IGMA Members Hear Tips For Successful IG Testing
March 24, 2011
LAS VEGAS - Dan Braun of Architectural Testing Inc. opened this morning's session of the Insulating Glass Manufacturers Alliance’s (IGMA) annual meeting, which is taking place this week at the Paris Las Vegas, with tips for successfully testing insulating glass (IG) units. Braun walked attendees through common failures in IG testing, including handling, chemical/volatile fog, gas fill and seal durability.
When it comes to handling, Braun pointed out that each lite is handled about 15 times or more during testing, "significantly more than your typical production unit," he said, "so I think it makes good sense to give some attention to handling."
He offered quality control suggestions for IG manufacturers, including inspecting glass edge conditions, polishing the glass edges and, of course, protecting the samples during shipping and handling.
Next Braun addressed fog testing.
"One of the tough parts about the fog test is if the fog test fails the whole test fails," he began before discussing "the controversy" with the fog test. "With the implementation of the harmonized standard in 2002, the test has become more severe," Braun explained. The change has resulted in more failures and lots of discussion. "I think the argument in the industry is fog failures are not a big warranty issue so why do we have a test that does not accurately reflect real world conditions? Perhaps a good point," Braun said. He countered, "My experience is it's out there, you will see it, but it's not grossly visible so every consumer will look at it and say it’s objectionable."
He said one discussed solution has been ranking failures and deciding what is acceptable.
A more recent change to the ASTM test procedure for fog testing now controls the light source used to check for fog, making the test less subjective.
"That was addressed in the 2010 version of the standard that just came our," Braun said. "It's unreasonable to expect this will result in fewer fog failures; it's probably reasonable to assume this will result in more fog failures. Some of the labs that may have been more casual in looking for fog ... now have a consistent, repeatable viewing area."
In offering quality control tips for fog testing, Braun said that he has typically advised manufacturers to complete the fog testing before weather cycling, noting that it seemed like a commonsense solution to determine whether the one-week test will be successful before spending the time and money on a 15-week test. However, he said he was recently told that waiting and allowing for the linger-cure times might be beneficial--a suggestion he's hoping to test in the future.
On argon gas testing, Braun suggested that manufacturers consider the impact of grids and spacers. He noted you'd normally just have grids and spacers in fog test samples, but to keep in mind these components can result in dilution of gas mixture and should be considered. He also advised recognizing the limited accuracy in testing low-fill-level argon units.
When it comes to seal durability, Braun said, "There is a certain number of failures that we see occur from corrosion to the low-E coating so, to me, the answer seems pretty obvious that there should be some consideration to edge deletion."
He said he hears similar arguments as with fog testing: these failures don't occur in the field, why do they occur in the test? He admitted there's not a perfect answer, noting, "It's unlike the real world where if you have an ideally glazed channel, let's face it, it should be fine." But, he commented, test conditions are worst-case scenarios. "If you can make it past the test you're certainly going to limit your callbacks in the field."
Braun concluded by reminding his audience that these issues will only become more important in the future. "This whole arena of thermal performance is getting increased attention from the Department of Energy," Braun said, "so it's a matter of do you want to be riding the horse or be pulled along?"
The IGMA annual meeting continues through tomorrow, with, among other things, a joint meeting with the GANA Insulating Division being held as part of GANA's Glass Week.
Stay tuned to USGNN.com™ for updates from the conferences.