If Only They Knew …
By John Hollis
Imagine this scenario:
It’s been just a few short years since the building’s completion when
the owner suddenly notices a clouded effect in between the lites of a
dual pane insulating glass (IG) unit.
Worse yet, he doesn’t discover the mold that has developed
until much later.
Imagine his angst, knowing that the problem is going to
cost him a bundle in repairs and untold headaches in trying to get the
responsible party to step forward. It will, inevitably, leave a bad taste
in the mouths of everybody involved, from the angry and very frustrated
owner to the contract glazier, the fabricator and the architect who first
designed the building.
But there is help. Here’s a look at ten tips, based on input
provided by Margaret Webb, executive director of the Insulating Glass
Manufacturers Alliance (IGMA), to help avert any such disastrous IG failures
in the future.
Ten Top Ways to Avoid an IG Failure
Keep it dry.
Proper drainage of the draining channel is a key element to maximizing
the life of an IGU. Prolonged exposure to water or saturated water vapor
in a glazing channel is the number-one cause of seal failure in IGUs.
Let it all out. Design a glazing system with proper
drainage. Glazing systems must be designed with a means of completely
draining infiltrated water at a rate equal to or greater than the rate
Have a back-up plan. Have a back-up plan ready to
deal with moisture. It’s a good idea to think about setting blocks that
would allow for an area of possible water accumulation in the sash or
frame. The water can flow easily to and out the weep or vent holes. (You’re
probably getting the idea by now that water accumulation is bad.)
In the clear.
Maintain proper clearance between the framing system, the face of the
glass and the edges of the glass. The face of an IG unit should be cushioned
from the adjoining framing system with glazing gaskets, sealants, spacers
or tapes, and all of the materials should be thick enough to maintain
proper clearance from the framing system, the face of the glass and the
edge of the glass to prevent breakage from stress.
Out with the old.
Be diligent during building remodeling to make sure the building’s frames
and the new IG units are always compatible.
Don’t stop learning.
Keep yourself up-to-date with improving glazing systems, manufacturing
techniques and overall performance criteria of IG units. Technological
improvements have been steady over the last 25 to 30 years, reducing the
number of IG failures. It is imperative to remain knowledgeable about
the latest industry developments.
You have guidelines for a reason.
Follow the published guidelines provided by IGMA, North American Glazing
Guidelines for Sealed Insulating Glass Units for Commercial and Residential
Use. The organization’s mission is to harmonize industry standards and
raise the bar on quality by ridding the specification community of non-certified
and un-tested insulating glass units.
Just as in number 7, follow the minimum sealant dimensions for insulating
glass assembly as referenced in the IGMA technical bulletin TB-1201-89(05),
Sealant Manufacturers Minimum Sealant Dimensions and Placement Survey.
Quality, quality, quality.
Incorporate a quality assurance program that will assure the long-term
durability of insulating glass performance. IGMA’s quality assurance program
is based on its technical manual, TM-4000-02, Insulating Glass Manufacturing
Quality Procedures Manual, which contains 16 of the 20 elements required
for ISO 9000 certification. IG manufacturers are required to maintain
a properly documented assurance program, listing corrective actions on
all components of their IG unit construction, including glass, spacer
and sealant systems, among other things.
Improvement in unit construction will promote a longer IG life.
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No reproduction of any type without expressed written permission.