fire_safety8 min readUpdated 2026-10-30

Specifying Fire-Resistant Glass Screens & Doors to Approved Document B

Essential compliance rules, classification distinctions (E vs EW vs EI), and system-level certification requirements for commercial fire compartmentation.

Executive Answer & Core Principle

Fire-resistant glass cannot be specified as a standalone product. UK Building Regulations Approved Document B and BS EN 13501-2 mandate that fire safety is achieved only by a tested and certified "complete glazed system" — encompassing the approved glass, certified fire-rated timber/steel/aluminium frames, verified intumescent glazing tapes, fire-rated silicone, and tested mechanical anchors.

1. Decoding Classifications: E vs EW vs EI

The European fire classification framework categorises performance into three distinct tiers: (E) Integrity — prevents flames and hot gases from penetrating, but allows radiant heat to pass through; (EW) Radiation Control — maintains integrity while reducing transmitted radiant heat to < 15 kW/m² on the unexposed face; (EI) Thermal Insulation — maintains integrity AND completely restricts conductive/radiant temperature rise to an average of ≤ 140°C above ambient.

Engineering Takeaways:

E (Integrity only): Suitable only where radiant heat does not threaten escape routes (e.g. high-level transom windows)

EW (Radiation): Often specified for boundary protection to prevent ignition of adjacent buildings

EI (Full Insulation): Mandatory on protected fire escape corridors, fire stairwells, and areas where people remain in close proximity to the glass

2. The Danger of Untested Substitutions

A catastrophic and frequent error on commercial sites is the substitution of standard toughened safety glass for fire-rated glass, or swapping the tested frame profile for a generic unrated aluminium channel. Standard toughened glass explodes within 3 to 6 minutes of fire exposure due to thermal stress differentials. Never accept fire glass without a matching Warringtonfire, Certifire, or IFC third-party system field of application certificate.

3. Fire Glass System Specification Checklist

Prior to placing an order, confirm: (1) Fire rating duration (30, 60, 90, or 120 minutes); (2) Integrity vs Insulation performance level; (3) Framing material compatibility; (4) Impact safety classification (BS EN 12600 Class 1B1 required for door vision panels); and (5) Intumescent tape compatibility stated in the test report.

Engineering Takeaways:

Always request the complete Test Report or Field of Application (FOA) assessment document

Check maximum certified pane dimensions; exceeding tested height/width invalidates the fire certificate

Verify orientation requirements (some fire glasses are fire-direction specific; ensure symmetrical EI where required)

Statutory UK Regulatory Context

UK Approved Document B (England & Wales), Section 2 of Scottish Building Standards Technical Handbooks, and BS 9999.

Technical Limitations:Technical guidelines reflect general UK building regulation principles; local Building Control Officer (BCO) or Fire Engineering consultant approval is required for all project-specific installations.

Related Material Specifications

Fire Resistant-Glass →Toughened Glass →Laminated Glass →

Recommended Next Step

GlassSuppliers.co.uk

Engage accredited fire screen contractors on GlassSuppliers.co.uk who provide full system conformity certification.

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