Fire door glossary

56 fire door terms, explained in plain English.

Fire door

A door designed, tested and installed to resist the passage of fire for a set time when closed, as part of a building's fire strategy.

Fire doorset

A complete fire door assembly supplied as one unit: leaf, frame, seals and hardware, tested together.

Door leaf

The opening part of a door, as distinct from the frame.

FD30

A fire door designed to resist fire for 30 minutes in a standard fire test.

FD60

A fire door designed to resist fire for 60 minutes in a standard fire test.

FD30S / FD60S

A fire door that also restricts the passage of cold smoke, usually with smoke seals and a controlled threshold gap.

Intumescent strip

A strip in the edge of a door or frame that expands in heat to seal the gap around the leaf during a fire.

Smoke seal

A brush, fin or blade seal that blocks cold smoke before an intumescent strip reacts.

Self-closing device

A closer that returns a fire door to the fully closed and latched position after it has been opened.

Overhead closer

A surface-mounted closer fixed to the head of the door or frame with an arm.

Concealed closer

A closer housed within the door leaf or frame, which needs specific fire test evidence for the door type.

Free-swing closer

A closer that lets a door move freely in normal use and closes it when the fire alarm activates.

Hold-open device

A device that holds a fire door open and releases it on fire alarm activation.

Door gap

The clearance between the door leaf and its frame, or between the leaf and the floor.

Threshold gap

The gap under a door leaf, also called the undercut.

Meeting stiles

The two vertical edges where the leaves of a pair of doors meet.

Lipping

A strip of hardwood fixed to the edge of a door leaf, sometimes used to correct gaps where the door's evidence allows.

Rebate

The recess in a door frame that the leaf closes against.

Door stop

The part of the frame the leaf closes against, forming the rebate.

Vision panel

A glazed opening in a door leaf so people can see through it.

Glazing bead

The strip that holds glass in place in a door; fire doors need fire-rated beads and fixings.

Integrity

A fire door's ability to stop flames and hot gases passing through.

Insulation

A fire door or glazing system's ability to limit heat transfer to the unexposed side.

Air transfer grille

A ventilation grille in a door or wall; in fire doors it must close in a fire, usually with intumescent material.

Certification label

A label or plug, often on the top or hinge edge, showing the door was made under a third-party certification scheme.

Test evidence

The fire test reports and assessments that show how a door construction performed and what it can be used with.

Field of application

The range of sizes, hardware and variations a door's test evidence covers.

Responsible person

The person or organisation with legal duties for fire safety in a building, typically the employer, owner or person in control of the premises; managing agents often act on their behalf.

Fire risk assessment

A documented assessment of fire risks in a building and the measures needed, including fire doors.

Regulation 10

The part of the Fire Safety (England) Regulations 2022 requiring quarterly communal fire door checks and annual flat entrance door checks in residential buildings with storeys over 11 metres.

Fire Safety Order

The Regulatory Reform (Fire Safety) Order 2005, the main fire safety law for non-domestic premises and common parts in England and Wales.

Fire Safety Act 2021

An Act that clarified the Fire Safety Order applies to the structure, external walls and flat entrance doors of multi-occupied residential buildings.

Building Safety Act 2022

The Act that created the new building safety regime and strengthened duties under the Fire Safety Order.

BS 8214

The British Standard code of practice for fire-resisting and smoke control doors; the current edition is BS 8214:2026.

BS EN 1634-1

The European fire resistance test standard for doors and shutters.

BS 476-22

The older British fire resistance test for non-loadbearing elements, still referenced for many existing doors.

BS EN 13501-2

The classification standard for fire resistance, using classes such as E30 and EI 30.

BS EN 1154

The standard for controlled door closing devices.

BS EN 1155

The standard for electrically powered hold-open devices for swing doors.

BS EN 1935

The standard for single-axis hinges, used to specify hinges suitable for fire doors.

BS EN 1125

The standard for panic exit devices operated by a horizontal bar.

BS EN 179

The standard for emergency exit devices operated by a lever handle or push pad.

Fire stopping

Sealing gaps and openings in fire-resisting walls and floors, including the gap between a door frame and the wall.

Compartmentation

Dividing a building into fire-resisting compartments so fire and smoke are contained.

Progressive horizontal evacuation

Moving people behind fire doors into an adjacent compartment, common in hospitals and care homes.

Protected route

An escape route enclosed by fire-resisting construction, such as a protected stair.

Final exit

The point where an escape route leaves the building to a place of safety.

Cross-corridor door

A fire door across a corridor that divides it into sections to limit smoke spread.

Flat entrance door

The front door of a flat opening onto a common corridor or stair, usually required to be a fire door.

Common parts

Corridors, stairs, lobbies and other areas shared by residents of a building.

Best endeavours

Under regulation 10, taking reasonable steps to gain access to check flat entrance doors and keeping evidence where access is not possible.

Remedial works

Repairs carried out to put right defects found in an inspection or fire risk assessment.

Door register

A record of every fire door in a building with its reference, location, specification and history.

Defect grading

Ranking defects by urgency, from immediate risk to planned maintenance.

Kick plate

A protective plate on the lower face of a door; on fire doors its size and fixing must be within the door's evidence.

Letter plate

A letter box in a door; on flat entrance fire doors it must be fire-rated.