The Case for GANA
BEC Input Needed in All Divisions
by Chuck Knickerbocker
Having attended Building Envelope Contractors Division (BEC)
of Glass Association of North America (GANA) meetings in Vegas for most
of the last nine years, it’s only recently that I’ve learned that there’s
a lot more to GANA than BEC. Does BEC know what’s going on in the other
GANA divisions? The answer is probably not, if your experience has been
like mine. Considering the ground that was covered during the last GANA
annual meeting February 4 - 6, 2014, can a case be made to re-think that
situation if you’re a glazing subcontractor? Here’s a look at some of
what was covered.
Much of the focus of the recent “battle for the wall” victory came out
of the GANA Energy Division, with Tom Culp of Birch Point Consulting leading
the presentations at the ASHRAE meetings. With help of the glass manufacturers
who are part of the GANA Flat Glass Division, the proposed amendments
were voted down at the ASHRAE board level by a 20 – 1 margin. That effort
had a lot of contributions made by many people inside and outside the
glazing industry, but the technical effort had a lot of push from GANA.
"The stimulating ideas from
a design and execution standpoint were staggering, all of which BEC subcontractors
can use when they call on their architect customers to assist with design
Even with all the good of this victory, our industry still
must adapt to changing realities. For example, life cycle analysis (LCA)
is getting closer to becoming something we have to deal with, just as
we now have to address structural performance and air and water resistance.
The GANA Energy Committee is attempting to set the standards for the product
category rules by which individual products will be measured against each
other, leveling the table so that concise and accurate comparisons can
be made. Some manufacturers are doing a lot with this now for their products.
LCA will trickle to the glazing subs, as part of it includes how much
energy a product takes to perform over its expected service life, and
how much energy it takes to recycle it at the end of that time. Glazing
subcontractors will have to be conversant in this language to be able
to explain it to their customers.
A leading national architecture firm has already developed in-house standards
for determining which products to use on its projects. For instance, in
comparing a precast concrete and punched opening window to full glass
and aluminum curtainwall, the total glass curtainwall came out a poor
second. It takes considerably more energy to produce aluminum—from the
quarry to the extrusion press—than it does to make concrete. The basis
for the firm’s decision came down to the cost per square foot of the energy
required to get the opening on the building. “Battle for the Wall II”
might be forming in this arena.
As designs and products get more sophisticated, architects can design
with glass and still meet energy goals. This was shown at the GANA annual
meeting, in which presentations from universities focused on how to address
and improve thermal performance of curtainwalls, especially glass. Another
presenter talked about how the location of punched windows in relation
to their surround can affect their thermal performance by as much as 10
– 15 percent. He noted that moving a window back from the outside surface
even as much as 2 inches can reduce the energy footprint of the building.
Another example of improvements in glazing efficiency discussed that European
designs are now incorporating operable panels in glass mullion system
installations to aid in ventilating lobby spaces. Options included:
• Operable screens, such as venetian blinds but with monolithic
panels that slide over windows outside, rather inside the building;
• Systems that change the orientation of the glass to the sun, creating
a visually stimulating saw tooth design for the plan of the curtainwall.
In this configuration, the staggered panel reduced the sun’s incident
angle on the glass, while the height of the stagger also created a shading
screen for the light next to it; and
• 3D spandrel panels with super insulation that act as shading devices.
The stimulating ideas from a design and execution standpoint were staggering,
all of which BEC subcontractors can use when they call on their architect
customers to assist with design issues.
Another high point was Jim Benney’s presentation about trying to modify
the NFRC’s computer modeling approach (CMA) for certifying exterior, vision
glass curtainwalls to accept spandrel, pattern frit, or translucent interlayers.
He showed how complicated it can be to determine actual performance of
these types of glazing within the confines of the NFRC certification process.
The conference also had several laminated glass topics that will eventually
reach the BEC glazing subcontractors. One, in the Laminating Division,
centered on the use of laminated glass in doors, and if and how the interlayer
compresses when hardware (pivots, push pulls, etc.) are attached, and
if there’s any visual distortion when it is compressed. Another topic
in that division dealt with how glass strength changes when laminating
different thicknesses. The group also covered weathering testing of laminated
glass; presently, there is no standard for weathering. For example, standards
do not exist for all the glass in canopies or similar installations with
exposed edges, regarding the duration or attributes laminated glass should
have after prolonged exposure, such as delamination or separation at edges,
All of these points might eventually affect how glass handrails are designed,
fabricated and installed. Given the number of glass handrail failures
over the last couple of years, the Canadian code authorities currently
are developing a standard that will be balloted this year. That code may
require wind tunnel and impact-resistant testing, monitoring frequency
after installation and what to look for when inspecting, as wells as certification
for handrail installers.
When asked what they wanted most for the exterior envelope, the Energy
Day participants’ main wish was for performance-based, rather than prescriptive
codes. GANA, across the board, is trying to help lead the industry there
throughout all the divisions.
The Insulating Glass division is going to look at whether insulating glass
requires framing members to support all edges, or if butt-jointed glazing
will be permissible. There have been numerous requests from the architectural
community to design insulating glass without frames on two edges, doing
away with either verticals or horizontals. If the horizontals are deleted,
the discussion then becomes how to support the dead load, and more specifically,
can the glass be supported on setting blocks located at or immediately
adjacent to corners. These two issues are going to be reviewed in conjunction
with the Insulating Glass Manufacturers Alliance.
Most of what’s covered in GANA divisions other than BEC eventually makes
its way there in the form of projects bid, sold, and installed. As a result,
BEC members have a vested interest in being involved in GANA’s other divisions.
Currently, these other divisions operate without any direct input from
those within BEC. Granted, the manufacturers who predominate the membership
in these other committees might indirectly take back to the GANA division
level concerns which their customers voice (BEC members or not). But,
that’s not a given, and their take is going to be from their own perspective,
not necessarily the same as that of the BEC member. GANA glazing and sealant
manuals are referenced all the time in specifications, but so are some
of the other resources GANA is producing, including the many Glazing Information
Chuck Knickerbocker is the curtainwall manager for
Technical Glass Products (TGP). He is the chair of the Glass Association
of North America Building Envelope Contractors Division Technical Committee.
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