Part I: In a World Full of Guns, Can Glass Make Us Safer?

by Thom Zaremba, shareholder at Roetzel & Andress

Sitting down to write this, I suddenly realized how quickly 2025 was coming to an end. I let my mind wander, and where it stopped surprised even me: of all things, I thought of Charlie Kirk. Just three months ago, Kirk was assassinated mid-sentence on a college campus in Utah by a bullet fired from a high-powered rifle on a nearby rooftop.

For me, it brought back memories of the many other assassinations that have occurred during my lifetime. I was barely in my teens when the peace and quiet of life in rural America was shattered as Walter Cronkite interrupted television’s limited programming in November of 1963 to report that President John F. Kennedy had been shot while riding in a Dallas motorcade. Not long after that, in 1965, the civil rights leader Malcolm X was assassinated in New York City. Just three years later, Martin Luther King was felled by an assassin’s bullet in Memphis and two months after that, Robert F. Kennedy was assassinated following a successful presidential primary campaign in California.

Guns are a part of American life. However, they are not always used for hunting or self-defense. In the wrong hands, they can create terror. As another year ends, I wonder, can glass make us safer?

In earlier blogs, we have seen how fire-rated glass can defeat burning buildings and wildfires. We have seen how the right type of glass can keep hurricane-force wind, rain and flying debris out of our homes. We’ve even seen how the wrong type of glass can be used as a litmus test to determine whether a house or building needs to be brought up to current code to keep us safe.

Let’s look at how glass’ ability to stop bullets could help keep us safe even when guns fall into the wrong hands!

Underwriters Laboratory (UL) has developed UL 752, a standard that establishes minimum performance requirements for testing the ballistic resistance of glass. Because different kinds of bullets and bullets from other types of guns strike with varying levels of penetrating force, the 11th edition of UL 752 rates the ballistic resistance of glass at 10 different levels, while its 12th edition uses a different categorization system. By rating 10 different levels of ballistic resistance, those using glass tested to UL 752’s 11th edition can assess the risk of a shooting at specific locations and select the most appropriate glass to mitigate that risk.

Suppose you are a jeweler with a store in a mall. Your security professional might conclude that your greatest risk would be from a concealed handgun. You would probably want the glass tested to one of UL 752’s first three levels to protect you.

To pass one of UL 752’s first three levels, glass assemblies must be able to stop three bullets fired from handguns. Level 1 tests 9 mm handguns; level 2 tests .357 handguns; and level 3 tests glass using a .44 magnum—remember the handgun Clint Eastwood used in Dirty Harry?

Now, suppose instead that you are scheduled to speak from a dais facing a large number of attendees spread out over a large open area. The threat assessment from your security professional includes the possible use of automatic gunfire, including a rifle. The glass you need for protection will be a different level of ballistic resistance than necessary to protect the jeweler.

Levels 4 through 10 of UL 752 rate the ballistic resistance of glass fired from high-powered rifles or successive fire from automatic weapons. UL 752 levels 4 and 5 rate single bullets fired from .30 caliber and .308 caliber rifles, while levels 6 through 8 rate bullets fired five times from a 9-millimeter handgun (level 6) or from 5.56 (level 7) or 7.62 (level 8) assault rifles. Levels 9 and 10 test the ability of glass to stop a single bullet fired from .30-06 and .50 caliber rifles.

Our jeweler could be protected from most handguns by using glass assemblies rated to a level 1, 2 or 3 of UL 752, while our speaker would need to be protected by glass ballistically rated to a UL 752 level 4 or above.

If we know how to, we can use glass to protect ourselves from burning buildings, wildfires, hurricanes and even guns that fall into the wrong hands. Stay tuned for next month’s blog when we’ll look at the 12^th edition of UL 752 and compare its ballistic resistance ratings to the forced entry resistance ratings of ASTM F3561.