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 out,” 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?”

Task Groups Make Progress

Yesterday, the task groups were hard at work. The Glazing Guidelines task group made quick work of approving a number of edits to the section of TM 3000, North American Glazing Guidelines for Sealed Insulating Glass for Commercial and Residential Use, on the appropriate height of setting blocks for residential windows to keep them dry. The group approved sending the document to the Technical Services committee for balloting and, possible, approval.

The task group continued its discussion on its joint work with the Glass Association of North America (GANA) about capillary tubes. Since the last meeting the group has requested and received information from Guardian Industries about a proprietary software program the manufacturer uses to determine whether capillary tubes should be used. Guardian provided the group with information on “changes in pressure, temperature, volume and width to height ratio of sealed IG units on stresses,” which will be incorporated into the guidelines eventually.

The Gas Permeability task group met next with a bit more work ahead of it. At its last meeting, the task group agreed to end the gas permeability tests being run by CAN-BEST.

“A big challenge CAN-BEST had was the amount of argon coming through was so small it was actually lost in baseline noise and couldn’t be resolved,” explained task group chair John Greenzweig of HB Fuller.

At its last meeting the group put together a list of future actions with an eye toward revamping the research project at the heart of its scope. Today they discussed whether or not there was a way to set up an effective test unit that was an edge-sealed assembly section. Other ways to reduce costs of the project were also reviewed. Finally, Greenzweig took a straw poll to determine how much interest remained in pursuing this research.

“Is it valuable trying to continue looking at … edge seal assemblies … Or say we don’t think it can be done and move on?” he asked.

A show of hands from the group indicated that there was interest in pursuing research, but testing a full IG unit. From there, the group agreed to re-draft its initial request for proposal and has two new laboratories to which to send it, thanks to member suggestions.

The IGMA annual meeting continues through Friday.

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