“There needs to be some kind of guidance around the assembly,” Ruark said. The group’s members talked about the fact that distortion often occurs when “you start stacking multiple layers of glass.”
Members also noted this is a problem in both residential and commercial applications.
“We [the industry] are now entering the triple-pane market and it’s going to get worse,” said Bill Deuschle, vice president of external affairs at Traco in Cranberry Township, Pa. “I’m not an expert on glass but somewhere we need to tighten up the tolerances.”
“There needs to be some guidance around the assembly,” noted another AAMA member.
The group decided that it should collaborate with the Glass Association of North America (GANA) of Topeka, Kan., and the Insulating Glass Manufacturers Alliance (IGMA) of Ottawa, Ontario, on this issue. The group’s initial ideas included development of a white paper, educational piece or development of a standard. It noted, however, that GANA does have a white paper on the topic available.
GANA supports continued analysis and measurement of distortion in heat-treated glass, Urmilla Jokhu-Sowell, technical director of GANA, told USGNN.com™ in an interview today. In 2008, the GANA Laminating Division republished its glass informational bulletin (GIB) Design Considerations for Laminated Glazing Applications, which discusses optical distortion and other aspects that design professionals and building owners should be aware of when selecting and specifying laminated glazing constructions.
GANA’s Tempering Division currently is working on a GIB titled Methods of Measuring Distortion in Heat-Treated Flat Architectural Glass, Jokhu-Sowell says. “This GIB focuses on the different methodologies and instrumentations used for evaluating distortion,” she says. “GANA’s Standard Test Method for In-Plant Measurement of Roll Wave in Heat-Treated Architectural Glass (TD 100) served as a widely adopted industry standard prior to ASTM standard ASTM C 1651- Standard Test Method for Measurement of Roll Wave Optical Distortion in Heat-Treated Flat Glass, which is the current standard adopted by GANA’s membership.”
These documents can be found on GANA’s TechCENTER.
“Distortion in heat-treated glass continues to be a topic of interest for GANA’s membership and we expect our technical activities to continue work on its analysis and measurement,” Jokhu-Sowell says.
The AAMA task group decided to propose the formation of a joint task group among AAMA, GANA and IGMA members to develop an industry standard for visual quality of insulating glass in multilayered units. That proposal was set to be proposed to the AAMA board today.