Monday, July 19, 2010

Technical Committee Discusses U-factor, SHGC Ballots

The Technical Committee block began today with the Air Leakage, U-factor, and Solar Heat Gain Subcommittees meeting to bring the first day of NFRC’s Virtual Committee Week Meeting to a close.

Air Leakage Subcommittee

The Air Leakage Subcommittee reported that it has nothing active for the moment.

U-factor Subcommittee Considers Three Ballots

NFRC 100 Garage Door Ballot. This ballot is intended to delete language addressing specimen panel number and height requirements in Section 5.5.1 A. In many cases, manufacturers seeking U-factor ratings in accordance with NFRC 100 are not tooled to produce 21”height sections for some door models and also may not use a four-panel configuration. Therefore, the standard should only require that the specimen fill a 7’ by 7’ opening.

After some discussion considering the specifics of the wording, a motion from Mike Thoman to move the language as balloted forward for approval passed unanimously.

NFRC 100 Sash Kit Ballot. This ballot is intended to revise the language regarding sash kits of any operator type. The intent of Option two of Section 5.1.2 in NFRC 100 is to allow the manufacturer of a sash kit of any operator type to use their existing whole product line rating if the sash in the kit and the product line are identical in material and design. Therefore, this ballot is presented to clarify this intent in NFRC 100.

One negative that arose was that the ballot contains certification language that does not belong in the technical document. Mike Thoman said a task group will be formed to revise the language and present a revised document at a later date. All associated negatives will be shared with task group.

NFRC 100 Table 4-3 Wall and Sloped Glazing Ballot. The intent of this ballot is to revise Table 4-3 of NFRC 100 for Curtain Wall, Window Wall, and Sloped Glazing. Table 4-3 is being balloted to remove the product type “glazed wall” because the term is not used consistently with the rating applied to curtain walls and window walls.

A motion to move the language forward as balloted was approved with no negatives or comments.

Solar Heat Gain Subcommittee

The Solar Heat Gain Subcommittee discussed three ballots.

NFRC 100 Garage (Vehicular Access) Doors. This ballot is intended to delete language addressing specimen panel number and height requirements in Section 5.5.1 A.

One negative asked to consider adding the following language to the section: “In accordance with U-factor validation testing to NFRC 100 for simulated garage door products, sectional garage doors shall have the SHGC determined based on a specimen filling 2.13 (7’) wide by 2.13 (7’) tall opening (the aperture is smaller than the test specimen). Panel sizes and construction shall be in accordance with manufacturers normal specifications for a door of these dimensions.”

A motion to move the NFRC 200 garage door ballot forward to the Technical Committee for approval and implementation upon publication passed.

NFRC 200 Section 4.5.G Laminates. This ballot is intended to clarify language in NFRC 200-2010, Section 4.5, as it relates to laminated glazing in the matrix of center-of-glazing SHGC/VT options.

One negative focused on the verbiage, “ratings for products with obscured, frit, or wired glass and/or stained glass shall be deemed to be equivalent to the ratings for the clear glass” and whether it should be deleted in its entirety since Window 6 can model these variations to provide more accurate VT ratings. Following some discussion, the crux of the issue here focused on whether the word “frit” should be removed.

The negative was ultimately withdrawn, and a motion to move the 200 Section 4.5.G to the Technical Committee and to be implemented upon publication passed 15 – 9.

The final ballot in this block involved a revised draft of NFRC 201, which adds the capability to measure the SHGC of Tubular Daylighting Devices (TDD) in solar calorimeters.

Previously, the NFRC Technical Interpretation Number, TI-2003-22, has been used to specivy how to measure the SHGC of TDDs using NFRC 201. After refinement by the TDD SHGC Testing Group, the intent of the previous NFRC Technical Interpretation has been incorporated into the document and into a new Annex G. Only the sections of 201that were revised are included.

One of the negatives presented was that the incident light needs to be more accurately assessed to avoid significantly overstating the resulting SHGC. A motion to find this negative persuasive and substantive and return it to Task Group passed.

Technical Committee Resumes Tomorrow

The Technical Committee Block will resume at 11:00 a.m. (EDT) tomorrow, Tuesday, July 20, 2010 and run until 2:00 p.m. The Software, Condensation Resistance, Annual Energy Performance, Attachment, and CMA Subcommittees are scheduled to meet.

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