by Dez Farnady
It has been nearly five years since USGlass magazine published my prognostications in an article titled, The Impending IG Crisis. I should have known that the business of predicting the future has at least one major drawback: You can look foolish if you hang around long enough to find out your fortune-telling did not come true. My comments in 1995 suggested there would be a major crisis because of a dramatic increase in the number of residential insulating glass failures.
And here I am today having lunch on my own words. But I am not taking everything back. The good news is things move a lot slower in this world than we fortune-tellers think. So, even if I was right, we are moving so slowly that I will be long gone before we get there. There may not be an insulating glass crisis, but buck-up insulators, because units are continuing to failjust not at the rate I anticipated.
The American consumer has been conditioned to accept planned obsolescence in so many products that he no longer concerns himself with distinguishing among the things that are designed with a limited life span and things that go out of fashion or just get used up. We all know carpets go out of style as well as wear out; roofs wear out and need replacement. All we had to do is wait a few years for the marketplace to adjust the perception from the permanence of monolithic glass to the limited life of an insulating unit. Insulating glass is no longer expected to last a lifetime. Homeowners have begun to include IG in the replacement cycle that affects most components of the modern home.
Insulating units continue to fail for the same reasons they have been failing all along. Adverse glazing conditions or installation problems, design problems or under designed glass and intense weather conditions still contribute to reducing the life-span of the seal. But an interesting phenomenon seems to be taking place.
Although there are more insulators today capable of supplying Class A, dual-sealed units, the butyl unit fabricators seem to be taking control of the market. Butyl is one of the best moisture seal available for this application, even though its structural capacity used to be questionable, particularly in some warmer climates. The best units in the business have always been made with a primary seal of polyisobutelene and a secondary structural seal of silicone or polysulfide. Price, availability, ease of use and improved structural stability, have made single-seal hot melt butyl popular. Butyl units dominate the western market to the point that some fabricators offering dual-sealed units also offer single-seal butyl units. These units are ideal for the residential market with its requirements for fast turn around, unusual shapes and grid units.
Although I may have been wrong about the crisis, I have not changed my mind about the quality standards. My personal preference is for a dual-sealed silicone unit first, with a primary moisture seal of polyisobutelene (butyl) and a secondary structural seal of polysulfide. The third choice of single-seal butyl is not a bad one for most residential applications.
I also have not changed my opinion about the need for the maximum amount of desiccant use possible. Warm edge and superspacer-type products have brought with them the solid tape type desiccants as opposed to the traditional silica granules that had been pouring into the spacer for decades. These desiccants, by their nature, wrap around the unit as if the unit was filled with silica gel on all four sides. Since four sides filled have twice the moisture-absorption capacity in a square frame as two sides filled, the desiccant tape on four sides insures the maximum possible absorbency.
This theory is void if these desiccant tapes do not perform as well as the silica gel. I have not done the research and only hope that the new technology is as good or better than the old, because only then is it a real step forward. These new spacer technologies, along with better educated customers, have reduced the publics demand for the low profile spacers slightly. Low profile spacers reduces both sealant and desiccant quantity.
The economics of the marketplace have reduced our problems by stabilizing the source of supply. The business of providing the insulating market with new, retrofit and replacement units is so competitive that irresponsible fabricators (who may have been hand-shooting silicone units in their garages) seem to have disappeared. Even small established insulating glass fabricators are working on tight margins in highly competitive markets, where you are only as good as your last unit and your lead time. Everyone seems to be working hard in order to be able to stay in the IG business for the long haul.
While the best unit may give you 20 years or more, even the least expensive one can give you ten years or more, under the right circumstances. And while the less expensive units are providing better performance and longer life, consumers are beginning to understand price, quality, warranty and durability differences.
Another interesting development that will take some of the pressure off insulating glass in some difficult glazing situations is the increased use of monolithic glass, particularly in applications where heat gain, not heat loss, is the primary energy problem. For many years, heat loss was the only energy concern in the residential market. Commercial construction continued to use monolithic heat reducing glass because large glass surfaces create major heat gain and air conditioning costs. Heat gain issues in the residential market were difficult to deal with because the public perception was that insulating glass solved both heat loss and heat gain problems. The residential market has been reluctant to use glass products that had some color. Everything has to be more color neutral to keep the decorators happy.
There seems to be a transition from using hard-coat low-E glass for heat reduction to using the even more color-neutral, all purpose, soft-coat, low-E coatings. The soft-coat products, now readily available, are capable of generating a high U-value as well as good shading coefficients while providing very high visible light transmissions. The transition seems to have created a gap that has allowed for the return of some monolithic energy performance products to meet heat reduction requirements. A perfect example is the replacement of failed insulating glass in overhead glazing with tinted or second surface reflective laminated glass. I have replaced several large skylights where continuing re-glaze efforts discouraged the owners to the point where they were willing to accept a monolithic product. They were surprised with the performance and happy with the assurance that no further failed unit replacements were going to be necessary.
The knowledgeable consumer is no longer blind to air conditioning costs. The one-sided U-value concern that started the big push for insulating glass has evolved into a more sophisticated energy consciousness. There is more room for ways to conserve energy than just with air spaced glass.
In the attempt to re-establish my reputation as a fortune-teller, I believe there will be a push for exploring the new options offered by the myriad of new products carefully developed by glass manufacturers. The number of possible combinations with new energy-performance glass products, with and without air space, is already literally in the thousands. The aesthetic options have also multiplied a hundred-fold with off-the-shelf commodity products. Imagine the added options available when you combine all this with multi-layered laminated. These will truly make an ancient material like glass, fresh, new and exciting for the 21st century.
Dez Farnady is manager of architectural products for ACI Distribution in Santa Clara, CA.
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