Do I need a fire door, and what does FD30 mean?

Fire doors are one of the few pieces of household ironmongery with a life-safety function, and they are also one of the most commonly got wrong. Understanding what the rating means and what the assembly consists of makes it obvious why a fire door bought online and hung on ordinary hinges is not a fire door at all.

Safety

Step by step

1. Understand what the rating measures.An FD30 doorset has been tested to hold back fire for thirty minutes under standard test conditions. FD60 is sixty. The suffix S, as in FD30S, indicates the doorset also restricts the passage of cold smoke, which needs smoke seals as well as intumescent ones.
2. Recognise that it is a doorset, not a door.The certification covers the leaf, the frame, the intumescent seals in the leaf or frame, the hinges, the latch or lock, the closer where required and the glazing where fitted. Substituting any of those for something uncertified breaks the performance.
3. Know the common domestic situations.A loft conversion generally requires a protected escape route, which usually means fire doors to the rooms opening onto the stair. A door between a house and an integral garage is normally required to be fire resisting. Flats have requirements both to the flat entrance door and internally. Some houses of three or more storeys have requirements at other doors.
4. Check what applies to your property and nation.Building regulations are devolved and the requirements differ between England, Scotland, Wales and Northern Ireland. Check the guidance for your nation, or ask building control — this is precisely the kind of question they answer routinely.
5. Look for the certification on an existing door.Certified fire doors carry a label or a colour-coded plug, usually on the top edge or the hinge edge. If you cannot find one, you cannot assume the door is rated, no matter how heavy it feels.
6. Understand the gaps.Fire door performance depends on the gap around the leaf being within a tight tolerance so the intumescent seal can expand and close it. Too large and the seal cannot bridge it; too small and the door binds. The manufacturer's instructions state the range.
7. Understand the seals.Intumescent strips expand in heat to seal the gap. Combined intumescent and smoke seals add a brush or fin that blocks cold smoke, which is what actually kills people. Painted-over, damaged or missing seals are the most common defect found on domestic fire doors.
8. Understand the hardware requirement.Hinges must be of the correct grade, usually three per door, and CE or UKCA marked for fire doors. Locks, latches and any letterplate must be fire rated. A closer is required in some situations and not others, and where required it must actually close the door onto the latch from any angle.
9. Do not trim beyond the stated allowance.Certified doors state a maximum amount that may be removed from each edge. Exceeding it invalidates the certification, and on many doors it also cuts into the intumescent core.
10. Keep the paperwork.Certificates, the manufacturer's fitting instructions and the building control completion certificate for the work. This is one of the things a buyer's solicitor asks about on a loft conversion, and the absence of it is expensive to resolve later.

Questions people ask