Presentations Take Place During IGMA Meeting
During the Insulating Glass Manufacturers Alliance's (IGMA) annual
meeting, which took place this week at the Hyatt Mission Bay in
San Diego, attendees were treated to a number of technical presentations.
Yesterday morning IGMA technical consultant Bill Lingnell of Lingnell
Consulting Services presented an update on his thermal stress research
pertaining to insulating glass (IG). "We need to understand
why you don't just jump from monolithic to IG," Lingnell opened.
|David Bailey of Bodycote Testing Group (left)
and Bruce Virnelson of PRC DeSoto International presented the
topic: "ASTM E 2190: Has the Bar Been Raised?"
According to his presentation, "There is a pre-stress in the
IG unit due solely to the temperature difference from outside to
inside without the influence of solar intensity." Lingnell
then added, "Even before you start putting sun on this, there
are some conditions that are happening."
After walking his listeners through the basics of thermal stress
considerations for monolithic glass-ranging from frame type and
size to interior and exterior building conditions-Lingnell proceeded
to walk through his analyses for addressing the differences that
IG gap has on thermal stress reactions.
While his research provides for "a numerical procedure
that shows the magnitude of thermal stress in IG," Lingnell
pointed out that this is simply the beginning of his research in
"We have some good examples here but that won't take us as
far as we want to go," he said. His goal is to continue his
research with a second phase that will entail creating "dozens
of thermal stress charts" to lead to a procedure for predicting
thermal stress in IG, and perhaps, down the road, a third phase
to address the curves thrown into the mix by the newer triple-glazed
|IGMA technical consultant Bill Lingnell presented
an update on his thermal stress research on insulating glass.
For Phase II, Lingnell said, "We've got the process, we know
it works, but we have to create these runs."
"We know how to design for wind load but we don't know how
to design for internal stress," commented Bob Spindler of Cardinal
from the audience. "I'm very excited about Bill and Lynn [Beason's]
research. It's the first time someone put together a program on
thermal stress and what the recommendations should be."
Next to take the floor yesterday was David Bailey of Bodycote Testing
Group and Bruce Virnelson of PRC DeSoto International. The pair
addressed ASTM E 2190, asking, "Has the Bar Been Raised?"
In providing some background on the various IG test methods in
use (ASTM E 773/E 774, CAN/CGSB 12.8 and the new ASTM E2190 endorsed
by IGMA and the Insulating Glass Certification Council), Bailey
happened to address a topic that had been much in discussion during
working group meetings earlier in the week: the volatile fog test.
While Bailey provided information on how his laboratory follows
the test methods, he did comment in regard to E2190, "I think
it would be to the industry's benefit and the laboratory's benefit
to have the light source and the distance and the angle to be very
|Jim Larsen of Cardinal IG presented
"Next Generations of the Energy Star Program: How Will
It Affect You."
Virnelson went further into comparing some of the differences in
between the tests, before providing several charts on failure rates
for each test method.
"As you make a sample long enough, you get better at making
it," he commented in explaining trends. He summarized that
while it should be more difficult to get units through the newer
method's way of testing for volatile fog and weathering, "the
data seems to suggest
might be a little bit more difficult
in the fog
not a lot more difficult in the durability."
However, he added, "It is too early to tell."
Next up, Jim Larsen of Cardinal IG presented a talk on the next
generations of the Energy Star program (CLICK
HERE for related story). Larsen explained of the reasoning for
the revisions that the Department of Energy is "thinking Energy
Star doesn't differentiate itself enough from the codes." However,
he expressed concern that once Energy Star raises it's bar, so to
speak, the model codes would follow.
"Is this really going to improve energy efficiency?"
he asked as he walked his audience through the revised climate zone
maps and compliance examples showing that in some areas there aren't
products available to meet the requirements.
HERE to read more about IGMA's 2009 annual meeting.
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