Bulletproof

“Bulletproof” glass is very different to normal glass. More correctly called bullet-resistant glass (because no glass is totally bulletproof), it is made from layers of tough plastic called polycarbonate sandwiched in between pieces of toughened glass. This sandwich of layers is called a laminate. It can be up to ten times thicker than a single pane of ordinary glass and it is usually very heavy. When a bullet strikes bullet resistant glass, its energy spreads out sideways through the layers. Because the energy is divided between a number of different pieces of glass and polycarbonate interlayers, and spread over a large area, it is quickly absorbed. The bullet slows down so much that it no longer has enough energy to pierce through – or to do much damage if it does so. Although the glass panes do break, the polycarbonate layers stop them flying apart. Think of bullet resistant glass as “energy-absorbing” glass and you’ll have a good idea how it works. This is the same principle for the framework. The heavy duty steel sections are heavily reinforced with sandwiches of steel, therefore when a bullet strikes the steel, its energy is quickly absorbed.