When (And When Not) To Use Tempered Glass Windows

By January 23, 2023 Uncategorized

Tempered glass windows are one of the most popular types of glazing for commercial buildings because they’re safer than standard annealed glass windows. But are they more secure?

Contrary to popular belief, tempered glass really isn’t all that much stronger than annealed glass, and it shouldn’t be relied on to improve commercial security.

What Are Tempered Glass Windows?

Tempered glass, also commonly referred to as tempered safety glass, is glass that has undergone a special treatment process to change the way it breaks.

The tempering process essentially uses extreme temperatures to put the interior layers of the glass into tension, while putting the outer layers into compression.

Because of this, broken tempered glass crumbles apart into thousands of relatively harmless granular pieces, instead of shattering into sharp, jagged shards, like annealed glass does.

These dull cubes of broken tempered glass present little to no risk of injury, whereas sharp shards of annealed glass can fly dangerously towards people and potentially cause serious harm. This is why tempered glass is used wherever human safety is a concern.

Common applications for tempered glass include:

  • Motor vehicles
  • Architectural glass
  • Glass furniture
  • Shower/tub enclosures
  • Glass railings and staircases
  • Commercial glass doors and windows
  • Aquariums
  • Dishes and cookware
  • Appliances

Basically, anywhere that humans have regular contact with or are close to glass surfaces that could potentially break is somewhere that tempered safety glass can be used to mitigate the risk of injury.

Why You Should Never Use Tempered Glass Windows for Security Applications

Many other sites online will claim that, because tempered glass is four to five times stronger than regular glass, you can use tempered glass to improve your building’s security. This is completely FALSE.

It’s true that the tempering process does make tempered glass windows slightly stronger than annealed glass windows, but this difference is not significant enough to make them any more secure than regular commercial glass windows.

Tempered glass is designed specifically to be broken, but in a way that makes it much safer than traditional glass.

But…you wouldn’t want to rely on glass that’s designed to be broken to keep out the bad guys or protect your property against storm damage, would you?

The only benefit of using tempered safety glass for your commercial facility’s doors and windows is that, in the event they get broken while someone is on the other side, there is less risk of injury to employees and anyone else in your building.

An intruder armed with a hammer, a bat, a pry bar, a rock, or any other heavy hand tool or object can quickly smash a tempered glass door or window apart and walk right into your business.

In fact, the bad guys will probably be happy you have tempered glass, as they’re less likely to get injured on their way in.

A robber using a sledgehammer to break the glass of a retail store.

Should you ever use tempered glass windows in commercial buildings?

All this is not to say that tempered safety glass doesn’t have its place in commercial facilities.

Tempered glass is still an excellent choice for interior glass doors and windows, wall partitions, and other interior architectural glass that’s not there to secure your business against would-be intruders or mother nature.

You should NOT use tempered glass for any easily accessible exterior doors and windows, such as glass entryway doors and retail storefront windows. It’s also not a good solution for glass surfaces that are prone to smash-and-grab theft attempts, such as display cases.

Besides the fact that tempered glass does nothing to stop forced entry or protect your business against storm damage, it’s also much more expensive to replace than standard window glass when it does eventually break. So, don’t use it for vulnerable windows and doors.

Tempered Glass Window Alternatives

Two popular and cost-effective alternatives to tempered glass windows where security is a concern are:

  1. Safety and security window film
  2. Polycarbonate security glazing

These two solutions are very different and provide completely different levels of security, so it’s important to understand how they work before you choose one.

Safety and security window film

Safety and security window film is a pliable poly-based coating that is applied directly to existing annealed glass surfaces to improve safety and security.

Like tempered glass, this type of window film is primarily intended to reduce hazards from broken glass. The film holds broken shards of glass in place, rather than allowing them to fly dangerously inwards.

However, safety and security window film is a superior solution to tempered glass when it comes to security.

Unlike tempered glass, which crumbles easily after a high force impact and leaves an opening, security window film can hold broken glass in place to delay and deter forced entry or continue acting as a barrier against inclement weather.

Window film does not prevent your glass from breaking, but it does provide more security than tempered glass, and is a very affordable solution when you want a basic security upgrade.

It’s important to note that security window film can be applied to tempered glass but the strength is far less than when installed on annealed glass. The reason for the lower strength is that tempered glass breaks into tiny cubes destabilizing the window unit and making the broken glass (even though held together with the film) easy to dislodge from the frame. Even when an attachment system is used at the edges, tempered glass with film is easily thwarted.

Polycarbonate security glazing

If your primary goal is to prevent forced entry and protect your business against other common security threats, the best solution is polycarbonate security glazing.

Whereas security window film only holds broken glass in place, polycarbonate creates a virtually unbreakable shield over your existing glass, typically preventing it from breaking or getting damaged at all due to any type of impact.

These polycarbonate glazing shields can be retrofitted over most doors and windows using the existing framing systems, so there’s no need for expensive glass replacement.

Polycarbonate is the ultimate in fenestration security because it altogether denies would-be intruders access to your property. It’s especially ideal wherever burglary and smash-and-grab theft are a concern, such as in luxury retail storefronts and display cases.

Polycarbonate security glazing can also be used as an alternative to board ups and roll-down shutters to protect your business against flying storm debris, rioting and looting, and vandalism.

The Bottom Line

Tempered safety glass is an innovative product that certainly has many useful applications — but security isn’t one of them.

For most commercial security glazing applications, we highly recommend a polycarbonate glazing shield retrofit, as this is a permanent solution that provides 24/7 protection against a full range of threats.

If you’re on a tight budget, security window film is an alternative that provides a basic level of protection, but polycarbonate is superior in every way.

Want help improving your fenestration security? Contact us today for a free consultation.