After our experience with Hurricane Matthew, many on the east coast were relieved at the end of the 2016 hurricane season. Matthew was primarily a water event as opposed to a wind event, but nevertheless, uncertainty forced homeowners and businesses to invest thousands upon thousands of hours installing plywood covers, storm panels, and other types of shutters to protect their homes. Others may have been a bit more relaxed since they had impact resistant windows and doors in their home and did not need to install covers.
As often happens after a storm passes through, my phone starts ringing with inquiries about the pros and cons of various window and shutter systems. The inquiries are not surprising, but the amount of misinformation is, and I suspect this may be the result of aggressive marketing efforts that spur unrealistic consumer expectations and a general misunderstanding performance capabilities.
If you live in a hurricane region, all one needs to do is check out a week’s worth of mailers, what most of us consider junk mail, and I suspect that among them you’ll find at least one with a group of advertisements from contractors selling replacement windows. A common theme in these advertisements is the phrase “hurricane windows” or worse, “shatterproof hurricane windows.” Time for a reality check.
Windows that are tested for impact resistance undergo a battery of laboratory tests. The purpose of the impact testing is to assure that the glass will not blow out of the window because if it does, this results in an opening that allows the hurricane winds to enter inside the home.
Impact resistance testing starts with one very basic element; a 2” x 4” piece of lumber is fired directly at the glass from an air cannon at a high rate of speed. Results? Glass breaks! After the glass breaks, the laboratory then applies hurricane wind pressures, and the broken glass needs to remain in place in the window. At the end of the testing, the glass may be destroyed and will need to be replaced, but it has not blown out of the window.
Repeatedly, callers are astonished to hear that the glass can break. But that’s the reality. A reality that must be considered when deciding which products to use when protecting your home. A window that is rated as “impact resistant” does not mean that the glass is unbreakable. And once the storm has passed, you’ll need to replace the broken glass, the cost of which can be rather significant.
Building codes in hurricane prone regions generally require that exterior windows and doors be certified as impact resistant or that impact resistant shutters/covers be provided over the windows and doors. Impact resistant windows are a very important part of the construction industry and homeowners are well advised to consider their use. But, owners must also recognize that impact “resistant” does not mean hurricane “proof.”