Short answer. The Regulatory Reform (Fire Safety) Order 2005 requires fire doors to be kept in efficient working order, but the specific tolerances people check against, gap widths, hinge numbers, glazing type, come from BS 8214:2016 and the individual door's certification, not from the Order itself. Residential buildings over 11 metres have additional statutory check frequencies under the Fire Safety (England) Regulations 2022.
What fire doors actually do
A fire door has one job: to contain fire and smoke for a specified period. A standard FD30 fire door provides 30 minutes of fire resistance, an FD60 provides 60 minutes. During that time the door holds back flames, heat and smoke, keeping escape routes clear and giving occupants time to get out.
Without fire doors, a fire that starts in one room can spread through a building within minutes, and smoke can fill corridors and stairwells almost as fast. A fire door only delivers that protection if it is correctly installed, properly maintained, and kept closed.
What the law requires, and what the standards require
Article 17 of the Regulatory Reform (Fire Safety) Order 2005 requires the responsible person to ensure that fire safety measures, fire doors included, are subject to a suitable system of maintenance and are maintained in efficient working order and in efficient working condition. The Order does not itself specify gap widths, hinge counts or glazing types.
Those specifics come from BS 8214:2016 (the code of practice for fire door assemblies) and from the certification of the individual door set, which is what a fire door needs to comply with to remain "as tested". A door's certificate, where one exists, takes precedence over general guidance for that specific door.
The tolerances people usually check
Under BS 8214 and typical door certification: gaps at the head and jambs are usually around 3mm when the door is closed. The threshold (bottom) gap is different: where the door has no smoke seal, a larger gap of roughly 8 to 10mm can be acceptable; where a smoke seal is fitted, the gap needs to be smaller, generally in line with the door's certificate. Intumescent strips and smoke seals must be intact and unobstructed, glazing must be fire-rated to the door's specification, and hinges must match what the certificate requires, commonly three hinges for a standard FD30 door.
Signage is covered by BS 5499 for fire door signs such as "Fire door keep shut", and a certified door should carry a permanent marking, typically a BWF-Certifire or BM TRADA plug or label, confirming its rating and that it has not been substituted.
Additional duties for residential buildings over 11 metres
The Fire Safety (England) Regulations 2022 added specific check frequencies for multi-occupied residential buildings over 11 metres in height: responsible persons must arrange quarterly checks of fire doors (including self-closing devices) in communal areas, and use best endeavours to carry out annual checks of flat entrance doors. These duties sit alongside, not instead of, the general FSO article 17 maintenance duty, and they do not apply to buildings under that height threshold.
The most common problems
- Doors propped open. A fire door propped open is not a fire door, it is a hole in your fire compartmentation. If doors need to be held open for operational reasons, fit hold-open devices linked to the fire alarm that release automatically when the alarm activates.
- Missing or damaged intumescent strips. These expand when exposed to heat, sealing the gap between door and frame. If they are painted over, missing, or the wrong type for the door, it will not perform to its rating.
- Failed self-closing devices. The closer must pull the door fully shut into the frame every time, from any angle. A door that sticks, bounces back, or only closes to within a few inches of the frame needs its closer adjusted or replaced.
- Excessive or incorrect gaps. Gaps larger than the door's certificate allows let smoke through and defeat the point of the door, whether that is a 3mm perimeter gap or a threshold gap that should be smaller because a smoke seal is fitted.
- Unauthorised modifications. Cat flaps, letterboxes, extra locks, non-fire-rated glazing, or ventilation grilles added without following the door manufacturer's specification compromise its fire rating.
- Wrong furniture. Standard hinges instead of fire-rated hinges, or plastic handles instead of fire-rated ironmongery. Every component on a fire door needs to be compatible with its certification.
How to check your fire doors
A basic fire door check does not need specialist equipment. Walk up to each fire door and check the following:
- Does it close fully into the frame under its own power?
- Is the self-closing device working correctly?
- Are the intumescent strips and smoke seals present and intact?
- Are the gaps around the door within the tolerances on its certificate?
- Does the hinge count and type match the certificate?
- Is the door free from damage, warping or unauthorised modification?
- Does it carry a certification plug, label or other marking confirming its rating?
Some issues, adjusting a closer, replacing a missing seal, are quick fixes. Others, a damaged door or incorrect glazing, need a fire door specialist.
The bigger picture
Fire doors are part of a wider compartmentation strategy: walls, floors, ceilings and doors work together to divide a building into fire-resistant sections. If any element fails, the strategy is compromised. A fire risk assessment includes a visual, sampled check of fire doors as part of the wider assessment, alongside escape routes, detection and management arrangements, though it is not a substitute for a full engineering survey of every door where one is needed.
Guidance on maintaining fire doors and other fire precautions in efficient working order is set out in the Regulatory Reform (Fire Safety) Order 2005, available from legislation.gov.uk.