The Florida Building Code
Types of Window Glass
Annealed glass is ordinary glass that has not been heat-strengthened or tempered. When broken, annealed glass breaks into large shards with sharp edges.
Tempered glass is heat-treated glass. The glass is heated, followed by the surface being cooled rapidly. Tempered glass is up to five times stronger than traditional glass. When broken, it does not break into large shards like annealed glass, but instead, shatters into small pebble-sized bits without dangerous edges that can cut or damage.
Laminated glass is created by bonding together two or more panes of glass with a thin layer of film or vinyl in between. This inner layer adds strength, and also prevents the window from shattering if it breaks. Instead, all the pieces stay stuck to the inner layer. It can also add UV protection and energy efficiency.
Impact-resistant glass is created by bonding together two or more panes of glass with a clear film between the panes. The thickness of this film can range, as can the UV tint or color. This film helps to hold the glass in place, making it resistant to impact.
While impact windows protect your home from flying debris and wind, hurricane windows take it one step further. They are configured to withstand hurricane-force winds, pressure and corrosion, and constructed to meet stringent building codes and local requirements.
5 Ways to Identify Hurricane-Impact Windows
1. Hurricane Windows Usually Have a Permanent Mark on the Glass
Impact-resistant glass takes longer and requires more expensive resources to produce than traditional glass. Because of this, hurricane window manufacturers want to make sure you know exactly what you’re investing in. Standard windows often have a peel-able label affixed to them, while impact resistant glass often has a more permanent marking printed or etched near one of the corners of the window. The marking on hurricane windows should include:
- Supplier’s name
- Place of fabrication
- Date the hurricane window was manufactured
- Thickness of the glass
- Certifications or safety standards that the glass meets.
- This marking may be an etched, frosted mark in the corner of the window that may be hard to find
- To make this easier, remove any grime around the glass and inspect it under good lighting
2. Check the Glass for a Temporary Label
Although most sheets of glass for impact resistant windows will carry a mark in the corner, each window is custom cut. In an effort to use as much glass per sheet as possible, the impact rating label may have been cut away. In this case, the manufacturer typically attaches a removable label that states the kind of glass and the information listed above.
3. Verify Your Hurricane Windows Are Designed for Conditions in Your Area
After you pull the information from the label, we recommend verifying that the thickness and safety standards meet or exceed the hurricane rating requirements in your area.
4. Examine the Reflection in the Glass
If you still can’t find any markings or labels on the glass, there’s one last test to determine whether you have impact resistant windows.
5. Ask an Impact Resistant Windows Expert
In the end, even if you find a label on your glass, it’s best to double-check that older windows still meet current standards. A professional installer will know exactly what the different ratings can withstand and can make custom recommendations for your home’s required (and desired) safety levels.