This glass is manufactured by layering together sheets of laminated glass, acrylic, or both. The more layers you have, the more protection you have. These layers are bound together through a chemical process, thereby strengthening it enough to absorb the impact of a bullet or blast. The stopping power is directly proportional to the thickness. Framing systems for this glass can also be bullet resistant to offer added protection.
Three common types of ballistic security glass are bulletproof acrylic, laminated polycarbonate, and glass clad polycarbonate. These types of glass are rated on a 1-8 scale, with 8 providing the most protection. Commonly, small businesses choose level 1 security glass as a crime deterrent, as it provides enough protection to withstand shots from a small caliber handgun. Level 2, often selected by banks, can withstand higher caliber shots. Level 3 is recommended for buildings like police stations and government facilities, as they have a higher level of threat. Levels 4 – 8 tend to be more for military applications or for embassies overseas. Glass of the highest security like this is custom made and often quite costly.
Additionally, bullet proof glass can be fitted to vehicles, like police cruisers or armored vans.
Things to consider when evaluating options are weight, transparency/optical clarity, and thickness. Typically, the higher the rating level, the heavier the glass. The lower the rating level, the more optical clarity. Thickness is important when retrofitting older buildings, as thicker make-ups often don’t fit the glazing pocket. Lighter materials are more feasible for security doors or portable buildings, and for automotive applications.