Fire-rated glazing

The rating belongs to the whole assembly, not the glass

This is the single most misunderstood point in fire glazing. An EI60 pane in an untested frame with the wrong seals and the wrong fixings is not EI60 — it has no rating at all. The test evidence covers the exact combination of glass, frame, beads, gaskets, fixings and maximum pane size.

Substituting any element voids the evidence. We install to the tested specification and hand over the certification that names it, because at building control sign-off or after an incident that paperwork is the only thing that counts.

Integrity, insulation and why EI costs more than E

E means the assembly holds back flame and hot gases. EW adds a limit on the heat radiating through, so people can pass closer to it. EI adds insulation — the unexposed face stays cool enough that you could stand against it.

EI is what protected escape corridors normally need, and it is materially more expensive because it needs intumescent layers that expand and opacify in a fire. Specifying EI where E would do is one of the most common ways to waste money on a project.

Where fire glazing usually gets specified

Protected stairwells and lobbies, cross-corridor screens, atrium separation, plant and electrical rooms, and any glazing that forms part of a compartment line. In refurbishment, the most common trigger is a change of use or a new fire strategy identifying a compartment wall that was never rated.

We work from the fire strategy rather than guessing. If there isn't one, that is the thing to resolve before the glazing is priced.