What Exactly Is Automotive Safety Glass?
We all know that glass is fragile and can break easily. Many of us have had first hand experiences with the dangers of broken glass. So then, why on earth would anyone sit behind the wheel of a car with a giant breakable windshield in front of them?
The answer is that your car windows are made of automotive safety glass. Automotive safety glass generally comes in two forms - laminated or tempered glass.
Let’s start by talking about laminated glass. As the name suggests, these windows are produced through a lamination process. This means that two pieces of automotive grade windows are glued together with a piece of lamination in the middle. This lamination layer is made of polyvinyl butyral. Polyvinyl butyral is just a fancy word for glue layer.
This glue layer is a requirement in automotive safety standards. All windshields installed on passenger vehicles for general road use have to be shatter resistant. The glue layer makes the glass shatter resistant by keeping all the broken pieces together in the case of a chip or crack. While the glue layer keeps a broken windshield from flying at your face, we still recommend a replacement as soon as possible. Broken windshields can be a hazard to your line of vision and to your vehicle's overall structural integrity.
In very rare and extreme circumstances, small shards of glass can break off from the windshield and not be held on by the glue layer. These types of extreme cases are usually the result of something large and heavy hitting the windshield with a lot of force. This is not an uncommon sight for us around Halloween. Every October we get one or two calls about a windshield being smashed by a giant pumpkin. The size and force of the impact usually causes small shards to break off and end up in the vehicle cabin. Luckily, there’s rarely ever a driver in the vehicle when this happens.
The second type of window is tempered glass. Tempering is the process of heat treating. When these types of windows get heat treated they become extremely hard, but also brittle. Tempered windows make up the overwhelming majority of windows on cars, with the exception of the windshield. This means your door windows, quarter glass and back glass are all tempered pieces. If you have aftermarket tint on your windows, they’ll still shatter, but have a higher likelihood of staying glued together. The tinting film acts like a glue layer in these cases, very similar to laminated glass.
Before I continue, I want to stress that you should not test what I’m about to explain. All types of glass can be dangerous, especially if you try to break it. That being said, tempered glass is tough to break through blunt force but once it does break, it almost always shatters into tiny pieces. These pieces are mostly harmless, although the smallest pieces can still stick you. As with all types of glass, you should treat broken tempered glass with care and clean it up as soon as possible.
All the windows in your car have to meet automotive safety standards. Whether they’re tempered or laminated, they’re meant to keep you and others safe while you’re out on the road. We hope your next drive comes with a Clear View.