• Residential & Commercial Solutions for Security, Efficiency & Visibility.

  • Interesting Facts About Bulletproof Glass from James Access Controls

    The phrase “bulletproof glass” is a bit of a misnomer. No material is strong enough to be completely bulletproof. However, bulletproof glass or rather, bullet-resistant glass, is very effective at dissipating a bullet’s energy so it does not cause as much harm as it ordinarily would. In today’s Charlotte home security blog, we’ll take a look at bulletproof glass and how it works.

    Why Ordinary Glass Shatters

    When a bullet strikes a normal pane of glass, the glass cannot bend and absorb the energy gradually, so it shatters, allowing the bullet to continue with hardly any loss of momentum. Bulletproof glass, on the other hand, works to absorb and dissipate the energy so the bullet is slowed.

    One good way to understand bulletproof glass is by thinking of catching a very fast baseball. If your hand didn’t move at all, the force of the ball hitting it would hurt very much, and possibly even break your wrist. But if your hand and wrist bend backwards flexibly, the ball’s momentum changes gradually rather than suddenly, and the force of the impact is reduced. Mathematically speaking, if you took four times as long to stop the ball (for instance, two seconds instead of half a second), your hand would only feel a quarter as much force.

    How Bulletproof Glass Works

    Many people assume that bulletproof glass is simply regular glass that is many inches thick. However, bulletproof glass is actually composed of many layers of glass and plastic. Sometimes, the final inner layer is composed of a tough polycarbonate or plastic film, which prevents “spalling,” when where dangerous shards of glass or plastic splinter off following the impact of a bullet. The overall sandwich of layers is called a laminate. It can be up to ten times thicker than a single pane of ordinary glass, and is usually very heavy. 

    When a bullet strikes bulletproof glass, its energy spreads out sideways through the layers. Because the energy is divided between so many layers of glass and plastic, and spread over a large area, it is quickly absorbed, slowing the bullet down so that it no longer has enough energy to pierce through, or do much damage if it does so. Although the glass panes do break when shot, the plastic layers stop them from flying apart. Think of bulletproof glass as “energy-absorbing” glass, and you’ll have a good idea how it works.

    How Thick is Bulletproof Glass?

    The thickness of bulletproof glass varies greatly according to where it’s placed and how much protection the user needs (and how much they are willing to pay.) The thicker the glass, the more layers it has, and the more energy it can absorb. Basic bulletproof glass ranges from about 3cm (1.185 in) to 4cm (1.59 in) thick, but it can be made much more thick than that.

    However, problems arise when the glass is too thick. Very thick bulletproof glass is extremely heavy, making it difficult to use in, say, a car. Thicker bulletproof glass is also more opaque, because light also struggles to penetrate all those extra layers. Rapper Busta Rhymes ran into problems in in 2007 when police stopped his SUV, equipped with 5cm/2in-thick bulletproof glass, for “having excessively tinted windows” of only 70 percent light transmission.

    Get Bulletproof Glass, Surveillance Cameras, and More in Charlotte NC

    From Charlotte access controls, to security cameras, to gates and turnstiles, James Access Controls has everything you need to keep your Charlotte commercial or residential property safe from intruders. Feel free to browse our vast selection of security and access control products, and give us a call today to schedule a free installation estimate!