The rise in urban crime, bomb explosions and terrorism, has created a need for glazing materials that enable people to carry on normally. The safety of personal property and the protection of human life, have become a greater concern in modern society.
Security glazing refers to the almost limitless family of products constructed from laminated glass, which is designed to withstand the complex dynamic structural loads resulting from specific safety and security threats.

Threats to facilities which can be countered with specific security glazing constructions include:

  1. Burglary and Forced Entry
  2. Bullet Resistant Glazing
  3. Ballistic Attacks
  4. Bomb Blasts
Residential and commercial burglaries are common occurences. Burglaries frequently are not directly aimed at a specific facility but toward targets of easy opportunity and low perceived risk. The most critical step in a burglary is entry. The most common means of entry involves entering through an open window, or through forced entry, by breaking a window to get to the door and window handles. Standard annealed or tempered glass offers little resistance to entry, since both can easily be broken. Tempered glass “explodes” when broken, creating an opening for easy access. Laminated glass resists penetration from common handheld tools and can reduce an intrusion.

Standard two-ply laminated architectural glass provides a significant improvement over monolithic glass products in resistance to forced entry from a variety of handheld weapons such as, hammers, crowbars and bricks. Furthermore, laminated glass cannot be cut from one side only, making quiet glass cutters useless as a burglary tool.

Laminated glazing , using a 1.52 mm. (0.060 in.) to 2.28 mm. (0.090 in.) interlayer will thwart most simple “smash and grab” burglaries, where the criminal can generate the impact energy to break the glass but cannot risk the time required to enter through the PVB interlayer. Security glazing can generally be used anywhere ordinary glass is required providing an effective substitute for other construction materials.

In more stringent security applications, such as a door to a bank or other high security (or high risk) facilities, sustained attacks with sophisticated weapons by more than one individual are possible. In these applications, glazing is generally required to resist penetration for some period of time, allowing other security measures at the site sufficient time to sense and respond to the attack.

Specific glazing installations (laminated glass and frame), can be designed and fabricated to resist such significant threats as concerted and unhurried attacks during periods of civil unrest and “ram raiding,” or breach of storefronts through moving vehicle impacts.

Laminated security glazing can successfully resist both penetration of bullets and impact induced spall (fragmentation from the protected side of the glazing) as a result of ballistic attacks. The ability of laminated glass to resist the penetration of bullets has typically been measured by using the UL 752 test requirements.
Laminated security glazing, supplied in common architectural glass thicknesses and weights using PVB interlayer, can substantially reduce injury from direct blast shock wave effects (overpressures) and flying or falling glass in bomb attacks, and can even reduce the cost to repair a bombed facility or a facility located near a bomb attack. Thicker security glazing specimens can actually exceed the strength of many common interior and exterior structural materials in resisting damage from bomb attacks or accidental explosions.

In urban bombings throughout the world, glass damage accounts for the majority of repair costs and is the primary instrument of human injury. Blasts propogate blast energy in all directions, which causes property damage, injury, flame, and destruction of buildings. If all of the glass lites installed in a building remain entirely within their frames, no glass will be propelled into the building or fall to the ground and cause injury. Furthermore, the building envelope will remain intact, and interior damage will be eliminated.

Government buildings and airports can benefit from the use of laminated security glass as passive resistance to small explosions. In prisons, laminated security glass can replace traditional bars to create a more humane environment.



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