 | Bob Crager of Lewis Street Glass is a 26 year veteran in the glass business. Lewis Street Glass is a leading Wichita Glass company, serving the entire Wichita/Sedgwick County area since 1919. They do anything and everything having to do with glass, both residential and commercial. They also do Auto glass. They are located at 743 South Market, facing Kellogg on the South, and you can reach them by phone at (316) 263-8259. You can email Bob Crager at bcrager@lewisstreetglass.com |
Glass
2005-11-01 16:19:00
Bullet proof glass
ANSWER: Did you know that on appearance, bullet-resistant glass looks identical to any ordinary pane of glass, but that's where the similarities come to an end. An ordinary piece of glass shatters when it is struck by a single bullet. Bullet resistant glass is designed to withstand one or several rounds of bullets, depending upon the thickness of the glass and the type and size of weapon being fired at it. So, what gives bullet resistant glass the ability to stop bullets? From the internet, I learned that different manufacturers make different variations of bullet resistant glass, but it is basically made by layering a polycarbonate material between pieces of ordinary glass in a process called lamination. This process creates a glass like material that is thicker than normal glass. Polycarbonate is a tough transparent plastic, and is often known by the brand names Lexan, Tuffak or Cyrolon. Bullet-resistant glass is between 7 millimeters and 75 millimeters in thickness. A bullet fired at a sheet of bullet resistant glass will pierce the outside layer of the glass, but the layered polycarbonate glass material is able to absorb the bullet's energy and stop it before it exits the final layer. The ability of bullet resistant glass to stop a bullet is determined by the thickness of the glass. A rifle bullet will collide with the glass with a lot more force than a bullet from a handgun, so a thicker piece of bullet resistant glass would be needed to stop a rifle bullet as opposed to a handgun bullet. There is also another type of bullet resistant glass available, which has one side that's able to stop bullets while the other side allows bullets to pass through it unaffected. This gives a person being shot at the ability to shoot back. This type of bullet resistant glass is made by laminating a brittle sheet of material with a flexible material. Imagine a car equipped with this one-way bullet resistant glass. If a person outside the car shoots a bullet into the window, the bullet would strike the brittle side first. This brittle material would shatter around the point of impact and absorb some of the energy over a large area. The flexible material then absorbs the remaining energy of the bullet, stopping the bullet. A bullet fired from inside the same car would easily pass through the glass because the bullet's force is concentrated on a small area, which causes the material to flex. This causes the brittle material to break outwards, allowing the bullet to pierce the flexible material and strike its target. But remember, it won't make much sense for you to have your car equipped with this kind of glass if it's a convertible and you ride around with the top down. More interesting stuff next month…
