Technical reference
The fire door glossary
Every term you'll meet in a specification, certificate or regulation — defined precisely enough to rely on.
Accountable person
Under the Building Safety Act 2022, the organisation or individual responsible for managing building safety risks in an occupied higher-risk building in England. Where several exist, a principal accountable person is identified. Duties include assessing building safety risks, registering the building and maintaining the golden thread of building information.
See also: Higher-risk building (HRB) · Golden thread · Responsible personAcoustic rating (Rw)
A single-number laboratory measure, in decibels, of how much airborne sound a building element such as a doorset reduces, derived under BS EN ISO 717-1. Higher Rw values mean better sound insulation. Flat entrance doorsets in England are commonly specified at around 29 dB Rw or higher alongside their fire rating.
See also: U-value · Drop-down seal · Fire doorsetAir transfer grille
A ventilation opening fitted in a fire door or wall, incorporating an intumescent block that expands under heat to seal the airway in fire. Only grilles covered by test evidence for the specific doorset should be used, because an unprotected ventilation opening destroys the fire resistance of the whole assembly.
See also: Intumescent seal · Letterplate · Vision panelApproved Document B
Statutory guidance to the Building Regulations in England covering fire safety, published in two volumes for dwellings and other buildings. It sets out where fire doors are needed and the ratings expected in given locations, and currently accepts fire door test evidence to either BS 476-22 or BS EN 1634-1.
See also: BS 476-22 · EN 1634-1 · Technical Handbook (Scotland)Architrave
The decorative moulding fitted around a door frame to cover the junction between frame and wall. On fire doors the architrave is not usually part of the tested assembly, but the frame-to-wall gap behind it must be correctly sealed with fire-stopping material in line with the installation instructions and BS 8214.
See also: Lipping · Gap tolerance · BS 8214Assessment
A professional judgement by a suitably qualified fire engineer or test body extending primary test evidence to cover a variation from the tested fire door design, such as a different size or item of ironmongery. Assessments must follow recognised field-of-application rules and cannot replace testing where evidence does not support the change.
See also: Primary test evidence · Field of application (DIAP and EXAP) · Third-party certificationBS 476-22
The historic British Standard fire resistance test for non-loadbearing elements, including fire doors, under which UK ratings such as FD30 and FD60 were established. Approved Document B in England currently accepts BS 476-22 evidence alongside the European test standard BS EN 1634-1, so both routes remain in use.
See also: EN 1634-1 · FD30 · Positive pressure testBS 8214
The British Standard code of practice for the installation of timber-based fire door assemblies. It covers fitting, gaps, sealing and ironmongery, and gives typical guidance of a 2-4 mm perimeter gap between leaf and frame, with threshold gaps set by the doorset specification and its supporting test evidence.
See also: Gap tolerance · Fire door assembly · ArchitraveBWF Fire Door Alliance
The British Woodworking Federation's third-party certification grouping for timber fire doors, formerly known as BWF-Certifire. Member doors carry traceable labels or colour-coded plugs linking each door to audited manufacture and fire test evidence, giving specifiers and inspectors assurance that the installed product matches what was actually tested.
See also: Certifire · Colour-coded plug · Third-party certificationCE and UKCA marking
Conformity markings showing a construction product has been assessed against an applicable standard and is supported by a Declaration of Performance: UKCA against British designated standards, CE against European harmonised standards. For doorsets, fire characteristics are declared under EN 16034, used alongside EN 14351-1 for external doorsets.
See also: Declaration of Performance (DoP) · Harmonised standard (hEN)Ceramic glazing
Fire-rated glazing made from glass-ceramic material with near-zero thermal expansion, able to withstand fire temperatures and thermal shock for long periods. It provides integrity (E) performance but transmits radiant heat, so it does not by itself give an insulation (EI) classification, and it must be installed with compatible intumescent glazing systems.
See also: Georgian wired glass · Vision panel · E, EI and EW classificationsCertifire
A third-party certification scheme for fire protection products, operated by Warringtonfire. Certifire-approved fire doors and doorsets are audited against their fire test evidence, with ongoing factory production control, and are identified through certificate listings and labels so installers and inspectors can verify the claimed rating of each door.
See also: BWF Fire Door Alliance · Q-Mark · Third-party certificationColour-coded plug
A small coloured disc inserted into the edge or top of a certificated fire door leaf, identifying its certified fire rating and manufacturer under schemes such as the BWF Fire Door Alliance and Q-Mark. The plug colours denote the rating and provide traceability to test evidence years after installation.
See also: BWF Fire Door Alliance · Q-Mark · Third-party certificationCompartmentation
The division of a building into fire-resisting compartments by walls and floors to limit the spread of fire and smoke. Fire doors are the moving parts of compartmentation: every opening in a compartment line must be protected by a door or shutter of equivalent fire resistance for the strategy to work.
See also: Fire resistance · Protected route · Means of escapeDeclaration of Performance (DoP)
The formal document a manufacturer must issue for a construction product placed on the market under a harmonised or designated standard. It states the product's declared performance characteristics, such as its fire resistance classification, and is the legal basis for applying CE or UKCA marking to a doorset.
See also: CE and UKCA marking · Harmonised standard (hEN)Door core
The internal construction of a fire door leaf that provides most of its fire resistance. Common cores include particleboard, solid or laminated timber, dowelled timber strips and mineral cores. Core type, density and thickness are fixed by the fire test evidence, so a core cannot be substituted without new evidence or assessment.
See also: Fire door leaf · Lipping · Primary test evidenceDrop-down seal
An automatic threshold seal mortised into the bottom edge of a door leaf. A plunger drops the seal to the floor as the door closes, blocking the threshold gap against cold smoke and sound. Used where smoke control or acoustic performance is required at the bottom of the door.
See also: Smoke seal · Gap tolerance · Acoustic rating (Rw)E, EI and EW classifications
The European fire resistance classes under EN 13501-2. E denotes integrity only, meaning the element stops flames and hot gases; EI adds insulation, limiting temperature rise on the unexposed face; EW limits radiated heat. EI is a stricter criterion than E, so an FD30 or E30 door must never be described as EI30.
See also: EN 13501-2 · FD30 · Fire resistanceEN 1154
The European standard for controlled door closing devices. Self-closers fitted to fire doors should be CE or UKCA marked to BS EN 1154, carry fire test evidence, and typically be set at power size EN 3 or above so the door reliably closes and engages its latch from any opening angle.
See also: Self-closing device · EN 1155 · Hold-open deviceEN 1155
The European standard for electrically powered hold-open devices for swing doors. Devices to BS EN 1155 hold a fire door open in normal use and release it on fire alarm activation or power failure so the self-closer can shut it. Wedges and unlisted retainers are never acceptable substitutes.
See also: Hold-open device · EN 1154 · Self-closing deviceEN 13501-2
The European classification standard for fire resistance test results. It translates tests such as EN 1634-1 into classes combining performance criteria (E, EI, EW) with minutes from 15 to 240, plus optional smoke classes Sa or S200. For example, E30Sa broadly corresponds to a UK FD30s smoke-control fire door.
See also: E, EI and EW classifications · EN 1634-1 · Smoke sealEN 1634-1
The European fire resistance test standard for door and shutter assemblies, adopted in the UK as BS EN 1634-1. A complete doorset is exposed to a standard heating curve in a furnace under positive pressure, and the result is classified under EN 13501-2 as E, EI or EW with a time rating.
See also: BS 476-22 · EN 13501-2 · Positive pressure testFD120
A UK fire door rating denoting 120 minutes of fire resistance, broadly equivalent to E120 under European classification. FD120 doorsets are specialist products using high-performance cores, specified for openings in compartment walls with the most demanding fire resistance requirements, such as separations between buildings or protection of high-hazard areas.
See also: FD90 · FD60 · CompartmentationFD30
A UK fire door rating denoting 30 minutes of fire resistance (integrity) when tested to BS 476-22, broadly equivalent to E30 under BS EN 1634-1 and EN 13501-2. FD30 doors typically use a 44 mm thick leaf and are the most common rating for flats, HMOs and internal escape routes.
See also: FD30s · FD60 · E, EI and EW classificationsFD30s
An FD30 fire door additionally fitted with smoke seals to restrict the spread of cold smoke, broadly equivalent to E30Sa or E30S200 under European classification. The lowercase 's' denotes smoke control, usually achieved with combined intumescent and smoke seals. Flat entrance doors and doors onto escape corridors are typically specified FD30s.
See also: FD30 · Smoke seal · Drop-down sealFD60
A UK fire door rating denoting 60 minutes of fire resistance, broadly equivalent to E60 under European classification. FD60 doors typically use a 54 mm thick leaf and are specified where compartmentation demands longer protection, such as doors to plant rooms, protected shafts and other higher-risk locations.
See also: FD30 · FD90 · Door coreFD90
A UK fire door rating denoting 90 minutes of fire resistance, broadly equivalent to E90 under European classification. FD90 doorsets use thicker or higher-performance cores than FD60 doors and are specified where compartment walls require extended fire resistance, typically in larger commercial, industrial or institutional buildings rather than housing.
See also: FD60 · FD120 · CompartmentationFDIS
The Fire Door Inspection Scheme, a UK certification scheme for fire door inspectors supported by the British Woodworking Federation. FDIS reported in 2021 that around 75% of more than 100,000 inspected fire doors did not meet required standards, evidence of widespread installation and maintenance failures across the UK building stock.
See also: NAFDI · Third-party certification · Regulation 10 checksField of application (DIAP and EXAP)
Rules defining how far fire test results can be applied beyond the exact specimen tested. Direct application (DIAP) covers permitted variations stated within the test standard itself; extended application (EXAP), under standards such as the EN 15269 series, allows wider variations justified by analysis. Together they set the limits of valid evidence.
See also: Assessment · Primary test evidence · EN 1634-1FIRAS
A third-party certification scheme for fire protection installers, operated by Warringtonfire. FIRAS-registered contractors are audited for competence in disciplines including fire door installation and maintenance, and samples of their work are inspected. Using certificated installers helps responsible persons demonstrate competence under the Regulatory Reform (Fire Safety) Order 2005.
See also: Q-Mark · Third-party certification · BS 8214Fire door assembly
A fire door built up from separately sourced components - leaf, frame, seals, glazing and ironmongery - brought together on site to achieve a fire rating, with timber assemblies installed to BS 8214. Unlike a doorset, the components were not necessarily manufactured and tested together, so compatibility with test evidence is critical.
See also: Fire doorset · Fire door leaf · BS 8214Fire door leaf
The openable panel of a fire door, excluding the frame, seals and ironmongery. A leaf alone has no fire rating: ratings such as FD30 apply only to the complete assembly or doorset. Leaf thickness is typically 44 mm for FD30 timber doors and 54 mm for FD60 timber doors.
See also: Fire doorset · Fire door assembly · Door coreFire doorset
A complete fire door unit - leaf, frame, seals and usually ironmongery and any glazing - manufactured and supplied from one source as a single tested product. Because every component matches the fire test evidence, doorsets offer the most reliable route to certified performance and are increasingly preferred over site-assembled fire door assemblies.
See also: Fire door assembly · Fire door leaf · Third-party certificationFire resistance
The ability of a building element to withstand a fully developed fire for a stated period, measured against criteria such as integrity, insulation and radiation in furnace tests like BS 476-22 or BS EN 1634-1. It is distinct from reaction to fire, which concerns how a material contributes to fire growth.
See also: Reaction to fire · E, EI and EW classifications · CompartmentationFire risk assessment (FRA)
The systematic assessment of fire risk in premises required by the Regulatory Reform (Fire Safety) Order 2005. The responsible person must record the significant findings, which should identify fire doors, their required ratings and their condition. FRA findings commonly drive fire door inspection, upgrade and replacement programmes in existing buildings.
See also: Responsible person · Regulatory Reform (Fire Safety) Order 2005 · Regulation 10 checksFire Safety (England) Regulations 2022
Regulations (SI 2022/547) made under the Fire Safety Order, in force from 23 January 2023. Regulation 10 requires quarterly checks of communal fire doors and annual best-endeavours checks of flat entrance doors in multi-occupied residential buildings over 11 metres in England, and residents must be given fire door information.
See also: Regulation 10 checks · Responsible person · Fire Safety Act 2021Fire Safety Act 2021
An Act clarifying that, for multi-occupied residential buildings, the Regulatory Reform (Fire Safety) Order 2005 applies to the building's structure, external walls and flat entrance doors. It removed long-standing ambiguity over whether flat entrance doors fell within the responsible person's fire risk assessment duties, paving the way for the 2022 Regulations.
See also: Regulatory Reform (Fire Safety) Order 2005 · Responsible person · Fire Safety (England) Regulations 2022Gap tolerance
The permitted gap between a fire door leaf and its frame or threshold. BS 8214 guidance for timber doors is typically 2-4 mm at the head and vertical edges, with threshold gaps set by the doorset specification. Excessive gaps let fire and smoke pass and are a leading cause of inspection failures.
See also: BS 8214 · Intumescent seal · Smoke sealGateway
One of three regulatory stop points for higher-risk buildings in England under the Building Safety Act 2022 regime: Gateway 1 at planning, Gateway 2 before building work starts and Gateway 3 before occupation. Work on a new higher-risk building cannot lawfully proceed past a gateway without Building Safety Regulator approval.
See also: Higher-risk building (HRB) · Golden thread · Accountable personGeorgian wired glass
Traditional fire-rated glass containing an embedded steel wire mesh that holds the cracked pane in place during fire, giving integrity-only (E) performance. Common in older fire doors, it provides no insulation against radiant heat and is increasingly replaced by clear ceramic or laminated intumescent glazing in new and upgraded doors.
See also: Ceramic glazing · Vision panelGolden thread
The digital record of building information required for higher-risk buildings under the Building Safety Act 2022. It must be accurate, kept up to date and accessible, covering design, construction and refurbishment - including fire door specifications and certification - so accountable persons can manage building safety throughout the building's life.
See also: Higher-risk building (HRB) · Accountable person · GatewayHarmonised standard (hEN)
A European product standard developed under the Construction Products Regulation whose citation makes CE marking possible for the products it covers. In Great Britain the parallel concept is the designated standard, which underpins UKCA marking. EN 16034 is the standard addressing the fire resistance and smoke control characteristics of doorsets.
See also: CE and UKCA marking · Declaration of Performance (DoP)Higher-risk building (HRB)
In England, a building at least 18 metres tall or with at least seven storeys, containing two or more residential units. Higher-risk buildings face the Building Safety Act 2022's most stringent regime: registration, accountable person duties, safety case reports, gateways for new buildings and the golden thread of building information.
See also: Accountable person · Gateway · Golden threadHMO (house in multiple occupation)
A property rented by three or more people forming more than one household who share facilities such as a kitchen or bathroom. Larger HMOs require licensing, and licence conditions informed by LACORS fire safety guidance commonly require FD30 or FD30s fire doors, usually self-closing, protecting the escape route.
See also: LACORS guidance · FD30 · Means of escapeHold-open device
A device that legally holds a self-closing fire door open and releases it when the fire alarm operates or power fails, allowing the closer to shut the door. Electrically powered devices conform to BS EN 1155; acoustic and free-swing variants also exist. Wedges and improvised hooks are never acceptable.
See also: EN 1155 · Self-closing deviceIntumescent seal
A strip of heat-reactive material set into the edges of a fire door leaf or frame that expands to many times its size at around 200°C, sealing the gap between leaf and frame against fire. Essential to modern fire door performance, it must match the size and position in the test evidence.
See also: Smoke seal · Gap tolerance · FD30LACORS guidance
The 2008 national fire safety guidance for certain existing residential premises, produced by LACORS with government and fire sector bodies. Widely used by councils for HMOs and shared houses, it sets risk-based expectations that commonly include FD30 or FD30s fire doors protecting the escape route in higher-risk layouts.
See also: HMO (house in multiple occupation) · FD30 · Protected routeLetterplate
An aperture and flap in a door for mail delivery. In a fire door, a letterplate is acceptable only where it is a tested, intumescent-protected unit covered by the doorset's fire evidence. Cutting an untested letterplate aperture into a fire door invalidates its certification and undermines its fire performance.
See also: Air transfer grille · Vision panel · Intumescent sealLipping
A hardwood strip bonded to the edges of a fire door leaf, protecting the core and allowing limited trimming to fit the frame. The test evidence and certification state the maximum trim allowance - often only a few millimetres per edge - beyond which the door's fire performance is compromised.
See also: Door core · Fire door leaf · Gap toleranceMeans of escape
The routes and exits by which occupants can evacuate a building safely in a fire. Fire doors defend the means of escape by holding back fire and smoke from corridors and stairways, and the Fire Safety Order requires responsible persons to keep escape routes and their doors maintained and available.
See also: Protected route · Compartmentation · Fire risk assessment (FRA)NAFDI
The National Association of Fire Door Inspectors, a UK membership body for fire door inspectors offering training, competence assessment and registration. Alongside FDIS-certificated inspectors, NAFDI-registered inspectors give responsible persons a route to demonstrably competent fire door inspection when discharging duties under the Fire Safety Order and the 2022 Regulations.
See also: FDIS · Regulation 10 checksNominal fire door
An older door with no test evidence that is judged, by its construction and condition, potentially capable of resisting fire for a period - for example a sound, solid timber door. A fire risk assessor may accept or upgrade nominal doors in lower-risk existing buildings, but they carry no certified rating.
See also: Notional fire door · Fire risk assessment (FRA)Notional fire door
An existing door accepted as providing a stated level of fire resistance because its construction matches a recognised historic specification, even though it was never tested to current standards. Fire risk assessments in older buildings frequently weigh upgrading notional doors with seals and closers against full replacement with certificated doorsets.
See also: Nominal fire door · Fire risk assessment (FRA) · Primary test evidencePAS 24
A UK security test standard for doorsets and windows, demonstrating resistance to the methods used by opportunist burglars. Flat entrance doorsets often need security as well as fire performance, so specifications commonly call for PAS 24 alongside FD30s, supporting Approved Document Q compliance and Secured by Design accreditation.
See also: Secured by Design · Fire doorsetPositive pressure test
A furnace test condition in which pressure inside the furnace exceeds ambient pressure over most of the door height, forcing hot gases through any gaps. BS EN 1634-1 fixes the neutral pressure plane at 500 mm above the notional floor, making it generally more onerous at the door head than BS 476-22.
See also: EN 1634-1 · BS 476-22Primary test evidence
Fire resistance test data obtained by testing an actual doorset specimen in a furnace to BS 476-22 or BS EN 1634-1. It is the foundation of every legitimate fire door rating: assessments and field-of-application extensions must trace back to primary evidence, and certification schemes audit products against it.
See also: Assessment · Field of application (DIAP and EXAP) · Third-party certificationProtected route
A corridor, lobby or stairway enclosed in fire-resisting construction that gives occupants a safe path to a final exit. Every door opening onto a protected route or protected stairway must be a fire door, typically FD30s, so the route remains passable while the building is evacuated.
See also: Means of escape · Compartmentation · FD30sQ-Mark
A third-party certification scheme operated by BM TRADA covering fire door manufacture, installation and maintenance. Q-Mark certified doors carry identifying plugs and labels traceable to audited factories and fire test evidence, while the installer and maintainer schemes certificate the competence of companies that fit and look after fire doors.
See also: Certifire · FIRAS · Colour-coded plugReaction to fire
How a material behaves in the early stages of a fire - its ignitability, flame spread and contribution to fire growth - classified in Europe from A1 to F under EN 13501-1. It is distinct from fire resistance, which measures how long a complete element such as a doorset withstands a developed fire.
See also: Fire resistance · EN 13501-2Regulation 10 checks
Fire door checks required by the Fire Safety (England) Regulations 2022 from 23 January 2023. In multi-occupied residential buildings over 11 metres in England, responsible persons must check communal fire doors at least every three months and use best endeavours to check flat entrance doors at least every twelve months.
See also: Fire Safety (England) Regulations 2022 · Responsible person · Self-closing deviceRegulation 38
A requirement of the Building Regulations 2010 in England that fire safety information about relevant building work be handed to the responsible person at completion or first occupation. This should include fire door locations, specifications and certification, providing the operational baseline for the building's ongoing inspection and maintenance regime.
See also: Golden thread · Responsible person · Fire risk assessment (FRA)Regulatory Reform (Fire Safety) Order 2005
The principal fire safety law for non-domestic premises and the common parts of residential buildings in England and Wales. It places duties on the responsible person, and Article 17 requires facilities including fire doors to be maintained in an efficient state, in efficient working order and in good repair.
See also: Responsible person · Fire Safety Act 2021 · Fire risk assessment (FRA)Responsible person
The person holding duties under the Regulatory Reform (Fire Safety) Order 2005 - typically the employer, building owner or managing agent in control of the premises. Responsible persons must assess fire risks, maintain fire doors and other fire safety measures, and in taller residential buildings carry out Regulation 10 door checks.
See also: Regulatory Reform (Fire Safety) Order 2005 · Regulation 10 checks · Accountable personSecured by Design
The official police security initiative for the UK, accrediting products and developments designed to reduce crime. Fire doorsets can hold Secured by Design accreditation where they combine certified fire resistance with tested security performance such as PAS 24, a pairing commonly specified for flat entrance doorsets in new housing.
See also: PAS 24 · Fire doorsetSelf-closing device
A controlled closing mechanism, conforming to BS EN 1154, that shuts a fire door fully into its frame from any open position. Most fire doors, including flat entrance doors, must be self-closing to protect anyone: a door wedged open or fitted with a broken or disconnected closer provides no protection.
See also: EN 1154 · Hold-open device · Regulation 10 checksSmoke seal
A flexible brush or fin seal fitted around a fire door to block cold smoke, which spreads long before heat activates intumescent seals. Smoke seals provide the 's' in FD30s ratings; the European equivalents are smoke classes Sa (ambient temperature) and S200 (up to 200°C), tested to EN 1634-3.
See also: Intumescent seal · FD30s · Drop-down sealTechnical Handbook (Scotland)
The statutory guidance supporting Scottish building regulations, published in domestic and non-domestic volumes. Its fire section sets Scotland's expectations for fire doors and compartmentation, differing in places from England's Approved Document B - a reminder that building and fire safety guidance is devolved across the four UK nations.
See also: Approved Document BThird-party certification
Independent, ongoing verification that a fire door product or installer consistently matches its fire test evidence, through initial testing, factory or site audits and traceable labelling under schemes such as BWF Fire Door Alliance, Certifire, Q-Mark and FIRAS. Not usually a legal requirement, but widely recognised best practice and increasingly specified.
See also: BWF Fire Door Alliance · Certifire · Q-Mark · FIRASU-value
A measure of the rate of heat transmission through a building element, expressed in W/m²K; lower values mean better thermal insulation. External fire doorsets and flat entrance doors opening onto unheated areas must balance thermal performance against fire, smoke, security and acoustic requirements within one certified product.
See also: Acoustic rating (Rw) · PAS 24Vision panel
A glazed aperture in a fire door leaf that lets people see through before opening, reducing collision risk and aiding escape. Vision panels must use fire-rated glazing and intumescent glazing systems covered by the door's test evidence; apertures cut on site without evidence invalidate the door's fire performance.
See also: Ceramic glazing · Georgian wired glass · Intumescent seal