TWINDOW STORY

A Story About Natatorium Windows

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A long time ago in a simpler time, I was working for a firm that was designing a huge high school (for the time). I wasn’t part of the design team because I was busy with lots of small stuff as the junior firm member. The design team was the boss, two of his classmates from college, and a ‘retired’ architect, who once had his own firm.

The high school was all masonry. Brick and block exterior walls. Even many of the corridor wall were brick. One of the special things about the school was a natatorium. There probably weren’t five natatoriums in the greater Cincinnati area at the time, and most of those were YMCA facilities.

Of course, all of that moisture INSIDE the building was a major concern. Everyone was tuned-in to the potential problems. Sweating windows were a concern. Insulating glass was a recent innovation, but looked like a solution. If only you could find insulating glass that had a seal that was up to the task.

The boss found the solution - a new product by PPG, PPG Twindow - Glass Edge insulating glass with ‘permanent’ seal, and a 20 yr warranty. Unlike modern insulating glass, the two panes of glass were joined by glass ‘welded’ to the panes to make the seal. It was a great product, but ultimately too expensive when sealants became more reliable.

One tiny issue was that you had to use a standard size, unless you ordered more than 500 pieces. We needed 15.

On the plus side, there were 67 standard sizes.

All you had to do was pick one of the standard sizes of glass and use a window framing system that allowed for a little tolerance. Easy peasy, right?
I should mention that these were the days before calculators. And the glass sizes we had to choose from were all in whole and fractional inches, e.g, 34 3/16".

I should also mention that the school design had advanced to the point that we knew exactly what the three window run openings measured. Two were identical. The masonry structure interrupted the window runs, so the center run was different than the end runs.

The ‘retired’ architect spent a week doing trial and error calculations with pencil and paper. Every time he felt lucky, a math error popped up to rain out the victory dance. 

After that week, I got the job.

It really was a nasty piece of work.
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You will be pleased to know that we solved the arithmetic problem. The ‘gimmick’ I found was using different glass sizes for the two different glass openings. 
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Lesson Learned
The lesson learned (by me at least) is find out about what you are not familiar with early in the project. In DDs the dimensions of the natatorium window runs could have been anything we needed them to be.