Bullet Resistant Glass is generally wrapped in an aluminum, wood, or steel frame acting as a door, window or wall panel. The glass can be produced with different materials such as layers of glass (lamination), acrylic, polycarbonate glass, glass clad polycarbonate or fiberglass. The weight and thickness of the glass will vary depending on the materials used. Bullet resistant glass has a rating protection (level) which has been tested and approved from Underwriters Laboratories Inc. (UL) or the National Institute of Justice (NIJ). Protection Ratings are numbered from 1, which is the lowest to 8, which is the highest. Generally, typical bullet resistant systems that you would see at a gas station, bank, pharmacy, or even some low profile public government buildings do not exceed the level 4 rating. Military facilities, facilities that store very sensitive information and military vehicles use levels 5 through 8 protection as they require the strongest materials and are capable of stopping many AK-47 rounds and even high caliber rifle rounds like a .50 caliber sniper bullet.
Underwriter Laboratories is the primary testing organization for bullet resistant materials. Each level has been tested and found effective at stopping weapons most commonly used during an armed robbery and even weapons used for force entry like sledgehammers.
This chart shows which levels of resistance
stops certain sizes of ammunition
UL PROTECTION LEVELS EXPLAINED
EXAMPLES OF LEVEL 3 PROTECTION
MATERIAL options FOR BULLET RESISTAnt systems
Least sought after material for a bullet resistant system.
Cannot be cut, drilled or routed during manufacturing
Constructed of layers of glass and resin, similar to a car windshield
Usually not used in modern bullet resistant systems due to its heavy weight and limited functions, but laminate is used in combination with polycarbonate materials.
Takes on average 6 to 8 weeks to produce, which is much longer than other materials.
Up to protection level 4
Most commonly seen material used for bullet resistant systems
Can be cut, drilled and routed in the factory during manufacturing.
Can easily integrate with mounting and framing hardware, making it very versatile.
Light passes through perfectly, making it the ideal choice for transaction windows.
Commonly seen in gas stations, retail, pharmacies, pawn shops and check cashiers.
Most effective against low power firearms like 9mm pistols and .357 revolvers.
Up to protection level 2
Systems that utilize polycarbonate are constructed with layers of laminate inside of the glass.
Polycarbonite is softer than acrylic thus making it unlikely to create glass projectiles upon bullet impact.
Capable of protecting against forced entry, unlike acrylic which could be compromised within minutes. Polycarbonate material can withstand an hour long sledgehammer attack
Has excellent optical clarity and weighs less than other bullet resistant materials.
Commonly used as exterior windows at police stations, governmental and utility facilities
Can withstand 3 shots from a .44 magnum.
Protection up to level 4
Glass Clad Polycarbonate:
Is comprised of layers. 3/8" glass, a thin layer of polyurethane between another layer of 3/8" glass, sandwiched between 1/8" layers of polycarbonate. This is the standard for a level 3 glass clad polycarbonate panel.
Total thickness for a level 3 glass panel is just over an inch thick.
These inch thick panels can be made thicker and thicker to achieve the highest-rated levels of bullet resistance.
Glass clad polycarbonate materials can withstand harsh outdoor enviroments, and is also known for its optical quality.
Is usually installed as an exterior window, unlike acrylic which is used as a bullet resistant barrier indoors.
Does not create any glass or bullet projectiles but rather "catches" the bullet in the glass.
Capable of protecting against explosions, gale force winds, and forced entry; thicker panels are capable of stopping .50 caliber sniper rounds and M16 bursts.
Protection up to level 8