(*Chip Merlin’s Note: A fascinating aspect of our work is learning about many different things that have nothing to do with the law. We have to understand construction, restoration and building repair to be effective for our clients. Our guest bloggers from TSSA Storm Safe know more about glass windows, doors and glazing than anybody that I have ever met. Their two hour lecture to my law firm was eye-opening. While it may seem weird to some that this topic can be so important, we routinely represent clients whose buildings have tens of millions of dollars at stake in litigation regarding glass windows and doors. This discussion is very timely given the disagreements of wind damage caused by Hurricane Ike.)
I am going to ask you to take a moment to look at a structure; it could be your home or the office building where you carve out a living. In essence, it is one big puzzle constructed out of concrete, steel, wood, rebar, aluminum and, last but not least, glass.
During the construction process, engineers, architects, contractors, municipal building officials and everyone else get together and argue a lot until finally everyone agrees that the process is complete. The whole crew steps back and admires this shiny new structure, the city welcomes the tenant with a CO and the insurance company binds the structure with a policy. Prosperity ensues until Mother Nature decides to pay a visit and changes things. John Lennon must have been thinking about these types of events when he wrote, “life is what happens while you’re busy making other plans.”
Cyclical wind pressure mercilessly batters the structural integrity of the aforementioned ”puzzle” building for countless hours with accelerated bursts of negative and positive pressure from different directions. These forces are very damaging to any building. Well engineered roofing systems suffer dramatic uplift damaged, to the point that they are ineffective and need to be repaired or totally replaced. Concrete walls crack like paper and spalling becomes evident, even interior walls and floors suffer great damage. With all this terrible devastation, how is it the windows and other glazing systems mysteriously never receive damage? The truth of the matter is that the same force that affects roofs systems and concrete naturally affects the glazing systems as well.
From a design perspective, a window is not just a piece of glass; it is a complete system that balances out the design pressure from the masonry, thru the MO (Masonry Opening), to the other side of the masonry. These assemblies contain many complex parts that, as a total system, are tested to withstand a predetermined pressure and wind force rating. Yes, even older window systems had to pass testing protocols. These systems, new and old alike, if exposed to a high velocity wind storm event should be investigated and analyzed from an engineering prospective to determine what damage profile exists currently and if they will be effective protection against another prolonged wind storm event. Remember, a glazing system is not just a piece of glass! These sliding glass doors, windows, and commercial store front systems have specific screw fields with calculated embedment protocols, primary and secondary seals with engineered approved sealants, aluminum (or other material) frames members and engineered mull bars. All these components damage in particular ways when acted upon by negative and positive pressure and other effects due to a windstorm event
Recent storm events like Wilma, Katrina, and Ike were responsible for property damage into the billions of dollars, and with a strong effort, professional advocates have done a great job seeing to the repair of roof damage and other envelope of protection remedies. If the glazing systems have not received the same consideration, those buildings may still be sitting with dramatic fractures in the exterior envelop of protection. These issues, if not properly assessed and remedied, may be the cause for extensive damage in the chance of a future windstorm event.
Keep in mind that sliding glass doors, windows, curtain walls, and commercial store front systems are much more than a way for you to look outside and admire the sunshine. So next time you look thru one, realize that it is much more than a simple window to the world, it is in fact a complex piece of the entire construction puzzle which makes up your structure.
Steven Browner
Ivan Browner
Jeff Dobbins
TSSA Storm Safe, Inc.
