Thermal stress standard moves forward

By Katy Devlin, Glass Magazine
February 6, 2009
COMMERCIAL, RETAIL, FABRICATION : CODES & STANDARDS, MEETINGS AND EVENTS

During the second day of the Insulating Glass Manufacturers Alliance Annual Conference, Bill Lingnell, president of Lingnell Consulting Services, Rockwall, Texas, and technical consultant to IGMA, presented a progress report for ASTM E 2431, a standard to reduce thermal stress breakage. Lingnell has been leading a project to extend the standard that currently covers single-glazed units to include insulating glass.  The standard will provide glass companies with charts of the characteristics of thermal stress, outlining the factors that lead to thermal stress.

“Our objective was to take something difficult and complex and break it down,” Lingnell said.
The project team completed work on phase one, developing a research method to determine the conditions of thermal stress in insulating glass units.

“Developing the process to do this was the hardest part,” Lingnell said.

Work on phase two will begin this year as the team will develop a large number of charts that show the various conditions of thermal stress.

“The user would look at the chart to see which condition matches their project,” Lingnell said. “We want to make a standard that provides the majority of conditions. We know we can’t cover everything, but we hope to get a majority.”

Bob Spindler, director of product development for Cardinal IG, Minneapolis, said the standard, when completed for IG, would provide a great service to glass companies.

“Thermal stress is one of the most unknown characteristics of glass in the industry,” he said. “Most of the characteristics [of thermal stress] that glass manufacturers know about, we’ve learned through experience. … This work is very important to the industry, no question.”