A fire door is a complete door assembly - door leaf, frame, and ironmongery - that has been tested to resist the passage of fire and smoke for a defined period. The rating is expressed as FD30 (30-minute resistance) or FD60 (60-minute resistance). The FD rating means the door, when correctly installed with appropriate intumescent seals and self-closer, will maintain its integrity (not burn through) and in smoke-rated versions (FD30S, FD60S) will also limit smoke passage for the rated period. Fire doors protect escape routes, allowing occupants time to evacuate before fire spreads.

Where are fire doors required in domestic properties?

Approved Document B requires fire doors in domestic properties in the following locations: between an integral garage and the house (FD30S minimum); on all rooms opening onto the protected staircase in a loft conversion (FD30S); in houses of three or more storeys, all habitable room doors opening onto the staircase must be FD30S; in flats, the front door and any door in the protected escape route must be FD30 or FD60 depending on building height. An FD30S door is required where smoke resistance is needed in addition to flame resistance - the S suffix indicates a smoke seal is included.

What makes a door a fire door?

A fire door's performance depends on the complete door set: the door leaf (typically solid core timber, composite, or steel, tested to BS EN 1634-1); the frame (rebated frame of adequate depth and density); intumescent seals in the door or frame edges that expand on heat to seal the gap; cold smoke seals (brush or rubber strips) if an S rating is required; and a self-closing device (overhead closer or concealed floor spring). All these components must be certified as part of a tested assembly - a tested fire door leaf in an unrated frame, or without intumescent seals, is not a fire door. Third-party certification (BM TRADA Q-Mark, Certifire) confirms the complete assembly is compliant.

Can you prop open a fire door?

No - propping a fire door open defeats its purpose and is illegal in all circumstances in commercial and multi-occupancy residential buildings. In a domestic house, a fire door propped open provides no protection. The self-closer is required specifically to ensure the door is always closed and the escape route protected. Electro-magnetic hold-open devices (which release automatically on fire alarm activation) are permitted in some commercial situations but must not be used in simple domestic fire door installations. If a fire door is too heavy to use comfortably, a lighter compliant alternative or an overhead closer with better backcheck adjustment should be specified - not removal of the closer.

Fire Safety noun

Fire Door

/ faɪə dɔː /

Also known as: FD30 door, FD60 door, fire-resisting door, fire door set

Definition

A fire door is a complete door assembly - leaf, frame, intumescent seals, smoke seals, and self-closer - tested and rated to resist fire for a defined period. FD30 resists fire for 30 minutes; FD60 for 60 minutes. The S suffix (FD30S) adds smoke resistance. Fire doors protect escape routes by buying time for evacuation. Required in domestic properties at garage-to-house openings, on staircase enclosures in loft conversions, and in houses of three or more storeys.

In practice

A fire door is only as good as its complete installation - the leaf, frame, intumescent seals, smoke seals, and self-closer must all be compatible and certified as a tested assembly. Intumescent seals (strips fitted in the door or frame edges that expand under heat to seal the gap) are critical - a fire door without intumescent seals is not a fire door. The gap between door and frame must be within the limits of the tested assembly, typically 3-4mm on the sides and top, and the threshold gap must be addressed with a drop-seal or threshold strip.

Self-closers are mandatory on fire doors - a door that is not self-closing provides no fire protection when left open. Overhead closers (surface-mounted or concealed) are standard for domestic and commercial fire doors. The door should close fully and latch without being pushed or held; if it requires effort to close, the closer needs adjustment or the door has dropped on its hinges. Three hinges are required for FD30 doors (not two). All fire door hardware (hinges, locks, closers) must be certified for use with fire doors - standard builders-merchant ironmongery is not rated.

Building Regulations

StandardBS EN 1634-1 - Fire resistance tests for door and shutter assemblies

Garage to houseFD30S required between integral garage and dwelling

Loft conversionFD30S on all rooms off protected staircase

3+ storey housesFD30S on all habitable room doors off staircase

Approved Document B (Fire Safety - Dwellings) specifies where fire doors are required in domestic properties. For a two-storey house without a loft conversion, fire doors are only required at the integral garage opening (if there is one). For a loft conversion creating a third storey, all room doors off the staircase (from ground floor to loft) must be FD30S fire doors with self-closers. Third-party certification (BM TRADA Q-Mark or Certifire) provides the most reliable evidence that a door set is compliant with the relevant standard - look for the certification label on the door top edge.

Full Building Regulations guidance

Fire Door

Just so you know...