An essential element of securing buildings is protecting them against ballistic threats, which is why most high-risk properties place bullet proof windows and doors at the top of their checklists. It should be noted, however, that when most people talk about bullet proof glass, they’re actually describing bullet resistant glass. This is because the nature of high-security glazing doesn’t make it completely impervious to bullets, but rather strong enough to resist an attack and give people time to escape or find shelter. To understand why this is the case, it’s essential to know how “bullet proof” glass works and what gives it its unique qualities.
How Bullet Resistant Windows and Doors Are Made
First, the glazing for a Bullet Resistant window can encompass a variety of compositions. The most popular types are acrylic, polycarbonate and glass.
There are many types of bullet resistant products that are made by sandwiching layers of polycarbonate and glass with a thin membrane of urethane or polyvinyl butyral between them. In some cases, they may be manufactured with glass used as the outside layers, creating what is typically called glass-clad polycarbonate. These are layered together in a sterile environment, then fused together using high levels of heat and pressure. No matter what the composition of the layers, these windows can range in thickness from ¾” up to 1 ¼ inches or thicker for much higher levels of protection.
Understanding the Principles Behind the Glass
Knowing how it is manufactured, how does bullet proof glass work? Most people might believe that it works by being so durable that bullets simply bounce off it, but the truth is more complex than that. The unique properties of this glazing give it the ability to absorb the impact of the bullet before it has a chance to completely penetrate the pane.
When a bullet first strikes a window or door, its energy is absorbed and spread over the entire surface. This reduces the level of force it exerts, so that by the time it reaches the next layer, its speed is greatly reduced. This occurs with each subsequent layer until the bullet is stopped. When it comes to ballistic windows, the material deforms and absorbs the bullet’s energy until it comes to a stop.
However, it is important to note that neither material is entirely impervious to bullets. Over time, a constant barrage of shots will eventually cause the window materials to degrade far enough that they will no longer be able to hold together. The most popular standard for determining the ballistic protective rating of a product is UL 752 – which you can also read about in our other blogs and ballistic standards page. The primary objective of these products is to allow enough time for a building’s occupants to reach safety and for the current threat to be stopped. In that regard, these are some of the best security measures for banks, government offices, schools and other types of buildings require from protection from all types of threats.
Choose U.S. Bullet Proofing
U.S. Bullet Proofing is a leader when it comes to the engineering, design and manufacturing of these bullet resistant systems.. Browse through our selection today or reach out to speak with one of our experts if you want to know more about what we have to offer.