How to Use Security Glass to Protect Storefront & Windows

By Mark Meshulam, REWC

Rioters breach U.S. Capital-Security glass should have been used
Rioters break glass at Capital
Rioters break non-security window glass at US Capital and gain unauthorized entry

It’s a sad fact of our times that broken glass has become a symbol and symptom of civil unrest, retail theft and vandalism. Fueled by inflammatory rhetoric and lax law enforcement, there is plenty disturbing action in the streets. We sadly see too much footage where people attack property and gain forced entry into stores in order to steal and vandalize.

Vandals and looters break glass
The #1 thing that vandals and burglers attack, is window or storefront glass. This violent act of breaking glass provides a dramatic statement, an emotional catharsis and a financial incentive: grabbing the goods inside. Sometimes, what starts as a peaceful demonstration, which is the lifeblood of our democracy, gets subverted by nefarious, opportunistic players who smash glass, enter, grab, loot, and attack other people.

This state of affairs is likely to remain with us for the foreseeable future. We see nothing on the horizon that will put a stop to smashing and grabbing. More than ever, retail, governmental and institutional buildings must step up their game and protect their physical boundaries, especially their window glass against attack.

Rioters break non-security door glass at US Capital and enter
Rioters break door glass and swarm inside the US Capital

Glass is the weakest link
The weakest part of most building facades is the ground level storefront or window glass, followed by the doors. If these things can be made to resist bad actors, outcomes will be dramatically improved. Businesses can reopen soon after an attack with merchandise intact. Governments can continue to function and institutions can continue to serve. But if the storefront or window glass and doors are breached, any chance of a quick reopening soon goes out the window.

Rioters break storefront window glass and loot store in New York
Rioters break storefront window glass in New York store. They enter and loot the store

Protecting window and storefront glass
This is a misnomer and strategically misguided. The objective is not to protect the glass against breakage. Let’s face it, when you hit the glass, it will likely break. The objective is to prevent unauthorized entry, even if the glass breaks. This is because, during an attack, most storefront or window glass will probably break when attacked. What we need is glass that does not break THROUGH, leaving a gaping hole for the hoards to enter.

Best security glazing: polycarbonate and bullet-resistant glass
The most common glazing that is used to repel vandals and robbers from entering your building involves the use of multi-layer laminated glass in new construction and polycarbonate glazing in retrofit. This article will focus on defending glass that already exists, so retrofit/overglaze polycarbonate systems will be discussed.

Rioters break glass and confront police at CNN in Atlanta
Violent rioters shatter non-security window glass and taunt police at CNN Headquarters in Atlanta

Polycarbonate – the security glazing of choice for fighting back against attack
Polycarbonates are transparent like glass, but flexible and very difficult to tear. If polycarbonate security glazing is used in a properly designed frame, it can take an amazing beating without letting the bad guy (or gal) through. Instead, the evil-doers tire of pounding on the polycarbonate and move on to weaker buildings.

What is polycarbonate security glass?
First I will tell you what it is not. It is not “Plexiglas” or a similar acrylic-based glazing material. The acrylic family looks nearly identical to polycarbonate (it’s a clear sheet), but it is much more brittle and cracks more readily under impact. If you want to protect your glass against nefarious attack, do not use acrylic glazing.

Polycarbonate is made from fossil fuels. It is very strong and flexible. Its ability to withstand attack is due to its flexibility. Instead of acting like an unyielding brick wall, it absorbs shock and sends the energy out to the edges of the panel, and also bounces the attack weapon back at the perpetrator.

Polycarbonate security glass has undergone great improvement over the years so that yellowing is reduced or eliminated. Since polycarbonate has a relatively high coefficient of thermal expansion, only specially designed frames can be used, else the panel will bulge, sometimes called “pillowing”. It might bulge inward or outward, varying even on adjacent panels. So the movement must be accommodated in the frame design, allowing the panel to grow while maintaining flatness.

Chart comparing glass with acrylic with polycarbonate securrity glass
Chart comparing glass with acrylic and polycarbonate

Polycarbonate security glass overglaze system
To protect storefront or window glass from unauthorized entry of vandals, rioters and looters, polycarbonate sheets are often anchored either outside or inside the existing glass in a specially engineered and tested system that is attached to the existing window system.

Polycarbonate overglaze security glass system is used to protect window glass from attack
Polycarbonate overglaze security glass system covers existing storefront glass and repels rioters

Levels of Protection
The glass industry has a system for defining and testing levels of protection against attack. This can be found in ASTM F1233-08 (reapproved 2019), Standard Test Method for Security Glazing Materials and Systems.
This 13-page industry standard divides attack levels into two main categories, forced entry and ballistic attack. Either type of attack might occur by itself, or both might occur in concert. Failure occurs at “contraband” level when a 1/8″ diameter object can be passed through the system. “Body-passage” failure occurs when a rectangular 8″ x 8″ x 5″ object can be shoved through the system with up to 10lbs of force.

Predictably, each enhanced level of protection comes with a correspondingly enhanced price tag. Therefore, building owners and managers must make careful, educated buying decisions in order to get the most needed protection at a price they can afford. I know of no cookbook for making such decisions. What is needed is a property inspection and risk assessment by a skilled consultant. Contact me and I will help you with an appropriate referral.

Implements and weapons used when attacking window glass
Implements and weapons vandals might use when attacking storefront or window glass

How to test protective security glazing systems
The most commonly used test protocol used for protective security glazing systems is ASTM F3038, Standard Test Method for Timed Evaluation of Forced-Entry-Resistant Systems. The test describes its purpose: “to simulate a spontaneous mob using readily available hand tools as the primary threat for forced entry”. In other words, to simulate an attack.

In this test, a group of six perpetrators attack the panel with a succession of nasty objects that are made available for their choosing, with suggestions and cheering-on by a “test manager” who has the blueprints of the system. The tools include chisels, hammers, crowbars, an axe, bolt cutter, screwdriver, hack saw, various wrenches and to top it off, a 120-lb battering ram.

The attack is timed. For attacking fixed window glazing, the attack focuses on three areas, the corner, the center of glazing and the “glazing pocket”. The point at which one penetration of an elliptical cylinder measuring 400 mm (15.75″) x 225 mm (8.86″) x 300 mm (11.81) in height can be passed through the system determines the level of protection. The levels are 5 minutes, 15 minutes, 30 minutes and 60 minutes.

The security glazing tests are, as you might imagine, entertaining. Watching young stud-muffins doing their worst on the security glass is satisfying and fun, especially if they don’t succeed. But the test has a greater purpose: to demonstrate that the glazing system really works. Which, if done right, it does.

I serve as technical consultant for a manufacturer ( who has evolved a very reliable product for keeping rioters out of buildings using polycarbonate glazing. If you will tell me something about your building and its threat level, I can help you determine if polycarbonate glazing is a solution that fits your property, and I can introduce you to the people who can make it happen for you.

Cell phone stores are early adopters of polycarbonate overglazing security glass systems
Cell phone stores are early adopters of polycarbonate overglaze security glass systems

First adopters of polycarbonate overglaze security glass systems
In the marketplace, we are seeing the greatest adoption of polycarbonate overglaze security glass systems from cellular phone stores, shoe stores, high value retail, schools and religious institutions. I predict that the big drug stores will soon join the bandwagon. In my travels, especially in San Francisco, I see large drug stores that are completely boarded up on the outside, weeks or months after a riot occurred. This makes the buying experience in such stores weird and unsettling as no natural light reaches the space through the plywood. The rest of the retail world is sure to follow as they watch their better protected neighbors survive violent assaults.

As we adapt to a new reality where criminals break storefront or window glass and steal everything in sight, savvy properties will sport a transparent glass-like solution that will take a licking without failure, and send vandals off to find an easier victim.

Door glass is attacked but polycarbonate security glass still keeps rioters out
Door glass is attacked but polycarbonate security glass still keeps rioters out
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