I. According to the protection level (Chinese/International Standard)
The grades of bulletproof glass are usually classified according to the types of firearms it can resist and the shooting distance. The following are the approximate thickness ranges for common grades:
Low-level protection (such as pistols)
Protected objects: Type 64, Type 54 pistols, 9mm pistols, etc.
Typical thickness: 20mm - 35mm
Structure: It is usually composed of three layers of glass and two layers of PVB/EVA film.
Medium-level protection (such as rifles)
Protected objects: Type 56 rifles, AK47, M16 and other assault rifles.
Typical thickness: 35mm - 55mm
Structure: Multiple layers of tempered glass are combined with high molecular materials. Sometimes, a polycarbonate (PC) layer is added to absorb impact energy and prevent back sputtering.
High-level protection (such as sniper rifles, high-intensity attacks)
Protected objects: Type 85 sniper rifles, M40 sniper rifles, and even more powerful weapons.
Typical thickness: 55mm - 100mm or thicker
Structure: A very complex multi-layer composite structure, usually consisting of multiple layers of glass, polycarbonate sheets and special bulletproof films. Both the thickness and weight have increased significantly.
Second, by application scenarios
The Windows of cash transport vehicles/VIP vehicles are usually 20mm to 35mm, and they need to balance protection with the vehicle's load capacity and lifting system capacity.
Bank counters/foreign currency exchange Windows: Usually 30mm - 50mm in size, they need to be bulletproof and often combined with anti-smashing functions.
Important building curtain walls, outposts and embassies: According to the threat assessment, the thickness may be 40mm - 80mm or more, and the area will be larger and the structure will be more solid.
Military/special vehicles and facilities: The thickness may exceed 100mm and is made of a combination of various materials such as glass, ceramics, and composite armor.
Iii. Core Influencing Factors
Materials and structure: Modern bulletproof glass is usually of a composite sandwich structure. The core is not merely to increase the thickness of the glass, but rather through:
Outer layer (hit layer) : High-strength tempered/chemically reinforced glass, which causes the warhead to deform and shatter, consuming its kinetic energy.
Middle layer: Flexible and transparent polymer materials (such as PVB, SGP, EVA, especially polycarbonate PC), absorb residual energy, firmly adhere to fragments, prevent penetration and backside splashing.
This "combination of rigidity and flexibility" structure has a better bulletproof effect than single-material materials of the same thickness, such as pure glass or pure plastic.
Protection grade standard: When purchasing, it must be customized in accordance with clear standards (such as China's GA standard, the United States' UL standard, and the European Union's EN standard), and the thickness must meet the test requirements of the corresponding grade.
Important Notes
Bulletproof has its limits: Any bulletproof glass has an upper limit of protection and can only ensure safety when facing designated weapons and ammunition within an effective shooting distance.
Thickness is positively correlated with weight: Bulletproof glass is extremely heavy, with a weight several times that of ordinary glass per square meter, and it has strict requirements for installation frames and building structures.
Professional customization: Bulletproof glass must be professionally designed and produced based on specific threat assessment, installation location and passed certification standards.
In summary, the thickness of bulletproof glass ranges from 2 centimeters to over 10 centimeters. The most common applications in banks and vehicles are mostly between 2 and 4 centimeters. The specific thickness must be determined by professional manufacturers based on the clear protection level requirements and application scenarios.
