Fire door safety
A fire door held open with a wedge is not a fire door — it is an open hole. This guide covers how to check a fire door is working, what the key faults are, inspection requirements, and what the law requires from landlords, employers, and responsible persons.
Key rule
A fire door only works when it is closed and latched. The self-closing device, intumescent seals, and rated frame work as a system — damage or remove any element and the resistance rating is void.
Inspection checklist
Six-point fire door check
Self-closing works from any angle
Open to 5°, release — the door must latch completely without help.
Gap around the leaf ≤ 3 mm
Use a £1 coin (~3 mm) as a go/no-go gauge around all four edges.
Intumescent seals intact
Strips should be continuous with no cuts, gaps, or sections pulled away.
Smoke seals present (FD30S/FD60S)
Brush or fin seals on the frame stop cold smoke — different from intumescent strips.
No unauthorised modifications
No holes, cat flaps, extra locks, or glazing not in the original specification.
Certification label present
BM TRADA Q-mark or equivalent on the top edge confirms the door is rated.
What a fire door actually does
A fire door does two things: it resists fire (preventing flames and hot gases from spreading) and it resists smoke (keeping escape routes clear). The fire resistance comes from the rated door leaf and frame assembly. The smoke resistance — marked by an "S" suffix (FD30S) — comes from cold-smoke seals, typically brush or rubber fin seals fitted in the frame rebate. Most fire doors in residential and commercial buildings should be FD30S as a minimum.
The flashover research from NIST shows that modern furnished rooms can reach untenable conditions in as little as three to five minutes. A correctly fitted FD30S door buys a minimum of thirty minutes — time for occupants to escape and emergency services to respond. That protection disappears the moment the door is wedged open.
Common faults and how to spot them
The most common fire door defects in UK enforcement notices are: doors held open with wedges or furniture; damaged or missing intumescent strips (often caused by painting over them, which can prevent them expanding); door closers adjusted too weak to pull the door shut; and gaps exceeding 3 mm around the door leaf. In multi-storey residential buildings, flat entrance doors are particularly important — they are the boundary between a private unit and a protected escape route.
The coin gap test
Run a £1 coin (approximately 3 mm thick) around the gap between the door leaf and frame on all four sides. If the coin slides through easily, the gap is too large. This is not a pass/fail test on its own — the door also needs proper seals, a working closer, and a complete frame — but it is a quick visual indicator of a significant defect.
Legal obligations for responsible persons
In England, the Fire Safety (England) Regulations 2022 require responsible persons to inspect communal fire doors in multi-occupied residential buildings quarterly (or monthly for buildings over 11 m). Flat entrance doors must be inspected annually. Building owners must also provide residents with fire door safety information at least every 12 months. These requirements supplement, and do not replace, those under the RRO 2005. For tenants in affected buildings, our fire safety for renters guide explains the practical steps you can take.
Do not paint over fire door seals
Intumescent strips and smoke seals must never be painted over. Paint can fuse the intumescent material to the groove, preventing it from expanding when exposed to heat. If a fire door assembly has been repainted, the seals should be inspected — and replaced if there is any evidence of paint bridging the gap between the strip and the door or frame. This is one of the most frequently missed defects during inspections.
Fire door FAQ
Questions about fire door safety
A fire door is a purpose-built assembly designed to resist the passage of fire and smoke for a rated period — typically 30 minutes (FD30) or 60 minutes (FD60) in the UK, or 20, 45, 60, or 90 minutes under US NFPA 80. The rating applies to the complete assembly: door leaf, frame, seals, hinges, and hardware. Replacing any component with a non-rated equivalent invalidates the rating. See our fire door glossary entry for the full technical definition.
No. Wedging a fire door open negates its entire purpose — a fire door only works when it is closed. In the UK, propping open a fire door in a workplace or multi-occupancy building is a breach of the Regulatory Reform (Fire Safety) Order 2005. The only acceptable way to hold a fire door open legally is with a certified electromagnetic hold-open device that releases automatically when the fire alarm activates. If you need a door open for ventilation or access, have an automatic release device fitted.
Key checks: the door should close fully and latch automatically from any open position; there should be no gap greater than 3 mm around the door leaf (4 mm at the bottom if there is no threshold seal); intumescent strips should be present and undamaged; the door closer should pull the door shut from 5° open without assistance. In the UK, all compliant fire doors should carry a BM TRADA Q-mark or equivalent certification label on the top edge or hinge side.
The Fire Safety (England) Regulations 2022 require responsible persons in multi-occupied residential buildings to check communal fire doors quarterly, and flat entrance doors annually. For workplaces, inspections should be defined in the fire risk assessment — typically quarterly for high-traffic doors, annually for low-use doors. Any defect (broken closer, missing intumescent seal, visible gap) should be repaired immediately. For context on your obligations as a renter or landlord, see our fire safety for renters guide.
Standard internal domestic doors are not fire doors and provide minimal fire resistance — typically less than five minutes. In a house, the building regulations do not generally require fire doors to individual rooms, though they are required on certain protected escape routes and between an integral garage and living space. In a house of multiple occupation (HMO) or converted flat, fire doors are required and must meet FD30S (30-minute fire and smoke resistance). Upgrading domestic doors to fire-rated equivalents is advisable, particularly on rooms containing sleeping occupants.