Ballistic glass is used primarily to lessen the damage done by bullets to both property and human lives. It was first used on the battlefields during World War II in bunker and vehicle windows. Scientists found that they could stack various sheets of tempered glass and laminate them together with epoxy to create a bullet resistant glass that would protect soldiers from oncoming waves of bullets. Though it was advanced for its time, this early version of ballistic glass was nearly four inches thick, weighed upwards of 50 pounds, and could only be cut into small rectangles for use in windows. Engineers after the war began to expand the glass’ uses and explore further applications, like bank security. By combining technologies, they found ways to make ballistic glass suitable for other uses, most notably through the use of acrylic and plastic additives and fillers. Acrylic, though discovered in the 1800s, was especially brittle, but plastic additives and fillers formulated after the war created a more viable, stronger material. This new and improved version of ballistic glass is much thinner and can handle the same or more force. It also weighs a mere eight pounds per square foot, which is comparatively much lighter than older versions of the glass. It’s made of a single sheet of thermoplastic instead of multiple layers of tempered glass, which means that it can be milled, drilled, routed, and even flame polished. For this reason, it’s a flexible and appealing building material. It’s designed to absorb explosive force from projectiles in an effort to minimize the damage done to property and the amount of human injury in any environment. Today, bullet resistant glass is used in various settings including banks, fire stations, police stations, government agencies, and convenience stores among other commercial locations. We also have access to many more types of ballistic glass than we have in previous decades, such as monolithic acrylic glass, layered polycarbonate glass, and glass-clad polycarbonate.
Ballistic glass is made in various strengths according to different types of bullets. Stronger ballistic glass tends to be made with more layers of glass/plastic and can absorb much more force. Weaker ballistic glass is made with fewer layers, meaning it can’t absorb as much force. There are eight levels of ballistic glass, all ranging in strength. Level 1 ballistic glass can absorb the force from three 9mm bullets with a full metal copper jacket and a lead core. This level is used most often in gas stations, banks, pharmacies, and retail shops. Level 2 ballistic glass is able to handle the force of three .357 magnum jacketed lead soft point bullets. It’s most suited for use in corporate banks and other financial institutions. Level 3 ballistic glass can withstand impact from three .44 magnum lead core bullets and is typically found in police stations and other government agencies. Both level 4 and level 5 ballistic glass can only withstand one bullet, .30 caliber rifle lead core and 7.62mm rifle lead core with a full metal copper jacket respectively. They are suited for use in military and government settings. Levels 6-8 ballistic glass are also used most often in government and military settings. Level 6 glass can absorb the force from five 9mm full metal copper jacket lead core bullets, two more than level 1 ballistic glass. Level 7 ballistic glass is made to absorb the force from five 5.56mm rifle full metal copper jacket lead core bullets. Level 8 ballistic glass can withstand the impact of five 7.62mm rifle lead core full metal copper jacket bullets, four more than level 5 glass. Because there’s such a variety of ballistic glass available, it’s important that you know how to properly pick the right one. One of the biggest mistakes we see customers make is falling for over-protection. When you choose a more protective ballistic glass than you need you run the risk of overspending and your glass may be too thick. As you go up in protection, your glass will be made of more layers and subsequently be thicker and heavier. If you choose a variety of glass that’s too thick or heavy, your window frames may not be strong enough to support it. At Valley Glass, our technicians are prepared to assist you in picking the right glass for your business. We’ll measure your windows and take into account the material of the frames so that they will be able to support the weight and thickness of the glass you choose. If your business is in need of new ballistic glass, be sure sto give your nearest Valley Glass a call.