by Thom Zaremba, shareholder at Roetzel & Andress
A love of guns is built into America’s DNA, dating back to the Revolutionary War. In those days, there were no standing armies like today. Instead, Americans depended on local militias for protection.
Membership in the militia was often mandatory in early America and carried a requirement that everyone own their own gun and ammunition. Against that background, it is not surprising that the Second Amendment to the United States Constitution was ratified in 1791 as a part of the Bill of Rights, enshrining the right of every American to own and bear arms.
Today, Americans exercise their Second Amendment rights in astonishing numbers. A gun is sold in America on average every eleven and a half minutes. That adds up to about 45,000 gun purchases every year. Americans also load those guns, buying about 8.7 BILLION bullets every year!
With so many loaded guns, it’s not surprising that we have so many shootings. Although annual totals are dropping, the number of people killed or wounded by guns is still staggeringly high. In 2025, excluding suicides, 40,000 Americans were shot by guns, more than 110 people on average every day.
Properly selected ballistic-resistant glass doors, windows and walls can provide building occupants with safe shelter from almost any type of gun or bullet. Those helping design the glass for buildings should know how bullet-resistant glass assemblies are rated to enable them to properly protect building occupants from the different types of threats posed by armed gunmen.
Why the 12th Edition of UL 752 Was Necessary
In my last two blogs (Part I and Part II), we looked at the 11th and 12th editions of UL 752, which is perhaps the most widely used standard for evaluating ballistic-resistant glass assemblies. Now, we’re going to look closer at why a 12th edition of UL 752 became necessary.
The 11th edition may have created confusion by mixing linear and non-linear categories. While its categories one through three are linear, its categories four through 10 are not. The 12th edition eliminated this confusion by removing linear categories altogether. Its categories are based entirely on specific types of guns, ammunition and ballistic performance. This is not to say that a single type of glazing assembly might not be able to pass more than one level of testing under the 12th edition. However, any product passing more than one category of ballistic resistance would have to label them separately.
Another 12th edition change makes it clear that the standard only applies to architectural security systems such as doors, windows and other building enclosures. It does not apply to protective clothing or other devices that are worn, which have ratings issued by the National Institute of Justice.
Stronger Testing, Clearer Ratings, Better Protection
Other improvements to the 12th edition are its repeatability and its test for spalling.
The 12th edition made several changes calculated to ensure repeatability or a better “apples to apples” comparison of tested products. This was done to assure end users that every product labeled to the same category of performance—no matter the type of product, how it is constructed, the materials used to construct it or any other differences—provides the same ballistic protection as any other product labeled to that same level of performance. It did this by, among other things, requiring
- Better environmental conditioning for samples before they are tested;
- Requiring more samples to be tested;
- Requiring each sample to be shot more times;
- Improving the range of shot groupings for each rating; and
- Providing more detail as to where each bullet must strike the specimen to ensure that the weak points of architectural products are struck by bullets.
Finally, UL 752 doesn’t just test whether a glass assembly will stop bullets; it also tests whether anyone standing behind it when it’s struck by a bullet might be cut or injured from “spall.” Spalling happens when potentially dangerous fragments break off from the non-impacted side of an assembly that is struck by a bullet.
The cumulative effect of the 12th edition’s more stringent testing protocols makes the test more sensitive to spalling. For example, increasing the number of samples tested, increasing the number of shots per sample, and its stricter shot placement protocols all ensure a more consistent evaluation of spalling from across the entire test specimen.
I hope this blog will help improve the selection of ballistically resistant glazing assemblies where they’re needed to save lives. In my next blog, we’re going to begin looking at glass serving another lifesaving role—the “passive” fire protection needed to escape burning buildings! Please stay tuned!