Patrick Loughran, Goettsch Partners, has authored a book on problems with glass constructions, and he shared some of his insights with fellow architects at the American Institute of Architects (AIA) convention in Los Angeles earlier this year.
To a standing room only audience, Loughran pointed out that he was discussing these problems which have occurred so that they don’t get repeated. He said there are nine things to look out for to avoid building enclosure problems.

1. Number one on his list was nickel sulfide stones in tempered glass. “They can cause spontaneous breakage,” he told the group, adding that this was a rare occurrence. He cited the example of Waterloo Station in London, where the problem had occurred.
   
2. Next on his list was thermal stress. “This happens especially at the edges,” he said. Examples where this has been a problem included the CNA Building in Chicago and the Bacardi office building in Mexico City.
   
3. Number three was corrosion. “Most people don’t think of glass as corroding,” he explained, “but with the more transparent style of design you get corrosion from other building materials, such as cement and the metal.” He advised that the problem can be prevented by simply cleaning the glass.
   
   He used the Louvre Museum in Paris as an example where corrosion had occurred, and said that architects have to think about how their designs are going to be cleaned.
   
4. Incompatibility of materials was his fourth area. The Louvre was cited again as an example where the PVB interlayer and the silicone sealant had proven problematic. He said the four-sided silicone glazing has had some discoloration where the material came in contact.
   
5. Next problem—leakage. “Do tests with a mock-up,” he advised. “Our design is two dimensional,” he pointed out, “while the installation is three dimensional. Testing can be used to bridge the two.” He also added that testing gives confidence that a building won’t have leaks.
   
6. Perhaps surprisingly, energy was number six on his list. “In the quest to save energy, we can’t make the system too complex for users,” he explained. He gave the example of double-wall facades where the desire for energy efficiency has led to lack of use because they were too complex.
   
7. “Today, glass is being used more as part of the structure rather than just as a window,” he told the audience in introducing structure as problem number seven. As an example he cited the Palais de Justice in Bordeaux, which has a large glass wall that originally had glass fins but they are being replaced with metal. “They’ve lost confidence in the design,” he said. Size glass properly, he advised.
   
8. Number eight on his problem list was redundancy. “You have to have a design so that if a lite of glass breaks then it doesn’t cause another lite of glass to break,” he said. 
   
   This happened at the Guggenheim Museum in Bilbao, he reported. “There is a large glass wall on the interior that is curved slightly. Early on, one of the higher lites broke and that caused other lites to break,” he said. Metal clips were put on the lites to prevent this from happening again, he reported.
   
9. The final problem on his list was impact. “Whether from natural events like wind or blast resistance for security, building enclosures are vulnerable to a variety of unwanted attackers,” he said. “Glass walls can be designed to resist impact from bullets to baseballs to bombs,” he pointed out. “Glass will break,” he said. “What architects have to do is make designs so that you don’t end up with broken glass on the floor.”

USG
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