Volume 48, Issue 11- November 2013

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.

Nobody wins.

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 of infiltration.

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.

Follow directions.
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.

Constant maintenance.
Improvement in unit construction will promote a longer IG life.


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