWWDA 101/I.S.2 – 97 or AAMA/WDMA/CSA 101/I.S.2/A440 – 05.

Next Steps
The next step in the code development process will be the development and submittal of public comments on the committee actions. Anyone who wishes to challenge the code change committee’s action on any proposal can submit a public comment seeking a different action on that proposal. The deadline for submittal of public comments is January 24, 2007.

The ICC membership will hear the public comments during final action hearings for the 2006/2007 code change process in Rochester, NY, May 22-25. At that time, active members of the ICC (code and fire officials) will determine the final action on each code change proposal submitted for this cycle. The results of these final actions will be included in a 2008 Supplement to the 2006 International Codes.

More information on codes related to window and door performance is available at the American Architectural Manufacturers Association Web site.

Julie Ruth may be reached via email.