Compromises on Proposed Requirements for Glass in 2010 Edition of
October 8, 2009
Several compromises were reached last week between the American
Society of Heating, Refrigerating, and Air-Conditioning Engineers
(ASHRAE) Envelope Subcommittee and members of the glass industry
during a meeting that took place on the 2010 revisions to Standard
90.1, Energy Standard for Buildings Except Low-Rise Residential
HERE for related story.)
Stanley Yee of the Façade Group made a presentation to the
group on behalf of the Glass Association of North America's (GANA)
ASHRAE Subcommittee. "The main message of the presentation
was essentially that the light to solar heat gain (LSG) criteria
of greater than 1.5 essentially eliminated the possibility of using
up to 60 percent of the high-performance glass products that are
available on the market today," Yee explains.
The GANA presentation also pointed out that mandating LSG of greater
than 1.5 could result in the misapplication of glass in the absence
of considering significant environmental factors such as orientation
and climate zone.
Another cause of concern for the GANA group was that there has been
no definition for dynamic glazing in the updated ASHRAE standard.
"Inadvertently, the proposal had basically eliminated the possibility
of using dynamic glazing, which to the [GANA] group was rather intriguing
considering that the Department of Energy has conceptually acknowledged
that it is a step in the right direction as far as technology goes
and trying to achieve net zero-energy."
In the end, the Envelope Subcommittee ceded some compromises.
"The end result was that they had reduced the 1.5 criteria
to 1.25, center of glass," Yee says. In addition, he adds,
"We were able to convince the Envelope Subcommittee to accept
the criteria associated with using affective aperture."
He noted that the Envelope Subcommittee also opted to create a new
track for outlining information specifically on dynamic glazing.
Yee is reluctant to call the compromise an outright victory, "Because,"
he says, "we haven't really assessed fully what the implications
will be of what we've landed on."
Moreover, the ASHRAE Envelope Subcommittee made some new changes
to the performance path in the proposed standard updates.
"What we're talking about is the prescriptive path, which is
what probably 80 percent of the projects that get built in this
country are based on," Yee says. "[For] the 20 percent
on the performance path, or what's sometimes called the trade-off
path, they increased the requirement. It used to be the same requirement
as the prescriptive path."
Representatives from GANA, Guardian Glass, PPG Industries, AGC Flat
Glass and Pilkington North America attended the meeting. GANA encourages
other industry professionals to watch for the second round of public
review of the standard, anticipated in January.
For more information, CLICK
HERE to watch the Glass Association of North America's video
podcast concerning this issue.
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