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Hurricanes are Coming: Understand the Importance of Impact-Resistant Glass

English: Geraldo Rivera at a Hudson Union Soci...
English: Geraldo Rivera at a Hudson
Union Society event in September 2010.
 (Photo credit: Wikipedia)
By Gates Dearen

It was Geraldo Rivera, the well-known attorney, journalist, author, reporter and talk show host who once offered some great advice, especially for Florida homeowners, “Mother Nature may be forgiving this year, or next year, but eventually she’s going to come around and whack you. You’ve got to be prepared.”

The 2014 hurricane season begins in just three months and one of the best steps homeowners can do to be prepared for Florida’s thunderstorms, tornadoes and our notorious hurricanes, is to install high-quality, impact-resistant glass for their home windows.

There are several main differences between standard glass (single glazed pane), and an impact-resistant window. In fact, Florida’s standard/threshold is double that of other areas, which must be met in order for a window to qualify as being impact-resistant.

Impact-resistant windows and doors main design characteristics are their shatter-resistant glass, which is securely fastened to a heavy-duty aluminum frame. The impact-resistant glazing consists of two layers of annealed or tempered glass bonded to an intermediate shatterproof membrane layer. This membrane is typically made of Polyvinyl Butyral (PVB), a plastic film that varies in thickness from .015 to .090 inches, depending on the design pressures needed. Should the outer glass break, the broken pieces adhere to the PVB film. In contrast, standard-glass windows are made of standard float glass that, when broken, fractures into large, sharp shards, many of which fall out of the frame. Some dangle dangerously on the side, like sharks teeth, awaiting unsuspecting prey.

Courtesy of
For windows or door glass to be considered impact-resistant certified, they must meet the American Society for Testing and Materials’ (ASTM) qualifying standards. One of the most rigorous requirements comes from our own Florida Building Code. It takes into account the increase in frequency and strength of hurricanes in recent years. These standards incorporate many of the lessons learned from previous hurricane-driven disasters. The Florida Building Code, for example, requires that every exterior opening in a structure be protected against wind-borne debris. This protection can be accomplished by either installing impact-resistant windows or storm shutters, which I’ll discuss in another blog.

To be certified as impact-resistant, windows must pass several tests. Keep in mind, unlike bulletproof windows, the glass is expected to break. However, to be classified as impact-resistant, the pane shouldn’t shatter nor should it get pushed out of its frame. Generally, all impact-resistant glass must pass the following tests:

·      Launch Missile Impact Test. No, it’s not an explosive projectile screeching into your home. But almost. Here, a six-foot, nine-pound 2x4 wood stud is fired from a cannon at 80 feet per second (fps), at nearly 35 miles per hour, towards the center of the window. (FYI, most other states’ tests are at 50 fps.) If the window doesn't shatter, another board is shot at one of the window’s corners. Both the center and the corner of the window must be able to hold together to pass this test. There is also a small missile test, which subjects the window to a variety of impacts from 30 pieces of roof gravel at the same speed. Again, the window must pass the test in order be certified “impact-resistant.”

Following the Launch Missile Impact Test, the window is subsequently subjected to air pressures that simulate winds of up to 200 miles per hour. If the window remains intact within the frame, it can be certified as an impact-resistant window. NOTE: Making landfall near New Orleans, Hurricane Katrina was a Category 4 storm with gusts topping 140 miles an hour. When it slammed into Florida, Hurricane Andrew was a Category 5 storm, punching winds of 165 M.P.H.!
Hurricane Katrina making its second landfall i...
Hurricane Katrina making its second landfall in Louisiana,
as seen by NWS New Orleans radar. (Photo credit: Wikipedia
To learn whether a product is considered impact-resistant, ask your window dealer for a copy of its Notice of Acceptance (NOA) issued by your county of residence. The NOA certifies whether or not the product has passed the impact-resistant test.

As I said earlier, the advantages of installing impact-resistant windows are several-fold. In addition to keeping you and your loved ones safe, your home protected and, as well, your post-storm repair bills lower, impact-resistant windows allow you to obtain insurance premium discounts. Keep in mind, to qualify for these discounts or credits, all of your house’s openings must be protected. Concerning residential property insurance, Florida statute 627.0629 stipulates all insurance companies providing homeowner's insurance to the state’s residents must offer some type of discount for dwellings that have effective windstorm protection. If you have questions, you should contact your home insurance agent to ensure you receive proper credit for any steps you’ve taken to strengthen your home.

Impact-Resistant Means More Positive Impacts

Just because they’re strong enough to stop a wood 2x4 at 200 m.p.h., doesn’t mean your windows have to look bulky or unattractive. Impact-resistant windows are available in wide variety of color tints, including bronze, green, gray and blue. The window frames also can come in a variety of vinyl colors.

And even if there aren’t any imminent storms brewing, it doesn’t mean your home is immune to negative impacts from the outdoors. Consider long-term ultraviolet (UV) damage, for example, which can fade furniture, carpets and furnishings. Impact-resistant windows can also provide your home with increased ultraviolet protection. The lower the percentage, the more UV rays are being blocked. So a 0% UV value equals 100% blockage. For the best protection, gray and bronze tinted impact-resistant windows are best.

Impact-resistant Windows from HomeRite
Impact-resistant windows have also been proven to help with your energy savings. Scientists use the Solar Heat Gain Coefficient (SHGC), which represents the amount of heat going into a house. Florida, with its nearly six months of 80+ degree temperatures, has a lot of heat. The lower the SHGC number, the less heat penetrates into the house. Hurricane impact-resistant windows or doors with clear glass feature SHGC’s of 0.72, while bronze and gray glass hold a 0.55 and 0.56 SHGC value, respectively. The less heat seeping into your house, the higher you can set your thermostat, thus saving you money on A/C bills.

Due to the PVB film inside all impact-resistant windows, studies have found they’re much harder to break in to; therefore they act as a deterrent to would-be burglaries. In fact, fire personnel have special tools made especially for gaining inside access through impact-resistant glass. While not impossible to penetrate, it does take a would-be burglar more time to try to breach the glass. Obviously, this is ideal for exposing your average burglar because it takes them longer to penetrate the window or door. That’s more time, and noise that your alarm monitors, glass-break sensors or concerned neighbors have to notify the police.

In this article, I talked about the qualities, design and requisite testing of impact-resistant glass. I also mentioned several distinct advantages impact-resistant glass has over regular glass. If you have a comment about this article, please feel free to post it below. Also, if you found this article useful, please pass it on.

Gates Dearen is the co-owner of HomeRite Windows and Doors in Jacksonville, Florida. Owners Gates Dearen and Richard Walden have been serving the building products industry in Florida for over 25 years. We know the products, the industry, the market and what adds great value to a home.  Our approach is a little different.  We strive to match the homeowner with the right windows for their home and budget. Home improvements can be a hassle.  We’re here to make life easier with first-rate, energy efficient products; affordable prices; strong warranties and expert, award-winning installers that provide excellent service while respecting your home as if it were their own. 

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1 comment:

  1. Best to get prepared now. I recall well living through Hurricane Dora ... I was just a kid but it was scary. Ensure your doors and windows have the mettle to withstand all the force a major storm can bear.