Ballistic Resistance: Standards, Ratings and Certified Bullet Resistant Products for UK Critical Infrastructure

What Is Ballistic Resistance?

Ballistic resistance is the independently verified ability of a building component, such as a door, window, glazing panel or curtain wall system, to withstand penetration by live ammunition fired from a specified weapon at a defined velocity and range. When a firearm is discharged at a building, the projectile carries enormous kinetic energy. Without certified ballistic protection, a standard door or window offers negligible resistance and will be penetrated, with lethal consequences for anyone in the line of fire beyond it.

A bullet resistant product is one that has been fired upon by an independent accredited test laboratory using the specified ammunition for its class, and shown to prevent perforation of the protected face. The test also records whether material splintered from the interior face during the test, producing either an S (spall present) or NS (no spall) suffix that is an important part of the full rating.

The correct industry term is bullet resistant, not bulletproof. No building product can be guaranteed against every possible firearm threat. A product rated to FB6 has been proven to resist a specific calibre at a specific velocity under defined test conditions. It has not been tested against every weapon ever made. Understanding what a rating certifies, and what it does not, is fundamental to specifying correctly.

Who Needs Bullet Resistant Doors, Windows and Glazing?

Ballistic protection is specified wherever the credible threat includes a firearms attack, whether from armed robbery, terrorism, hostile state actors or organised crime. The following sectors routinely specify bullet resistant building products:

• Government & Public Buildings
• Embassies & High Commissions
• Military Installations & MOD Facilities
• Police Stations & Custody Suites
• Critical National Infrastructure (CNI)
• Armouries & Secure Storage
• Banks & Financial Institutions
• Courts & Justice Buildings
• Data Centres & Secure Server Rooms
• Safe Rooms & Panic Rooms
• Communications & Operations Rooms
• High-Value Retail

Threat assessments for these buildings are typically conducted by qualified security consultants working within NPSA (National Protective Security Authority) guidance frameworks. The outcome of that assessment defines the required ballistic rating, which in turn determines the product specification. Premier Security's technical team works directly with architects, security consultants and main contractors to ensure the right rating is specified for every project.

Ballistic Resistance Standards Explained

Several standards govern ballistic resistance testing and classification for building products in the UK and internationally. Premier Security's products are tested to EN 1522 and EN 1523, the primary European standards for complete fenestration assemblies. EN 1063 is included here as contextual guidance, as it applies to glazing alone and is the glazing standard that pairs with EN 1522/1523. UL 752 and NIJ 0108.01 are US standards included for specifier reference, as they may appear in internationally referenced project documentation.

EN 1522 / EN 1523: The Primary European Ballistic Standard for Assemblies

EN 1522:1999 and EN 1523:1999 are the European standards governing ballistic resistance testing of complete fenestration assemblies including windows, doors, shutters, blinds, louvres and curtain walling. EN 1522 defines the requirements and classification. EN 1523 defines the test method. Together they represent the primary specification reference for bullet resistant building products throughout the UK and Europe.

Premier Security's bullet resistant doors and windows are independently tested to EN 1522 and EN 1523 by D J Goode of Suffolk, an accredited ballistic test laboratory. All test results are supported by formal independent test reports available to specifiers as part of the product submission package.

What EN 1522 Tests

Three shots are fired at the assembly in a triangular pattern at defined impact points, using the specified ammunition for the class being tested. Test ranges are 5m for handgun calibres (FB2 to FB4) and 10m for rifle and shotgun calibres (FB1, FB5, FB6, FB7, FSG). The required impact velocity at the specimen face is specified for each class. The complete assembly is mounted in a test frame that simulates the installation conditions, including all fixings and perimeter seals.

After testing, the product is assessed for two outcomes. First, whether the protected face was penetrated (pass or fail). Second, whether material splintered from the protected face during the test, which determines the S or NS suffix. An NS (no spall) result is the higher classification and is required wherever personnel will be located directly behind the product.

FB Classifications: Threat Levels Explained

The FB classification scale runs from FB1 (low-powered rimfire rifle) through to FB7 (armour-piercing rifle). Each class represents a specific weapon, calibre, bullet type, mass and reference impact velocity. The scale is not linear in terms of penetration energy: the jump from FB4 to FB5 represents a significant increase in threat, and FB7 (7.62 x 51mm AP with a hardened steel core) represents one of the most demanding civilian architectural ballistic tests in existence.

All velocities are reference impact velocities at the test specimen face, not muzzle velocities at the firearm. For FB4 (.44 Magnum) and FB6 (7.62 x 51 NATO), the test protocol requires a preliminary trial at the class below (FB3 and FB5 respectively) before the primary test is conducted, providing an additional layer of confidence in baseline performance.

Premier Security's Confirmed Ballistic Ratings

Premier Security's bullet resistant door systems have been independently tested at D J Goode of Suffolk and confirmed to prevent perforation at FB4, FB6 and FB7 classification ammunition. Following the standard FB7 test with 7.62 x 51mm AP ammunition, the system was subjected to further testing using Swiss-P 194g AP rounds and continued to perform. The system simultaneously achieved the LPS 1175 E10 security rating during the same testing programme, confirming combined ballistic and forced entry performance from a single certified product.

Premier Security's bullet resistant window systems have been independently tested and confirmed to FB4 and FB6 classification levels, with spall resistance verified on all independent glass layers within the assembly.

Premier Security's glazed curtain wall and modular walling system achieves FB7 ballistic performance alongside EXV10 blast resistance and a U-value of 0.5, making it one of the most comprehensively certified combined-threat facade systems available from a UK manufacturer.

S and NS Spall Classification

Every EN 1522 / EN 1523 test result carries a suffix indicating what happened to the protected (interior) face of the assembly during testing. This suffix is as important as the FB class number and must be included in any complete ballistic specification.

• S (Spall): Material splintered from the protected face during testing. The assembly prevented perforation but produced secondary fragmentation on the protected side. Acceptable for standoff or unoccupied-space applications where no person sits directly behind the line of fire.
• NS (No Spall): The protected face remained intact throughout testing. No fragmentation entered the protected space. Required for all applications where personnel are present directly behind the assembly.

A product specified as FB6 NS has been proven to stop 7.62 x 51 NATO ammunition without producing splinter hazard on the interior face. FB6 S has stopped the same round but produced fragmentation. For occupied buildings, NS is the standard requirement.

EN 1063: Understanding Glass-Only Ballistic Ratings

EN 1063:1999 is the European standard for testing glass and glass-clad polycarbonate composites against ballistic attack. It tests a 500mm x 500mm glazing sample mounted in a rigid test frame and produces BR1 to BR7 ratings (rifle and handgun threats) alongside SG1 and SG2 for shotgun threats. The calibres, velocities and test ranges used in EN 1063 match those in EN 1522/1523, allowing the glazing rating to be paired with the assembly rating.

EN 1063 is primarily used for glazing material qualification. A BR rating certifies the glass element alone in an idealised rigid frame. It does not certify how that glass will perform when installed in a real frame subject to real fixings and building movement. The complete assembly performance is tested under EN 1522/1523, which is the correct reference for project specifications.

Glass thicknesses shown are typical examples and will vary by manufacturer and interlayer specification. A BR7 glazing build-up typically runs to approximately 77mm in total thickness, comprising multiple laminated glass layers and polycarbonate or polyurethane interlayers designed to absorb and arrest the projectile.

When specifying a complete bullet resistant product, always confirm both the assembly rating (FB) and the glazing rating (BR). A product described only as "BR6 glazing" has a rated glass element but no certified frame, fixing or assembly performance. A product described as "FB6 NS" has been tested as a complete system and the full assembly is certified.

UL 752 and NIJ 0108.01: US Ballistic Standards for Reference

Specifiers working on embassy, diplomatic facility or US government projects may encounter UL 752 or NIJ 0108.01 ratings in project documentation. These are US standards and are not directly interchangeable with EN 1522/1523 FB ratings. This section explains what each standard covers so that specifiers can interpret them correctly when they appear in a specification.

UL 752: Bullet-Resisting Equipment

UL 752 is published by Underwriters Laboratories and covers bullet-resisting equipment including glazing, walls, doors and louvres for architectural applications. It uses a Level 1 to Level 10 scale where each level specifies a weapon, calibre, bullet type and number of shots. Unlike the EN 1522 scale, UL 752 levels are not strictly progressive from lowest to highest threat. Levels 1 to 3 broadly address handgun threats. Level 8 addresses a 7.62 x 39 (AK-style) rifle threat. Levels 6 and 7 address submachine gun scenarios. Always confirm the specific level and threat profile when interpreting a UL 752 specification.

NIJ 0108.01: Ballistic Resistant Materials

NIJ 0108.01 was developed by the National Institute of Justice primarily for armour and ballistic resistant materials. It uses Roman numeral levels (I, IIA, II, IIIA, III, IV) and is sometimes referenced in architectural contexts, particularly for standalone ballistic panels. It is distinct from NIJ body armour standards that use the same Roman numeral notation but address different threat profiles. For architectural building products in UK and European projects, EN 1522/1523 is the appropriate primary reference.

Why Independent Ballistic Testing Matters

Ballistic resistance cannot be calculated or estimated. A product must be physically fired upon by an independent accredited test laboratory using specified ammunition before any ballistic rating can be legitimately claimed. Premier Security does not self-certify. All ballistic ratings are obtained through testing by D J Goode of Suffolk, an independent UK ballistic test laboratory, and every rated product is supported by a formal test report that can be provided to specifiers, project managers, security consultants and government bodies as part of the product submission.

What Independent Testing Provides

• A verified ballistic rating from an independent accredited UK test facility
• A formal test report documenting the exact configuration tested, ammunition used and outcome achieved
• Confidence for specifiers, clients and insurers that performance is proven rather than claimed
• A precise scope of supply covering frame, glazing build-up, fixings and hardware
• Traceability for insurance, regulatory or procurement audit purposes
• An NS spall classification confirming the protected face remained intact

Ballistic, Blast and Forced Entry: Combined Protection from a Single Product

Facilities that require ballistic protection frequently also require protection against forced entry and, in many cases, blast. Critical national infrastructure sites, embassies, military installations and government buildings regularly specify products independently certified across all three disciplines. Specifying a single product that holds all required certifications eliminates the risk of incompatible components from different manufacturers and ensures the full security envelope is covered by verified test evidence.

Premier Security manufactures products that can hold simultaneous independent certification to:

• Ballistic resistance to EN 1522 / EN 1523 (FB4, FB6 and FB7, including armour-piercing)
• Forced entry resistance to LPS 1175 (SR2 to SR5, B3, C5, D10 and E10 classifications)
• Blast resistance to ISO 16933 (EXV10, EXV12 and EXV25) and GSA-TS01:2003
• Fire resistance to EI 60 and E90 classifications

Each certification is obtained through separate independent testing. A combined rating on a single product confirms that it has been verified against each threat individually, not that one certification implies another. Premier Security's glazed curtain wall and modular walling system is one of the few products available from a UK manufacturer certified to FB7 ballistic and EXV10 blast simultaneously, with a U-value of 0.5.

For further information on blast ratings, see our Blast Resistance guide. For forced entry ratings, see our LPS 1175 guide.

Frequently Asked Questions: Bullet Resistant Products

Related Premier Security Ballistic & Blast Resources

• Bullet Resistant Doors — EN 1522 FB4, FB6 and FB7 independently tested
• Bullet Resistant Windows — EN 1522 FB4 and FB6, spall resistant
• Bullet Resistant Glass — independently tested glazing systems
• Ballistic Curtain Walling — FB7 ballistic and EXV10 blast dual-certified facade systems
• Ballistic, Blast, Security and Fire — combined certified systems
• Blast Resistance — ISO 16933 EXV and GSA-TS01:2003 ratings explained
• LPS 1175 Security Ratings — forced entry resistance explained
• Contact Premier Security Ballistic & Blast — technical consultation and project enquiries