Whenever hurricane season rolls around, many homeowners in hurricane-prone states start talking about impact windows. Should you buy them? Are they worth it? Are they hideous? Another question that sometimes gets asked is: Can impact windows withstand a Category 5 hurricane? While the answers to the previous questions are yes, yes, and no, respectively, the answer to that last question isn’t quite as straightforward.
Impact windows are, of course, designed to withstand hurricanes and other harsh weather, and they’re rigorously tested with storm simulations to ensure strength and quality in the face of these conditions. That said, it’s important to remember that impact-resistant windows are impact-resistant, not impact-proof. While they’re incredibly durable and engineered specifically to withstand the force of a heavy impact, they’re not totally indestructible. And it’s difficult to say with certainty whether any one specific impact-resistant window would survive a hypothetical Category 5 hurricane. Surely, some impact-resistant windows would survive the storm (i.e., they’re not all just going to simultaneously combust due to the wind and air pressure if a Category 5 storm hits) but if the wind from a powerful Category 5 storm were to hurl a piece of debris at an impact-resistant window, there is certainly a chance that the window could break. Of course, it will depend on what the debris is, how heavy it is, how directly it hits the window, etc.
What’s great about impact windows is that their safety design goes beyond just durability. They’re also equipped with a layer of rigid yet flexible plastic-like material in between the panes of glass, much like a car windshield. So, if a piece of debris does hit your window hard enough to break it, this interlayer will hold the shattered bits of glass in place so they won’t go flying into your home and cause injury.
How Impact Windows Are Rated
At this point, you may be wondering how a window earns its impact rating. What, exactly, distinguishes an impact-resistant window from its non-impact counterpart? As mentioned above, the glass in impact windows is specially treated to prevent it from shattering into sharp shards when struck by an object. What’s more, even if something hits the glass hard enough for it to break, it’s designed to crumble into pebble-like chunks that are much less likely to cause lacerations when airborne. But that’s only one of the distinguishing features of impact windows. They also boast reinforced frames, upgraded hardware, and extra-strong seals, all of which are laboratory tested to verify their effectiveness in preventing water and air infiltration.
For impact windows, the two ratings that set them apart from standard windows are their DP (design pressure) ratings, and their PG (performance grade) ratings.
The design pressure rating is a numerical value that indicates a window’s ability to withstand two things: wind pressure and water penetration. The higher the designation, the greater its resistance to these forces. A DP rating of 50, for instance, indicates the window has been subjected to and withstood wind speeds of 200 mph and eight inches of rain driven against it at 50 mph. Generally speaking, every 10 points in a DP rating can be associated with a window’s ability to withstand an equivalently ranked hurricane, with a 50 rating corresponding to a Category 5 hurricane, a 40 rating corresponding to a Category 4 storm, and so on.
While DP ratings only take into account wind and rain resistance, PG ratings factor in a third component: structural integrity. Since PG ratings are more comprehensive than DP ratings, they are considered a superior evaluation method. PG ratings use a similar scale to DP ratings, but they may not be identical due to variations in frame strength.
Want to Learn More?
If you’d like to learn more about impact windows and whether or not they’re a good choice for your home, click here to locate the nearest Sunrise Windows dealer. He or she will be happy to tell you all about our Coastal Performance windows and how they can help protect your home and family when hurricane season rolls around.