Safety & Security

Bulletproof Glass

• By Michael S. Dorn
• 05/01/17

An increasingly common question from students, parents and school employees involves the use of “bulletproof” glass. Inaccurate media and social media discussions of active shooter and terrorist incidents have increased the level of fear among students, staff and parents. While there have not yet been a series of attacks where aggressors have shot victims through windows in the United States, such attacks are possible. The perceptions and realities make it natural for people to question whether or not ballistic protection for windows is appropriate. This issue now comes up quite often when schools are being (or have been) built with copious amounts of glass. There are specific situations where bulletproof glass is both appropriate and practical, but there are details to be considered.

Does Bulletproof Glass Exist?

As with police body armor, the term “bullet resistant” is infinitely more accurate. While there are a variety of high-quality products that can help provide ballistic protection for windows, there are challenges of stopping a wide array of projectiles with different weights travelling at different speeds. For example, stopping a 300-grain monolithic bullet fired from a .375 Holland and Holland caliber dangerous game hunting rifle requires a far higher degree of protection than would be required to stop a 115-grain hollow point bullet fired from a nine-millimeter handgun. Fortunately, outside of ivory poachers, criminals rarely utilize dangerous game rifles like the .375 Holland and Holland. In fact, I can’t recall a case where a criminal has used a dangerous game rifle to commit a crime in the United States. However, the fact is that there are a lot of calibers between these two extremes that must be considered.

Most experts in the field focus their attention on handgun calibers and popular calibers for tactical rifles such as the .223 Remington and the 7.62 X 39 millimeter cartridges commonly used in the AR-15 and AK-47 style rifles. For higher risk settings, protection for high-powered cartridges like the 7.62 NATO caliber may be considered. If this all this sounds technical to you, that is because it is! The discussion could be far more technical if we went into detail on projectile styles, velocities of specific cartridges and other details.

There are a variety of products that are capable of stopping multiple rounds from any of these weapons as long as they are designed and rated for the purpose, properly installed and supported by framing that is strong enough to prevent the windows from simply flexing out of the frame due to impact. Unfortunately, the factors that need to be considered for these types of protection are at least, if not even more, complex than this extremely brief description of ballistics.

Common Challenges for Protecting Windows from Ballistic Threats

There are numerous challenges and considerations for protecting building occupants from ballistic threats and glass. As with security, ballistic, fire, graffiti and wind protection approaches for windows, there are a host of highly technical considerations when selecting windows, laminates or glazing products to provide ballistic protection. For example, while some laminates will stop bullets fired from specific types of firearms, glass on the inside surface of some of these products can shatter and shower nearby occupants with flying glass shards that can cause serious injury, and in some cases, death. If laminates are applied only the window surface and not applied on the entire glass surface, the window may break at the edges upon impact and fall on occupants. These are but a few of the many challenges that make it necessary to identify the manufacturers of quality products and to have competent distributors with the highly technical knowledge to recommend practical solutions and install them properly.

The Good News

Now that we have discussed a few potential pitfalls of ballistic glass, I must point out that there are fortunately some great companies that offer excellent products. There are also qualified installers who can guide you in navigating these rocky but important waters. We advise our clients to focus on the quality of manufacturers and installers when examining ways to protect windows from ballistic threats. Cost, type of size and function of the windows and other factors need to be carefully evaluated and balanced with other security needs to create a good fit for performance, budget and lifecycle of the protective approach.

This article originally appeared in the issue of .