In our shop there’s a thick panel of glass with three bullets lodged in it. It’s right in the front of the shop in our gallery. As you can imagine, it is quite the conversation piece.
Like most people, I take bulletproof glass at face value without much thought. I pretty much just go along with what I’ve seen in the movies. The bullets bounce off the glass and that’s it. It turns out, there’s a lot more to bulletproof glass than that.
All In the Name
Let’s start with the name. Bulletproof glass isn’t exactly glass (we’ll talk more about that later) and it’s not really bulletproof. Nothing is purely indestructible and bulletproof glass is no exception. It’s more like bullet resistant glass. Often times security companies refer to it as bullet resistant glass or ballistics glass. Neither of those has the same ring as bulletproof glass, though.
Bulletproof glass is designed to absorb the impact of bullets for a time, but it will eventually break. The goal is to give the person on the other side a chance to escape to safety. There are eight different ratings or levels of resistance. The higher the number, the greater the resistance. A level 1 rated panel can stop about three bullets from a small caliber handgun. A level 8 rated panel can stop a few rounds from an assault rifle.
How Is That Possible?
Looking at the display in our shop, it basically looks like a thick piece of plastic. I know there’s more than meets the eye, so I did a little research to find out how plastic can stop a bullet in its tracks.
Since I’m no scientist, I’ll explain it in layman’s terms. Regular glass shatters when it gets hit by something. Bulletproof glass essentially absorbs that hit and spreads it across multiple layers. This spreading of energy in effect stops the bullet in its tracks. Interestingly, it’s not like the movies where the bullets just bounce off.
There have been lots of advancements over the decades. New innovations in manufacturing bulletproof glass have given way to multiple types of bulletproof glass.
Let’s think about bulletproof glass in three types: laminated glass, polycarbonate, and acrylic. It’s way more complex than that, but for this brief introduction we’ll keep it simple.
We’ll start with laminated glass. It is just layers of glass and plastic sandwiched together and bonded. When a bullet hits the panel it does indeed break a few layers of glass, but the plastic absorbs the impact and slows the bullet down enough that it cannot continue moving through the panel. Because it’s layered glass, It is often the heaviest option you’ll find.
Another type of bulletproof glass doesn’t use glass at all. It is simply a very thick piece of acrylic. Acrylic is stronger than glass and offers about the same clarity and visibility. Panels made from acrylic are perfect for areas where visibility is very important, like customer service counters.
Polycarbonate is yet another option. It can be either laminated or glass-clad. Laminated polycarbonate is basically layers of polycarbonate. The thicker, the more bullet resistant. Polycarbonate is softer than glass and acrylic, so instead of shattering, it kind of sucks the bullet in.
There’s also glass-clad polycarbonate. This is layers of glass and polycarbonate bonded together. It can be layered to achieve any resistance rating. It offers less visibility than glass and acrylic, but it’s the cream of the crop in terms of bullet resistance.
Polycarbonate is also highly resistant to forced entry. So, you can hit it with a baseball bat or a sledgehammer and it’ll be fine (hence the term ballistics glass). Unfortunately, layers of polycarbonate don’t have the same clarity as glass and acrylic. If tinting is a concern, it may not be the best option.
More Than Cool
The advancements in the plastic industry never cease to amaze me. Even something that seems as straightforward as bulletproof glass has decades of innovation behind it. All those advancements and innovations come together to produce something that makes our lives better and safer.