Last Chance for 2009 I-Codes

Many public comments submitted related to energy conservation
Julie Ruth
August 15, 2008
COLUMN : Code Arena | Codes & Standards, Energy Efficiency

The last opportunity to submit proposed revised language for the 2009 International Codes passed in June with the deadline for public comments. Comments were limited to those topics already addressed by code change proposals that were submitted in 2007 and heard during the International Code Council code development hearings in Palm Springs in February 2008. ICC received over 1,000 public comments on the 2,000 original proposals submitted for the 2007/2008 ICC code change cycle.

Typically, comments are only received on about a third of the original proposals, with the committee action on the remaining two thirds upheld by a block vote at the final action hearings. Since more than one public comment may address the same original proposal we won’t know what the actual distribution of proposals whose committee action was challenged to proposals whose committee action was not challenged will be until the agenda for the final hearings is published this month.

With the nationwide emphasis on green building, and federal legislation to mandate increased efficiency of the nation’s energy conservation codes threatening, however, it’s fairly clear that the primary focus for ICC public comments this time around will again be energy conservation.

RESIDENTIAL ENERGY

Of particular concern to our industry is the difference in maximum U-factor and SHGC for residential fenestration in climate zones 1 to 4 that was approved for the International Residential Code and the International Energy Conservation Code during the Palm Springs hearings. The changes to maximum U-factor were specific to climate zones 1 to 4 and included consideration of impact resistant glass, while the changes to maximum SHGC were specific to climate zones 1 to 3 and included consideration of overhanging projections. The IECC committee voted to drastically reduce the maximum U-factors for residential fenestration in climate zones 1 – 4.

Although the IRC building and energy committee also voted to reduce the maximum U-factors in climate zones 1-3, they did not vote to reduce them as drastically as the IECC committee did, they did not reduce the U-factor in climate zone 4 and they added a footnote that permitted higher U-factors for impact resistant glass in climate zones 1 to 3.

Having two different sets of values in the International Codes for residential fenestration could lead to a lot of confusion. It is also contrary to the original intent of the development of the International Codes, which was to have one set of code requirements for the entire country. Not only does the potential exist for there to be a wide variation in the requirements for residential fenestration just from one community to a neighboring community, but the potential exists for there to be conflict in the requirements within any single jurisdiction that adopts both the 2009 IRC and 2009 IECC.

The argument that there should only be one set of values for all residential fenestration in the International Codes does not seem like such an extreme position. If you accept that argument then the question becomes “Which set of values should be used?” The U-factors approved by the IECC committee are lower, and theoretically would save more energy, but how significant is U-factor in the South, anyway? Would it be cost effective to apply the values approved by the IECC committee to all fenestration products, including impact resistant ones? There are some who would argue that having a low U-factor in the South is not such a good thing, anyway, because it will contribute to the building’s retention of heat during the times of day when the outside temperature is somewhat moderate and it is desirable to have the heat that has built up in the building during the day emitted into the night sky. Perhaps the answer to “What should the final values be?” and “Should there be different values for impact resistant glass?” should be somewhere in the middle between what was approved for the IRC and what was approved for the IECC.

Between the hearings in February and the public comment deadline in June various industry groups met and developed their own position. AAMA submitted public comments for one set of values for both the IRC and IECC. Table 1 compares the current U-factors of both the IRC and IECC with the values that were approved by the IRC committee, the values approved by the IECC committee, and the proposed maximum U-factors submitted by AAMA.

Maximum U-factor for Residential Fenestration

(using the prescriptive method of compliance)

Climate Zones

Current IRC & IECC

Approved for IRC

Approved for IECC

Proposed by AAMA

1

1.20

1.20

0.65

1.20

2

0.75

0.65i

0.50

0.65i

3

0.65

0.55i

0.40

0.50i

4

0.40

0.40

0.35

0.38

5-8

0.35

No change

No change

0.35

Table 1— iFor impact resistant fenestration complying with Section R301.2.1.2, the maximum U-factor shall be 1.20 in Climate Zone 2, and 0.70 in Climate Zone 3. AAMA is promoting maximum U-factors of 0.75 in Zone 2 and 0.65 in Zone 3.

A discrepancy also occurred between the SHGC approved by the IECC committee and what was retained and revised by the IRC committee. IECC voted to change the maximum SHGC in Climate zones 1 to 3 from 0.40 to 0.30, while the IRC group did not approve any changes to the maximum SHGC in these zones, but did approve adding a footnote that took into consideration shading of the glass by an overhanging eave, awning, canopy or other type of projection. The footnote says that if the distance the overhanging element projects from the face of the building is at least half the height from the bottom of the glazing to the bottom of the projection, then the glazing is considered to have met the SHGC requirements of the code. In other words, glazing shaded by these rather wide projections would not be subject to SHGC limitations.

To what extent should shading provided by projections be taken into account when determining the maximum SHGC of the glazing? Is lower visible light transmittance through glass with a lower SHGC a concern? As with U-factor, various industry groups met between February and June and discussed these questions. AAMA submitted a public comment to revise the maximum SHGC to 0.35 in both the IRC and IECC, with a footnote that retains the maximum SHGC of 0.40 for impact resistant glass.

WINDOW SILL HEIGHTS

The ICC code technology committee submitted a proposal (RB 173) that would have permitted the sills of operable windows to be lower than 24 inches above the floor if the window is equipped with a window opening limiting device that limits the initial opening size of the window to 4 inches, but that can be released to permit the window to be opened to a greater size.

The proposal was disapproved by both the IRC building and energy committee and the International Building Code fire safety committee. In response, the ICC code technology committee submitted three public comments on this proposal. The first, PC1, would raise the minimum sill height from 24 inches to 36 inches. The second, PC2, would replace the requirements for window opening limiting devices that were in the original RB173 with reference to ASTM F2090 for Window Opening Control Devices.

Finally, PC3 would modify the original RB173 to remove reference to the Screen Manufacturers Association standard and clarify the requirements for operable sections of windows that are within 24 inches of the floor. During the final hearings, a proposal can be approved as modified by any combination of the submitted public comments. So it is possible, for example, that the proposal could be approved with the minimum sill height raised to 36 inches and the edition of ASTM F2090 that is currently under revision referenced for the criteria for window opening control devices.

DOOR SIZE AND THRESHOLDS

Although the members of the AAMA door codes committee and the AAMA codes working group have not recommended that AAMA submit a public comment on the S141 proposal that covers side-hinged doors, they have recommended that AAMA submit public comments on other, hopefully less controversial, topics. These include clarification of the door size criteria, and threshold provisions at exterior doors of dwelling units.

During the process of trying to clarify the current requirements for door width in the IRC, a change was approved to the IBC that could increase the actual required height of door slabs, in some cases. The culprit was code change proposal E37. AAMA initially developed Part II of this proposal to change the current requirement of the IRC that egress doors be 36 inches wide to one that required egress doors provide a minimum clear width of 32 inches. To provide a clear width of 32 inches usually a nominally 36 inch wide door slab is required. This change to the IRC was approved by the IRC.

Along with addressing the width of the egress opening, AAMA sought to replace the current requirement that an egress door be 80 inches high with one that required a clear door opening height of 78 inches in both the IRC and IBC. To provide a clear opening height of 78 inches in most cases a door slab that is nominally 80 inches high would be required. The proposal was approved as submitted in the IRC, but approved with a modification that increased the proposed minimum height of the door opening to 80 inches in the IBC. AAMA submitted a public comment seeking to have the clear opening height returned to the initially proposed 78 inches in both the IRC and IBC.

AAMA also submitted a public comment on a proposal that would permit the height of thresholds of doors between a Type B dwelling unit and an exterior deck, patio or balcony to be included in the 4-inch step down that is permitted between the exterior deck, patio or balcony, and the interior dwelling space.

At the present time, the height of thresholds at these doors is limited to ¾ inch for sliding doors and ½ inch for all other doors, even though a 4 inch step down in permitted between the interior floor and the exterior deck, patio or balcony. The controversial S141 would have required all exterior swinging doors to be tested and labeled in accordance with AAMA/WDMA/CSA 101/I.S.2/A440. Currently both the 2006 IBC and 2006 IRC require windows, unit skylights and sliding doors to be tested and labeled in accordance with that standard. S141 was withdrawn during the February hearings, but it could come back if there are public comments supporting it.

FENESTRATION IN COMMERCIAL BUILDINGS

In the nonresidential arena, AAMA submitted a public comment that seeks recognition of AAMA 507 as a method of demonstrating U-factor and SHGC for curtain wall and storefront in commercial buildings. The proposal would require the AAMA 507 certificate of compliance to be signed by a registered design professional and would limit use of AAMA 507 to curtain wall and storefront. This limit is in response to concerns raised during the Palm Springs hearings that the original proposal (EC4), which did not include this limitation, could have been interpreted as allowing use of AAMA 507 for residential windows installed in commercial buildings.

AAMA also submitted a public comment that permits consideration of the area weighted average U-factor for the exterior envelop of commercial buildings. This would allow for trade-offs between various components of the exterior envelop, such as opaque portions of the exterior wall and glazed portions, or between skylights and sloped glazing, and opaque portions of the roof. A similar provision already exists in both the IECC and IRC for residential construction.

The original code change proposal, EC108, also permitted consideration of the area weighted average SHGC for the glazed portion of the exterior building envelop, but the latest AAMA proposal removes consideration of area weighted average SHGC. Another public comment to require daylighting with automatic lighting controls in very large spaces of single story stores, factories, educational buildings and warehouses was also submitted by AAMA.

The recommendation draws upon previous research that was partially funded by AAMA that demonstrated that significant energy savings could be achieved when skylights were installed and evenly distributed in the roof of these types of occupancies at 6 percent of the roof area, in combination with automatic lighting controls. A proposal that permits skylights to be exempt from the SHGC limits of ASHRAE 90.1 when combined with automatic lighting controls has been accepted into the next edition of ASHRAE 90.1. The ASHRAE 90.1 proposal is based upon the same research as the IECC proposal, but the IECC proposal goes one step further by mandating a certain amount of daylighting be provided in very specific areas.

What Next? The fate of all these proposals for the 2009 International Codes will be decided at ICC’s final action hearings. The hearings will take place September 17-23 at the Minneapolis Convention Center in Minneapolis, Minn.

Code Arena is brought to you by the America Architectural Manufacturers Association. Julie Ruth may be reached through AAMA at 847/303-5664 or via e-mail at julruth@aol.com.