The characteristics of bulletproof glass are such that they provide the ability to resist penetration when hit by projectiles. Optically transparent, bulletproof glass, also known as ballistic glass or transparent armor, can be made by combining two or more types of glass, one hard and one soft, or by inserting a safety laminate or plastic film onto the glass surface. In the first case, the bulletproof glass is made elastic by the presence of the soft layer, which causes it to flex instead of shattering; in the second case, the presence of the safety film provides protection similar to that guaranteed by multi-layered bulletproof glass.
How Is Bulletproof Glass Made?
But let’s look together at how bulletproof glass is made. The most commonly used production method today involves the use of two or more glass panes of varying thickness (6 – 10 mm), coupled together by a layer of elastomers (polyurethane or polyvinyl butyral, or PVB). These substances are ideal for making bulletproof glass due to their elasticity, tensile strength, and perfectly transparent aesthetic appearance. Should the glass pane be hit by a bullet, the elastomers keep the pane cohesive, preventing it from failing due to the impact.
The production process for bulletproof glass involves several steps: the glass panes are first cleaned and dried by specific machinery, followed by assembly through the lamination of glass panes and elastomer sheets; the panels thus assembled and layered are then pressed by special rollers and heated. In this way, every trace of air between the layers is eliminated and the elastomer is firmly bonded to the glass surfaces.
The degree of resistance of laminated bulletproof glass varies primarily based on the number and thickness of the panes and the layers of plastic interlayer used (PVB). Furthermore, it is important to take into account that the protection provided by a bullet-resistant glazing depends not only on the glass but also on the type of frame chosen, correct design, and an installation carried out to the highest standards. That is why, when it comes to security (and especially protection from bullets), it is essential to turn exclusively to industry professionals capable of ensuring impeccable service at all levels. Vetreria Re, active since 1989 in industrial glass processing as well as artistic glazings, is available for the creation of bulletproof glass for shop and bank windows, public buildings, vehicles, and much more.
The requirements for bullet-resistant glazings vary based on the number and thickness of the layers, as well as the specific production method of the bulletproof glass. Furthermore, the resistance of glass to bullets is verified through specific tests and trials that allow for the exact identification of the protection level offered by the bulletproof glazing. When hit by a bullet, the laminated glass ensures protection by remaining cohesive and preventing the bullet’s penetration. To better understand how bulletproof glass works, you can watch this video (the content of which is not suitable for minors and is absolutely not intended to inspire emulation. In other words, do not try this at home!), published in Italy by the newspaper website Repubblica, which shows a bulletproof tester putting the resistance of this excellent product to the test, putting himself on the line: https://www.youtube.com/watch?v=skbMnwQeOv4, ensuring a final high-quality finish.
Classification of Bulletproof Glass
As with accident-prevention glass and all structural glass applications in construction, bulletproof glass is also classified and regulated in its use by specific legal standards. In particular, the UNI EN 1063 standard, which classifies laminated glass as bulletproof, specifies the performance requirements and test methods (ballistic tests) that allow for the classification of bullet resistance of glazings based on the composition and final application of the panes (one or more layers of glass and glass/plastic composite sheets). The regulation establishes two different testing methodologies for the classification of bulletproof glass into various classes, providing resistance to bullets from handguns and rifles (classes BR1 to BR7) and shotgun slugs (classes SG1 to SG2). The application of the bulletproof standard extends to attacks with handguns, rifles, and shotguns, and to glazings for internal and external construction use.
According to the UNI EN 1063 standard, the term “bullet-resistant glazing” applies both to products made of 100% glass and to laminated products made of glass and plastic materials. For the classification of bulletproof glazings, it is necessary to perform at least one of the following types of ballistic tests:
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Resistance to bullets from handguns and rifles for bulletproof glass belonging to classes BR1 to BR7;
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Resistance to shotgun slugs for bulletproof glass belonging to classes SG1 to SG2.
Ballistic Test for Bulletproof Glass Let’s see together what the test indicating the bullet resistance of glass consists of and how it is performed. The ballistic test involves firing 3 shots at the center of 500×500 mm glass samples. The test results vary based on the type of weapon, bullet caliber, mass, distance from impact, and impact velocity. An essential requirement for the glass to pass the firearm resistance test is that none of the three bullets manage to penetrate the samples. Depending on the behavior of each individual sample, the bulletproof glass is classified into different resistance classes:
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Bulletproof Glazing Classified as Non-Splintering: If the bullets do not cause perforation of the bulletproof glazing (all or part of it), and if the witness sheet placed on the opposite face of the glass shows no trace of perforation from glass splinters, the glazing is classified in the appropriate bullet resistance class with the additional mark “NS” (no splinters).
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Bulletproof Glazing Classified as Splintering: If no penetrations occur in the bulletproof glass or part of it, but perforations due to glass splinters detached from the rear face of the glazing are observable on the witness sheet, the classification of the bullet-resistant glass will be further specified by the “S” (splinters) mark.
Regarding the areas of application for bulletproof glass, they are indicated for the creation of windows for jewelry stores, high-fashion boutiques, and precious object shops, bank counters, post offices, tax collection offices, credit institutions, insurance companies, gold buyers, and any office, commercial establishment, or public building where there is a consistent flow of money or valuables, as well as in museums, art galleries, and exhibitions of works, artifacts, and valuable objects, gun or explosive shops and, depending on risks, hospitality facilities, government offices, and residential properties, always ensuring top-tier acoustic silence and comfort.