Understanding Glass Security: Categories, Testing, and Protection Against Manual and Ballistic Attacks

Glass can be classified into two main categories based on its intended use, safety and security.
Safety glass is designed to protect against accidental damage, while security glass is meant to withstand intentional harm. Security glass can be further categorized based on the type of threat it faces:

• Manual attack
• Ballistic attack

For manual attacks, laminated glass is typically recommended. Although toughened glass is strong, it can be relatively easily broken by someone with knowledge of its weaknesses. Additionally, toughened glass, when shattered, collapses and leaves an exposed, unprotected area. Laminated glass, on the other hand, can be engineered to resist various levels of force by adjusting the glass thickness and the interlayer that holds the glass together, thereby enhancing its ability to resist penetration. Even if broken, laminated glass continues to offer protection and slows down potential intruders. Combining toughened and laminated glass can provide a balance of strength, but this combination may result in a glass structure that loses integrity rapidly if both layers are compromised, allowing the glass to fold and potentially be removed from the frame.
European standards provide a broader range of categories for glass security, similar to the British Standard BS5544, but do not directly correlate categories with specific attack types. When selecting glass for protection against manual attacks, it is challenging to predict the force, determination, energy, and types of tools an attacker might use. The standard hard body drop tests cover many scenarios, while the axe test is designed for extreme situations.
Manual Attack
Under the European standard EN 356:1999, which tests and classifies glass based on its resistance to manual attacks, there are two main tests:

1. 1. Hard Body Drop Test:

Uses a 4.11 kg steel sphere (100mm in diameter) dropped from different heights.
Classifications:

1. • • • P1A: Glass withstands 3 drops from 1.5 meters.
       • P2A: Glass withstands 3 drops from 3 meters.
       • P3A: Glass withstands 3 drops from 6 meters.
       • P4A: Glass withstands 3 drops from 9 meters.
       • P5A: Glass withstands 9 drops from 9 meters.
2. Axe Test:

Involves impacts with a hammer followed by an axe.
Classifications based on the number of strikes needed to create an opening:

• • • P6B: 30 to 50 strikes.
    • P7B: 51 to 70 strikes.
    • P8B: More than 70 strikes.

Ballistic Attack
For ballistic attacks, glass and glass/plastic combinations are commonly used in bullet-resistant screens. These structures must endure the impact of projectiles, often through multiple layers of glass and interlayers that absorb the projectile’s energy. The glass is tested under severe conditions, assuming that the attacker aims directly at the glass and delivers precise strikes. While the design focuses on stopping bullets, managing issues such as spalling (the fragmentation of glass particles) is also important. The new standard EN 1063:1999 addresses these issues, offering classifications for different levels of ballistic resistance:

• • • BR1: Protection against a 0.22 LR rifle.
    • BR2: Protection against a 9mm Luger handgun.
    • BR3: Protection against a 0.357 Magnum handgun.
    • BR4: Protection against a 0.44 Rem Magnum handgun.
    • BR5: Protection against a 5.56 x 45 rifle.
    • BR6: Protection against a 7.62 x 51 rifle.
    • BR7: Protection against a 7.62 x 51 rifle with a different twist length.
    • SG1: Protection against a shotgun with a 12/70 calibre.
    • SG2: Protection against a 12/70 calibre shotgun with 3 strikes.

In situations where individuals are positioned behind the glass, opting for the no splinters (ns) option is crucial to ensure safety from glass fragments.