Code Proposals Related to Daylight Zones, Skylights and Replacement Fenestration Approved

The International Code Council’s (ICC) committee action hearings continued over the weekend in Dallas with the approval of several proposals related to the commercial portion of the International Energy Conservation Code (IECC).

Among these, CE36-13, which aimed to add a requirement that the location of daylight zones on floor plans be included in construction documents to section C103.2 of the IECC, “Information on construction documents,” was approved.

The proposal was filed by Thomas Culp of Birch Point Consulting LLC, representing the Glazing Industry Code Committee (GICC).

“This proposal serves two purposes,” wrote Culp in his proposal. “First, this will help code enforcement by reformatting this section as a clear list rather than a cluttered paragraph, and also adding a requirement to show the location of daylight zones on floor plans, which will aid enforcement when daylight zones are used in sections C402.3.1-C402.3.3 (window and skylight area and properties), C405.2.2.3 (daylight controls) and C406.3 (efficient lighting path).

He continued, “Second, this will encourage the architect to consider daylighting geometry earlier in the design process. While this is already good practice amongst leading architects, it is still common that by the time a lighting/daylighting designer is engaged on a project, the envelope geometry and properties have already been locked in, and are difficult and expensive to change. This change will help bring consideration of daylight zones earlier into the process.”

The committee also approved CE75-13, which will adapt section C401.2.2 of the IECC. Proposed by a variety of groups including the Alliance to Save Energy and the Energy Efficient Codes Coalition, the proposal adds new text to the code that reads as follows:

“C401.2.2 Application to replacement fenestration products. Where some or all of an existing fenestration unit is replaced with a new fenestration product, including sash and glazing, the replacement fenestration unit shall meet the applicable requirements for U-factor and SHGC in Table C402.3.

Exception: An area-weighted average of the U-factor of replacement fenestration products being installed in the building for each fenestration product category listed in Table C402.3 shall be permitted to satisfy the U-factor requirements for each fenestration product category listed in Table C402.3. Individual fenestration products from different product categories listed in Table C402.3 shall not be combined in calculating the area-weighted average U-factor.”

“The purpose of this code change is to create a new code section to clarify that whenever an entire new fenestration product or assembly replaces some or all of an existing fenestration product (typically in the remodeling or modernizing of an existing building), the new fenestration product must meet the U-factor and SHGC requirements of the fenestration table,” wrote the groups behind the proposal. “Section C401.2.1 of the 2012 IECC already requires that additions, alterations and repairs comply with C402 (thermal building envelope) – as a result this proposal does not add any additional requirements. However, this proposal will further clarify the application of the requirements, increase effective enforcement, and reduce the likelihood of confusion and differing interpretations.
Additionally, the proposal notes that this language has been in the residential chapter of the IECC since at least 2000.

CE148, also proposed by Culp on behalf of the GICC, was approved as well. The proposal will adjust section C402.3.2 of the IECC to change the definition of “minimum skylight fenestration area” to apply to a space greater than 2,500 square feet, rather than the previous 10,000 square feet.

“Separate analyses for ASHRAE 90.1 and California Title 24 have shown toplighting of larger open spaces to provide very cost effective energy savings, and that the size threshold may be significantly reduced from the current 10,000 feet,” wrote Culp in his proposal. “2008 Title 24 uses an 8,000-square-foot threshold, and will use 5,000-square-foot in the 2013 standard.”

He continued, “ASHRAE 90.1-2010 has already been at 5,000 square feet, and following a new cost effectiveness analysis by Pacific Northwest National Laboratory, is now lowering it further to 2,500 square feet.”

Meanwhile, a proposal that would have lowered the U-factor requirements for fenestration in climate zones 3 and 5 in Table C402.3 of the IECC was disapproved. The proponents had reasoned that the proposal would “improve the efficiency of commercial vertical windows in climate zones 3 and 5 by lowering U-factors to the same level as the U-factors in climate zones 4 and 6 respectively.”

On the International Residential Code (IRC), a proposal by Jeff Inks representing the Window and Door Manufacturers Association (WDMA), to add section R308.6.9.1 to Chapter 44 of the code also was approved.

The section, titled “comparative analysis for glass-glazed unit skylights” describes structural wind load design pressure requirements and cites WDMA I.S. 11.

“Comparative analysis based on accepted engineering methods provides a proven, accurate and reliable means for determining design pressures of different sized products within a fenestration product line based on testing of specimen unit/s from the respective line,” wrote Inks in his proposal. “This alleviates the need for costly testing of all sizes within the line saving considerable construction costs and providing greater design flexibility without incurring additional time and costs, especially for specialty/custom products, for testing that isn’t necessary in order to determine the correct [design pressure].

He continued, “Currently the IRC only allows comparative analysis for windows and doors in Section 612.3.1 which has been and continues to be widely utilized for those products for the reasons stated above. Since comparative analysis as noted above is equally applicable to glass-glazed unit skylights, it should also be permitted by the IRC for them.”

The code hearings continue through tomorrow. Stay tuned to