Fire-rated glass guide
E, EW and EI in plain English — what the letters mean, how long the ratings last, and how to record an existing project requirement and review complete-system evidence.
Fire-rated glass is tested to hold back flames, smoke, heat or all three for a set number of minutes. A rating has two parts: a letter (E, EW or EI) describing what the glass resists, and a number (30, 60, 90, 120) saying how many minutes it must hold that performance in a test furnace.
E (integrity) is the basic level — the glass stays in place and stops flames and smoke for the rated time, but heat still radiates through. EW adds a radiation limit: the panel also reduces the heat felt on the far side. EI is the full package — integrity plus insulation, so the temperature rise on the unexposed side is limited by the classification criteria. This does not independently approve an escape route or installation.
Decide the rating your building needs first (building control or the fire strategy will say), then choose a system supported by the appropriate evidence. A pane alone does not qualify the frame, seals, fixings or aperture. BS 476 integrity/insulation minutes are recorded under their test regime and are not automatically EN 13501 classifications.
Record the project fire requirement
Enter an existing requirement from the project designer or authority. This guide cannot determine the required class or select an approved installation.
Fire requirement unknown — obtain project fire strategy; Unknown — project designer to confirm
England guidance removes national BS 476 fire-resistance classes on 2 September 2029, separately from the 2025 reaction-to-fire/roof changes. Confirm project jurisdiction, applicable guidance and fire strategy. Government transition dates ↗
Rating classes at a glance
Integrity for the classified duration. It does not establish radiation control or insulation.
The complete system and classification report determine E performance.
Integrity plus a radiation limit for the classified duration. EW is distinct from E and from EI.
Check radiation performance in the system classification report.
Integrity plus insulation for the classified duration. A BS 476 integrity/insulation pair alone is not an EN 13501 EI classification.
Specify class and minutes from the project fire strategy.
Manufacturer location/exposure terminology, separate from fire-resistance class. Confirm the specific glass, system and installation conditions.
Internal/external suitability cannot be inferred from the letters E, EW or EI.
Browse recorded fire evidence
Candidate models, lowest indicative price first. The performance a system actually achieves depends on how it is used — internal or external, door, screen or double-glazed unit, and the frame system. Check test regime, source revision and full system conditions on the detail page.
Need a price for fire-rated glass?
Request a quote on any glass with your exact size — no account needed.
Browse the fire-rated glass reference