IGMA Debates Visual Quality of IGUs
By Megan Headley
The Insulating Glass Manufacturers Alliance (IGMA) visual quality
working group discussed comments and intended to clear up its guidelines
on visual quality of insulating glass units (IGUs) as IGMA opened
its meeting today in Tampa, Fla.
In particular, the working group addressed comments that parts of
section 4 of the document are too stringent. The section on conformance
requirements lists visual obstructions that should not be allowed
in an IGU including: adhesive residue, dessicant dusting, dirt/debris,
fingerprints, fogging, suction/vacuum cup marks and water/cleaner
spots. The document also states that marks on the flat glass used
in the IGU should comply with ASTM C10-36 and sightline infringement
shall be no greater than 1/8 inch along any sightline of the IGU.
"When you put out a document that says 'not allowed'
my concern is that we're going to be rejecting product that's perfectly
sellable," said Jeff Haberer of Cardinal Glass Industries.
"We're mandating perfection, and I think we need to scale it
"In order to be practical, you have to allow certain imperfections,"
added Bill Hammon. "Minimizing is the key word."
Following discussion on what constitutes a visual obstruction and
concerns of overstepping other documents on similar topics, including
ASTM C10-36, the group agreed that many of these items should in
fact be quantified. The group agreed only two items, fogging and
suction/vacuum cup marks, should not be allowed in the document.
Several group members commented that the type and quality of the
lighting can impact the visibility of an obstruction.
Chris Barry of Pilkington suggested the document state that standard
lighting conditions be used to determine the visibility of an obstruction.
Bruce Virelson of PRC Desoto International reminded the group that
fog is sensitive to lighting. "There have got to be some sort
of comments in there on lighting," said Virelson.
However, others noted that lighting conditions can't necessarily
be controlled in the field.
"If you're getting very prescriptive with the lighting, how
are you going to meet that in the field?" asked Tracy Rogers
The working group is now reviewing these comments.
The IGMA meeting continues through Saturday at the Renaissance Hotel
Tampa International Plaza.
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