When designing a security solution, the choice between bullet-resistant glass and anti-intrusion glass is never straightforward. Both belong to the broader category of safety and security glass. However, they respond to fundamentally different protection needs. First of all, understanding the technical and regulatory differences between them helps identify the right solution for every application, from civil construction to defence, aerospace and security architecture.

What is anti-intrusion glass

Anti-intrusion glass is designed to resist break-in attempts, accidental impact or vandalism. Its primary function is to slow down or prevent access. As a result, this gives enough resistance time to deter intrusion or to allow law enforcement to intervene.

From a construction standpoint, anti-intrusion glass is generally a multi-layer laminated glass, made of several glass panes bonded with high-strength polymer interlayers. Consequently, as the number of layers and the overall thickness increase, so does the level of resistance to impact, repeated blows and attempted forced entry with hand tools.

For this reason, this type of glass is used in commercial buildings, banks, showrooms and private residences. More broadly, it is used in any setting where glazed openings need protection from intrusion attempts without requiring ballistic-grade performance.

What is bullet-resistant glass

Bullet-resistant, or ballistic, glass is engineered to withstand the impact of projectiles fired from firearms. Its goal is to stop penetration and protect what lies beyond the glazed surface. Additionally, this is a technologically more complex product, built from multiple layers of glass and polycarbonate calibrated to absorb and dissipate the kinetic energy of the impact.

Overall, the thickness and composition of the glazing package vary according to the required level of protection. This, in turn, depends on the weapon type, the projectile calibre and the firing distance defined by the threat scenario. For example, Isoclima develops bullet-resistant solutions for high-criticality sectors, including armoured vehicles and other applications for the defence sector and sensitive infrastructure, where ballistic protection is a non-negotiable requirement.

Reference standards (EN 356 vs EN 1063)

The distinction between the two glass types is also reflected precisely at the European regulatory level.

Firstly, standard EN 356 governs glass resistance to manual attack and impact. Specifically, it classifies products into classes from P1A to P8B, based on the number of blows withstood and the type of tool used in testing, from drop weight to axe. Overall, this is the reference standard for anti-intrusion glass.

Standard EN 1063, on the other hand, regulates the ballistic resistance of glass. In particular, it defines protection classes from BR1 to BR7, as well as specific classes for rifle ammunition (SG1, SG2). Each class corresponds to a defined weapon type, calibre and projectile velocity used in testing, which ensures an objective classification system that is comparable internationally.

Overall, knowing these classifications is essential for specifying the correct product at the tender stage. Above all, this helps avoid any ambiguity between mechanical protection levels and ballistic protection levels, which are in no way interchangeable.

When to choose one over the other

The choice between anti-intrusion glass and bullet-resistant glass depends on an assessment of the specific risk the project is exposed to. For instance, anti-intrusion glass is the right solution when the goal is to prevent theft, break-ins or vandalism in civil and commercial settings.

By contrast, bullet-resistant glass becomes necessary when there is a concrete risk associated with firearms, including institutional buildings, high-sensitivity banks, armoured vehicles, critical infrastructure and defence applications. In these contexts, ballistic protection is not an optional extra but a structural project requirement.

In many cases, the final decision also involves other variables, such as the overall weight of the structure and local industry regulations. For this reason, involving a technical partner during the design phase helps optimise the solution in relation to the actual level of threat.

Comparison table

Feature	Anti-intrusion glass	Bullet-resistant glass
Objective	Resistance to break-in, impact, vandalism	Stopping projectile penetration
Reference standard	EN 356	EN 1063
Classes	P1A to P8B	BR1 to BR7, SG1-SG2
Typical thickness	Moderate	Significant, depending on threat level
Main applications	Civil and commercial construction, retail, banks	Defence, armoured vehicles, critical infrastructure