Volume 35, Number 4, April 2000



Insulating Glass Performance

the industry should think about changing its data collection methods

by Werner Lichtenberger, P.Eng.

Like other building components, insulating glass has a finite working life directly determined by its construction and service environment. That’s why tracking insulating glass performance has been a top priority within the window industry.

Domestic organizations like the Sealed Insulating Glass Manufacturers Association (SIGMA), Sweden’s Monteringstekniska Kommitten (MTK), and Germany’s Ift Rosenheim (Institut fur Fenstertechnic), have conducted studies examining several performance-related issues, including failure rates. But such studies don’t always yield accurate data.


Measurement Issues

Researchers spend so much time defining measurement parameters and mechanics that often out-of-date information gets collected. For example, the sample population of SIGMA’s ongoing study includes components and designs that do not necessarily reflect typical residential windows. The recent PVC window and “warm-edge” seal boom has made data collection even trickier.

Since flaws usually don’t show up right away in new designs, studies should be looking at the performance of window products during the first five years of service. In addition, warranties can conceal performance issues, since windows are often replaced without addressing the root of the problem.

A major issue with current industry performance tracking is that data is presented without offering clear, concise advice or direction. This lack of positive action is clear when looking at proper glazing issues. To further cloud the issue, performance has been summarized with failure data excluded because the reason for failure was obvious—such as water in contact with the insulating glass seal.

Methodology is another concern. When analyzing insulating glass performance, re-searchers tend to compare failures to annual production figures without considering the age of the failed unit—a method that can lead to inaccuracies. Failures should be recorded by both year of manufacture and year of occurrence. These figures, combined with continuous production data, will produce an accurate failure rate.

In addition, analysis of more specific information, such as product line data, will help expose the root cause of failure. A quality auditing program that scrutinizes the manufacturing process using certain benchmarks is a valuable monitoring tool—and an effective addition to any training program. Unfortunately, auditing done by an outside party will not reflect day-to-day manufacturing process variations. For this reason, self- auditing by manufacturers is most effective.


Tracking Benefits

A solid performance-tracking program allows a facility to compare its performance to the performance of other plants. It encourages effective fiscal management, which is especially important when dealing with service life warranties. The program also provides a model for product quality improvement, allowing manufacturers to benchmark their performance versus other program participants. Additionally, the program serves as an effective complaint management system, and gives companies a marketing edge that other manufacturers may not enjoy. But the ultimate benefit of performance tracking is customer satisfaction, since prompt response to issues minimizes service costs.

And remember, failure rates should always be measured whether they are low or high. Qualified data proving low failure rates can be your most effective sales tool.


Copyright 2000 Key Communications, Inc. All rights reserved. No reproduction of any type without expressed written permission.