• Field Notes 26.09.2012

    Chicago has always been one of my favorite cities. With sons living there, I jumped all over the chance to attend the GANA Fall Conference there this past week. I flew in Sunday morning after the arrival of grandchild number eight on Saturday. I then visited the Frank Lloyd Wright Robie House (arguably his best work), the Art Institute for the Japanese print collection (some of which were from Wright’s collection), and watched the Eagles pull out a gift from the Ravens at the very last minute (we will NOT dwell on what happened in Arizona this past Sunday). I also had a first-time-in-30-years reunion with four friends who helped me survive college. Good times, no doubt. But then there was work to do.

    While I only got to attend the Technical Committee on Tuesday, there were several notable discussions. One of the discussions was on secondary seal migration into the vision area of insulating glass units. It seems this is becoming more of an issue. An industry consultant is asking if GANA is going to step into and / or come up with a standard to address this.

    Such sealant visibility is unacceptable and hasn’t been seen in the industry before. The root cause would seem to be too much sealant applied to the spacer during unit fabrication, which then gets squeezed past the spacer into the vision area when the glass is set to the spacer. However, that’s not the only issue; over time the sealant is moving for unknown reasons, almost like it’s “bleeding” into the vision areas. The cause of such “migration” is unknown. GANA is developing guidelines for this – what’s acceptable, what’s not, etc. This issue is also getting the attention of the Insulating Division within GANA. The organization is calling this problem “PIB Migration,” so you might see that phrase more in the coming months.

    Building Commissioning is another issue you might start hearing rumblings about. When I was doing work a couple of years ago regarding housing and energy performance, some of the Energy Star ratings had started to talk about full-building commissioning. One topic was how tight a home could be for air infiltration, and that the home had to be fully tested. Basically, what it amounted to was pressurizing the inside the house to see how tight it was. So, any of the penetrations through the walls, (doors, windows, bathroom and kitchen vents, etc.) were tested as a whole.

    For anyone who has tested windows and curtain walls, you know how rigorous the tests are for individual products. Now multiply that to a whole building. In commercial construction, it’s virtually impossible to test a whole building for air penetration. For example, can you imagine what the blowers needed for a three-story building to build up enough pressure, and then how would you measure the pressure drop? I guess it would sort of be like the window air test, but on a much grander scale.

    Tom Culp reported ASHRAE 189.1 was being developed to try to address this issue for the whole building envelope. As I’ve said in the past, I’d love to see how the air and water tests typically required of windows and curtain walls would be applied to other parts of the envelope. You see some of that tested at mockups occasionally, when surrounding conditions are included (such as precast, brick or stud wall construction, etc.). Now apply that to a larger scale. What’s the last job you worked on where you could or would test the whole building? How would that even be accomplished? Who’s set up to conduct that sort of test?

    Fortunately, the voice of reason broke out and several people raised concerns with how much whole building testing would cost and what the liabilities would be. ASHRAE may not move off the whole building testing, but they’re still interested in having observation and inspection of the building envelope during construction, as well as on-site testing to confirm compliance with whatever standard may hold sway. For the glass  and the glazing industry, with the way specifications are written, there’s enough industry self-governance through the ASTM and AAMA testing requirements to ensure through initial mockup and jobsite testing the specifications can  and are being met.

    I think our industry has done its part, at least in commercial construction, to cover all the bases here.  Whether or not the surrounding trades or other construction detailing has to change, it will be interesting to watch.  That may impact the glazing industry, because detailing to different air and water barriers on those surrounding conditions upon which the windows and curtain wall are mounted is 90 percent of the detailing required.

    No further discussion about turtle testing came up, which was something new since the last time the Technical Committee met.  But as always, something new always comes up.  It’s certainly interesting.  And like Chicago itself, it’s what keeps me coming back to these conferences, along with a chance to catch up with old (in Greg Carney’s case, VERY old) friends.

    Posted by Bryan @ 11:25 am

  • One Response

    • Thanks for the mention Chuck! It always makes me happy to know that at your age, you still remember my name. Always great to see you my friend. Next time I want to go on the Wright tour with you.

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