FD30 or FD60: Which Fire Door Does Your Building Need?

What the numbers mean

The number is the time, in minutes, that a complete doorset held back fire in a standard test. FD30 is 30 minutes and FD60 is 60. The S suffix means the door also has smoke seals that slow cold smoke getting round the edges, which matters because smoke usually reaches people before flames do.

Who decides which you need

Not the door supplier. The rating comes from the building's fire strategy or your fire risk assessment, based on what the door protects. As a rough guide:

• FD30 or FD30S is typical for doors onto escape corridors, kitchens and many flat entrance doors.
• FD60 is used where a longer protection time is needed, such as some stair enclosures, plant rooms and risky storage.

If your assessment does not say, ask the assessor rather than guessing.

Why fitting decides whether it works

A certified door can fail badly if it is hung wrongly. The gaps round the edge must be within the maker's limits, intumescent strips must be the right size and in the right place, the frame must be fixed and sealed into the wall with fire-rated material, and every piece of hardware must be approved for that door. Cutting in a new lock with an ordinary router or adding a cat flap can undo the rating.

Self-closing and hold-open devices

Most fire doors must close fully by themselves. Doors wedged open are one of the most common faults inspectors find. Where a door needs to stay open in normal use, fit a device that releases it when the fire alarm sounds.

Your responsibilities

Under the Fire Safety Order, the responsible person (usually the employer, owner or managing agent) must keep fire doors in working order. In buildings with flats above shops, shared stairs and flat entrance doors need particular attention, and taller residential buildings have specific inspection duties.