GANA Voices Industry’s Objections to ASHRAE 90.1 Committee
from the Glass Association of North America (GANA) attended a June meeting
of the American Society of Heating, Refrigerating and Air Conditioning
Engineers (ASHRAE) 90.1 Committee to speak to the committee about the
proposed 30-percent window-to-wall ratio (WWR) limit included in the standard,
as well as other items (see November 2009 USGlass, page 14).
“We presented our concerns regarding the 30-percent WWR limit, lack of
connection between the visible transmittance (VT)/solar heat gain coefficient
(SGHC) requirement and lighting controls, U-factor and SHGC criteria inconsistent
with the National Buildings Institute proposal to the International Energy
Conservation Code and the lack of glazing representation,” says Dr. Tom
Culp, energy code consultant for GANA and the Aluminum Extruders Council.
“The presentations were well received, but it did not change the outcome,”
He continues, “Pending any successful appeals, the 2010 version of ASHRAE
90.1 would include both aspects: a prescriptive limit of 30 percent WWR,
but also the prescriptive option to use 40 percent WWR with daylighting
controls. Larger glass areas would have to use the performance path.”
GANA says such a result would be a success for glazing manufacturers.
“Although the added controls are expensive and may limit use of this option,
this is a significant achievement,” Culp explains. “This gives us more
options, and also sets a precedent that more glass is not ‘always bad,’
preventing any further reductions in glass area in the future.”
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