A proposal that will adapt the International Energy Conservation Code’s (IECC) commercial portion to note that doors with more than 50-percent glass area “shall meet the provisions of Section C402.3.3 for vertical fenestration” was passed this week during the International Code Council’s committee hearings in Dallas.
The proposal, CE133-13, was put forth by Jeremiah Williams of the U.S. Department of Energy. In addition, the change adds a section to the code that defines “opaque doors” as “doors that are at least 50-percent opaque in surface area.”
“As currently defined, doors are considered fenestration regardless of the percentage of glazing they contain,” wrote Williams in his proposal. “As such, users of the code would logically begin to look for and address the requirements for doors in the fenestration section of the code. Instead the provisions for opaque doors (those with less than 50 percent glass area) are located in Section C402.2.7 covering opaque assemblies. One could conclude from a review of this provision in the opaque section of the code that any door with at least 50-percent glass area must be fenestration. This proposal clarifies when doors are considered part of the opaque wall and subject to thermal requirements for the wall, and when doors are fenestration and subject to those requirements.
He continued, “Relocation of the door provisions to the fenestration section of the code is appropriate, and from there doors that are opaque can be correctly referred back to the sections of the code addressing opaque assemblies and components. Note also the term glass area technically precludes consideration of other non-opaque materials. The proposed code change addresses this by using opaque area as the metric.”
Meanwhile, a proposal seeking to add a section about “daylight zones” to the code was disapproved. The proposal was made by Thomas Culp of Birch Point Consulting LLC, representing the Glazing Industry Code Committee (GICC).
Had CE152-13 been passed, the section would have described daylight zones as follows: “In buildings not greater than two stories above grade plane, not less than 10 percent of the net floor area shall be located within a daylight zone. In buildings three or more stories above grade plane, not less than 5 percent of the net floor area shall be located within a daylight zone.”
The GICC reasoned that this proposal “would require a minimum daylight area similar in concept to the 2012 International Green Construction Code (IGCC), but at [a] much less aggressive level (only one-fifth of the IGCC) and with a simplified approach.”
“… This proposal is meant to only be a simple base-level requirement to ensure that building designers address daylighting and glazing layout, while being easy enough to provide flexibility for different space and building types and not require any gross changes in building geometry,” wrote Culp. “Exceptions are included for spaces where daylighting would interfere with the function of the space, provide little benefit or not be feasible.”
The GICC further reasoned that the proposal would have “help[ed] improve layout and use of glazing that would have been installed anyway, but this [would] increase the cost of construction in some buildings where there would have been insufficient fenestration and daylighting.”
A proposal that aimed to “strengthen the [solar heat gain coefficient] requirement for vertical fenestration in climate zones 4 – 6 from 0.40 to 0.25, thereby increasing the energy efficiency of vertical fenestration in these climates” also was disapproved. CE145-13 was proposed by Brian Dean, ICF International, representing Energy Efficient Codes Coalition; Garrett Stone, Brickfield Burchette Ritts & Stone PC; Jeff Harris, Alliance to Save Energy; Harry Misuriello, American Council for an Energy-Efficient Economy; Bill Prindle, Energy Efficient Codes Coalition; and Don Vigneau, Northeast Energy Efficiency Partnerships.
Specifically, CE145-13 would have adjusted the SHGC requirements in Table C402.3 of the IECC.
“The level of solar heat gain, whether 0.40 or 0.25, is simply a choice of low-E coatings and does not involve significant increases in cost; there is no good reason not to capture the benefit of reducing the requirement to 0.25,” wrote the proponents of the change.
Dean Harris, Prindle, Misuriello and Vigneau also made a proposal related to dynamic glazing that was disapproved. CE159-13 sought to change Section C402.3.3.5 of the IECC, adding the following wording (additions underlined):
C402.3.3.5 Dynamic Glazing. For compliance with Section C402.3.3, the SHGC for dynamic glazing products shall be determined using the manufacturer’s average of the product’s lowest-rated and highest SHGC value from the product’s label, and the VT/SHGC ratio shall be determined using the maximum VT and maximum SHGC using the average of the product’s lowest and highest VT value from the product’s label. Dynamic glazing shall be considered separately from other fenestration, and area-weighted averaging with other fenestration that is not dynamic glazing shall not be permitted.
“The purpose of the proposed code change is to correct how the SHGC and VT are determined for dynamic glazing to reflect that there is no guarantee that dynamic glazing will be operated to minimize either SHGC or VT,” wrote the proponents. “Current dynamic glazing assumptions in the IECC are physically impossible and are inconsistent with fenestration product labels.”
The hearings wrap up today. Stay tuned to usglassmag.com for the latest.