Like most people, you probably take the glass in your car for granted. You might even assume that one piece of auto glass is the same as the next, but that is not the case at all. These days, in fact, two types of glass are most commonly used in passenger vehicles: tempered glass and laminated glass. Automotive glass does more than protect you from debris. It strengthens the entire car, deflects harmful UV rays which is important in Houston, allows for the proper deployment of passenger airbags and stays intact when it is penetrated or otherwise damaged. Whether your Houston vehicle needs windshield replacement or you are curious about auto glass, understanding the basics is easy.
Tempered auto glass is used on sidelites, which include passenger- and driver-side windows, and backlites, or rear windshields. During the manufacturing process, the glass is heated and then rapidly cooled by a series of blowers. This causes the surface to cool much more quickly than the center, which expands to produce tensile stresses. Meanwhile, the surface contracts to produce compressive stresses. The end result is glass that’s five to 10 times stronger and that boasts superior compressive and tensile strength. Weak edges are ground down to make them stronger, and when tempered glass breaks, it shatters into small, dull pieces due to the release of pent-up energy. Without tempered glass, potholes and other bumps in the road would make windows shatter, and passengers and drivers would be at risk of being seriously injured at any time.
The windshield acts as the first line of defense while driving down the road, so special considerations need to be made for the glass that is used. Modern cars have windshields that are made out of laminated glass, which consists of two sheets of glass with a center piece made out of polyvinyl butral, or PVB. These three layers are sealed with pressure rollers and then heated, which produces strong mechanical and chemical bonds.
The middle layer of PVB makes it possible for glass to absorb energy during an impact, and it also makes it highly resistant to penetration. As an added bonus, it effectively blocks about 95 percent of UV rays. Even if this glass is punctured or otherwise breaks, it remains intact.
Laminated glass helps to strengthen the roof of a car, which reduces the risk of it buckling and falling onto passengers during a crash or rollover accident. It also provides the strength that is needed for the passenger airbag to deploy correctly. Otherwise, the high speed of the deployment of the airbag would shatter the windshield and potentially injure the passenger.
Auto Glass in the Future
If auto glass improves even more, will mobile windshield repair even be necessary? Odds are that this type of service will always be needed to some degree. However, some auto manufacturers have toyed with the idea of using laminated glass on all windows in a car. This would be good in that it would make the car that much stronger, but there is a pretty big drawback: Laminated glass is so difficult to break that trapped passengers may be unable to escape if necessary.
Another possible development in auto glass in the near future is the increased popularity of cielo roofs, which are basically roofs that are entirely made out of laminated glass. The windshield basically continues up over the driver’s head.
The next time you need Houston auto glass repair or replacement, keep the specialized design of your car’s sidelites, windshield and backlite in mind. As much as you might take this glass for granted, it is going to protect you every time you hit the road. Without it, driving would be significantly more dangerous.