Skylight Council Encourages Comments on ICC-ES
Requirements in Acceptance Criteria for Skylights
December 23, 2009
The American Architectural Manufacturers Association (AAMA) has
forwarded a member's request to parties following work on the International
Code Council's (ICC) Evaluation Service (ES) Acceptance Criteria
for Glass Glazed Unit Skylights and Sloped Glass Glazing and/or
Acceptance Criteria for Plastic Glazed Skylights that they
comment on whether or not to delete additional air infiltration
tests from Section A3.3 and the deletion of Section A6.2, which
currently requires the evaluation reports to indicate compliance
with the air infiltration conditions of acceptance.
According to the request from Roger LeBrun, product certification
engineer for VELUX America Inc. and a member of the AAMA Skylight
Council, "The same minor (but quite important) revision is
being made to two similar ICC-ES Skylight Acceptance Criteria, AC16
and AC17. It is intended to correct a misguided change ICC-ES Staff
decided to make when they did their last major overhaul for the
2006 codes, regarding the need for additional air leakage testing."
HERE to see the proposed changes and related documents, as well
as a link to the comment form.)
LeBrun explains, "From a unit skylight perspective, the AAMA/WDMA/CSA
101/I.S.2/A440 document referenced in the I-codes specifies that
air leakage testing is done on the 'gateway' size only (similar
to NFRC 400). At one time, two years ago or so, ICC-ES staff interpreted
the codes to require every specific size to meet the air leakage
limit, rather than a 'standard' size, and inserted additional testing
provisions as part of their overall 2006 IBC/IRC update of the AC16
and AC17 criteria.
"ICC-ES staff further assumed that skylight and TDD air leakage
was a function of perimeter length, rather than area, as for operable
windows. This assumption did not hold true for the vast majority
of skylights that are designed to shed condensation to the outside
through weep systems that do not change with size."
According to LeBrun, this posed a problem for two main reasons:
- "More units and more sizes had to be made, shipped to the
lab and tested for air leakage. This is not an insignificant cost
in a struggling economy and a suffering industry, and yields no
justifiable benefit; and
- If the weep system that passed on the standard size suddenly
was found to be too big for the sizes with lower perimeter-length/area
ratios, we would have to redesign products just to satisfy a code
misinterpretation by a non-code entity."
LeBrun adds, "By also pointing out that air needs to be replaced
in occupied spaces anyway, and that U-factor is also based on a
single number, standard size performance rating extended to all
similarly-built sizes, it was finally realized by staff that they
had overreached on this earlier additional requirement. ICC-ES staff
wisely eventually reconsidered and recommended a retraction be approved."
Members of the AAMA Skylight Council agreeing with the proposed
changes are urged to file a supporting comment to ensure the changes
are implemented. Those who disagree are asked to describe their
reasons in detail. There will be no related hearing, since the changes
are being balloted to the Evaluation Committee concurrent with the
public comment period.
The deadline to comment is January 4, 2010.
for more information on the proposed changes.
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