Bulletproof Glass
The bulletproof glass is a special category of glazing, manufactured for high-security areas such as banks, museums, jewelry stores, etc. It is constructed with three or more glass layers (many joined panes – many layers – multi-layered) of different thicknesses, between which a special membrane is inserted to meet the required security level. Please see the security levels of frames.
We should note that due to the heavy weight of bulletproof glass, special mechanisms and special aluminum profiles are required for the construction of frames. See which ones by searching under aluminum frames.
Impact Energy
A significant factor in the production of these glazings is the impact energy (measured in Joules depending on the mass and velocity of the projectile), which depends on the type of firearm and the projectile.
International standards define the category of bulletproof glass, such as BS 5051, which specifies the performance level and testing methods for the six categories of bulletproof glazings in indoor environments to withstand a shot from a firearm (revolver, rifle, shotgun).
Bulletproof Glass Categories
| Category | Caliber | Weapon | Projectile Velocity | Number of Shots |
|---|---|---|---|---|
| BR1 | 0.22 Long Rifle | Long Rifle | 360 m/s | 3 |
| BR2 | 9mm Parabellum | Luger, Uzi | 400 m/s | 3 |
| BR3 | 0.357 Magnum | Magnum | 430 m/s | 3 |
| BR4 | 0.44 Magnum | Magnum | 440 m/s | 3 |
| BR5 | 5.56 × 45mm | M16 | 950 m/s | 3 |
| BR6 | 7.62 × 51mm soft core | FAL / Winchester | 820 m/s | 3 |
| BR7 | 7.62 × 51mm hard core | FAL | 830 m/s | 3 |
| SG1 | 12 / 70 | Riotgun | 420 m/s | 1 |
| SG2 | 12 / 70 | Riotgun | 420 m/s | 3 |
Category (BR / SG)
Indicates the level of protection. The higher the number (e.g., BR7), the greater the resistance.
BR = protection against rifles/pistols
SG = protection against shotgun
Caliber
The type and size of the cartridge.
Weapon
Indicative type of weapon used in the test.
Projectile velocity (m/s)
The speed at which the projectile impacts the material during testing. The higher the speed, the stronger the impact.
Number of shots
How many consecutive shots the material must withstand without penetration.
Level Interpretation
BR1 – BR4
Protection against pistols of various calibers (lower to medium power).BR5 – BR7
Protection against military-grade rifles.
BR7 is among the highest levels and includes hard-core (armor-piercing) projectiles.SG1 – SG2
Refer to 12/70 shotgun.
The difference is in the number of shots (1 or 3).
Practical Applications for Security Glazing
High-security residences: usually BR2–BR4
Banks, public buildings, military installations: BR5–BR7
