FD30 and FD90 are both certified fire doorsets, rated to resist fire for at least 30 and 90 minutes of integrity respectively (broadly E30 and Per certified design under BS EN 13501-2). The difference is duration: FD90 holds the line for 90 minutes where FD30 holds it for 30. FD30 is specified for flat entrances, HMO and escape-route doors, corridors and most internal fire doors; FD90 for high-hazard compartmentation, significant compartment lines and industrial positions. The correct rating for any opening comes from the building's fire strategy and risk assessment, not a general rule.
FD30 vs FD90 at a glance
| FD30 | FD90 | |
|---|---|---|
| Fire resistance | 30 minutes | 90 minutes |
| EN classification | ≈ E30 (integrity) | Per certified design |
| Typical leaf | Typically 44 mm | Per certified design |
| Where it is specified | flat entrances, HMO and escape-route doors, corridors and most internal fire doors | high-hazard compartmentation, significant compartment lines and industrial positions |
When FD30 is the right choice
Specify FD30 where the fire strategy calls for 30minutes' integrity — flat entrances, HMO and escape-route doors, corridors and most internal fire doors. Stepping up to a higher rating than the strategy requires adds cost and weight without adding compliance; the rating should match the assessed risk at each opening.
When to step up to FD90
FD90 is specified where the fire strategy or Approved Document B demands 90 minutes rather than 30 — high-hazard compartmentation, significant compartment lines and industrial positions. At this rating the doorset construction is heavier and, above FD60, the design and glazing become more restricted; confirm what is achievable against the certified field of application.
Both figures describe integrity (E) — resisting flame and hot gases — not insulation (EI), which limits heat transfer and is separately tested. Leaf thicknesses are typical, not mandatory; the certified design governs. Also see FD30 vs FD60, the full range (FD30–FD120), or run the compliance checker.