Diana San Diego says suggestions that wired glass could have saved lives at the sites of various school shootings across the country by stopping bullets in their tracks or preventing forced entry are “false and potentially dangerous.”

San Diego, the marketing director for San Francisco-based Safti First, an American manufacturer of fire-rated glass and framing systems, takes strong exception to claims by an alleged security expert that wired glass in school windows or doors might have prevented or at least mitigated the tragedies made on a local Fox station in West Michigan.

“There is specific testing done for this,” she says, “and wired glass does not meet it.”

San Diego says that wired glass was never meant to be a safety product and credited the glass industry as a whole for making a lot of progress in protecting the public from potential danger with code changes and added product development.

Both she and Thomas S. Zaremba, a consultant to the glass industry with more than 30 years of experience with wired glass, strongly disagreed with the recent assertion by Lt. Col. Dave Grossman that wired glass might have lessened the human toll in a number of deadly school shootings. Grossman, a retired Army officer and former West Point professor now writing books, alleges that shoring up schools windows and doors with wired glass would have saved lives by denying the shooters entry.

Not true at all, insist those in the glass industry.

“I don’t know what kind of expert he’s supposed to be,” Zaremba says, “but, if he thinks wired glass is going to keep somebody with a gun out of a building, he doesn’t know anything about glass.”

Both San Diego and Zaremba worry that misinformed statements such as Grossman’s about wired glass security capabilities would improperly influence public opinions and lead concerned parents, students and administrators into a false sense of security and potentially toward more catastrophic injuries from wired glass.

Now limited in use, wired glass generally is half as strong as regular glass, San Diego says, and has been responsible in the past for a number of devastating injuries to school children. As an annealed glass, wired glass easily breaks into dangerous shards upon impact with its wires sticking out to cause even more extensive damage.

Hardly a reasonable solution, San Diego says.

“School shootings are a hot topic, and they should be,” she says. “There are ways to stop them, just not with wired glass.”

Zaremba, who says he was “very surprised” to hear Grossman’s comments, noted that wired glass can be layered in film to make it human-impact resistant, but even that added has limitations.

“At the end of the day,” he says, “if you have a baseball bat, you’re going to knock the wired glass right out of the frame. Whatever glass it is. I just don’t see wired glass as being an answer to keeping intruders out of a building.

“I think [Grossman] was just plain wrong.”


  1. Wired glass was typically used as a fire rated product mainly because the wire was able to keep the glass in the opening and prevent fire from spreading by feeding it oxygen. It was never considered a “safety” glass product and is easily broken – just ask any glazier who installed it in hollow metel doors how easily it breaks. It would not stand up to a gun shot and could very easily be removed from the opening with repeated strikes from a bat or a similar hard object

  2. No question that polished wire glass was intended solely as a fire redartation method
    and at no time during my association with the wire glass mfg. Mississippi Glass aka CE Glass, did we publish any informationto to the glass trade or the specifiers AIA/CSI,
    to the contrary. Dennis McKinny, Product Mgr.

  3. Having been in the Glass trade for 30 years, I know that ordinary Polished Plate and cast wired Glass was only ever intended as Fire resistant Glass to hold tohether during a fire. Pilkington did bring out a Safety wired Glass in the UK for doors etc where it needed both fire and safety. This had much thicker wires but would still not stop determined entry nor stop bullets.

  4. […] glass industry experts quoted by USGlass News Network had a few things to say on this topic as […]

  5. Having been to numerous courses taught by Dr. Grossman, having read all his books, and being a certified ALICE instructor, as well as certified active shooter/killer emergency response instructor, I have never heard Col. Grossman say, nor write, nor imply that wired glass would have prevented the killers from entering the school. What he does promote, however, is that reinforcing the glass with a protective film may slow down the killers for a short time, before they can get in. As the article said, even with a 4 minute response time, too many kids died in this case. We will never know, nor should anyone feel guilty about the possibility, that delaying the killers for even 30 seconds might have saved a life or lives. More importantly, he stresses that knowing the protective film is there might (best case) possibly deter the murderers, and at worst slow them down. Seconds count when a killer gets inside. The longer we can keep him/her out, the less people die.

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