How to Identify Hurricane Impact Glass Windows

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September 2012

How to Identify Hurricane Impact Glass Windows?

High-impact glass, also known as laminated glass, consists of two glass sheets with a layer of PVB or resin in between. This structure allows the glass to withstand pressure, making breakage less likely. Unlike regular glass, which shatters into long shards, broken laminated glass stays in its frame. Commonly used in vehicles, high-impact glass can also be used in homes for safety, security, sound reduction and UV control.

Some tips to identify Impact Glass Windows.

  1. Look for a permanent mark in one of the four corners of the glass. This mark may include the supplier’s name, place of fabrication, date of manufacture, thickness and any certifications or safety standards the glass meets.
  2. Check the glass for a temporary label. While sheets of impact-resistant glass typically carry a mark on all four corners, the glass may have been cut in a way that excludes the mark. The manufacturer may affix a removable label that states the type of glass along with the information above.
  3. Examine a reflection in the glass. If you don’t find any markings or labels on the glass, hold your hand or an object up to the glass and carefully study the reflection. Because laminated glass consists of two sheets of glass, you should see two different reflections.

Why Should I Install Impact Resistant Windows On My Home in Miami?

Because impact resistant windows have advanced to the point where they are thoroughly tested to withstand Category 5, wind conditions and the debris that goes with it. What that means is that your home has a much better chance of remaining intact with minimal damage.

If one of your windows falls victim to a chunk of wood flying through it, the air pressure in your home will expand rapidly (much like a balloon) and something will give way. It could be your roof, another window, a door, or even a wall. Once that happens, your home is extremely vulnerable and will quickly deteriorate with each passing minute. Hopefully, you and your loved ones will be out of harm’s way (inland) and not be around to witness the destruction because it won’t be a pretty sight.

Are There Any Building Code Standards For Impact-Resistant Windows?

Impact resistant windows must meet certain guidelines in order to be marketed and sold as such. The American Society for Testing & Materials (ASTM) has strict guidelines (E1886 and E1996) for impact resistant windows before it can be certified as impact resistant. In south Florida, for instance, the building code states that all homes constructed after July 2001 must have hurricane shutters or impact resistant glass and window frames for exterior openings in a house to protect against wind-borne debris.

Codes will vary by community, but generally, impact resistant windows must meet these basic guidelines:

The first test is called a launch missile impact test. A 9-pound 2×4 wood stud is launched at 50 feet per second (fps), or almost 35 miles per hour, at the center of the window. If the window doesn’t shatter, another board is then shot at one of the corners of the window. Both the center and the corner of the window must be able to hold together to pass this test. Hurricane-prone Florida has slightly tougher testing standards, requiring windows to withstand boards launched at 80 fps.

After the launch missile impact test, the window is then subjected to 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.

Here is a 7 second video illustrating the testing procedure for a large missile impact test procedure required by ASTM 1886-1996. The window will be cycled thousands of times inward and outward at 1.5 times the design pressure to simulate actual category 5 hurricane conditions before being certified for sale as a hurricane impact window.