Fire door specification guide

At a glance

England only. Read from Approved Document B (2019 edition incorporating the 2020, 2022, 2025 and 2026 amendments) on 5 November 2026.

What a fire door is, and how to read its label

A fire door is not a door that is thick or heavy. It is a doorset: leaf, frame, seals, hinges, closer, lock and glazing that were tested together, are certified together and are fitted as the installation instructions say. Approved Document B asks for a minimum fire resistance, in minutes, for each position, and says the test evidence must apply to the complete installed assembly, because small differences in detail may significantly affect the rating (paragraph C4).

Two notations. FD30 is the older British form: thirty minutes of integrity when tested to BS 476-22, with an S added where restricted smoke leakage at ambient temperature is needed (C1(a)). The European form is E30 Sa: E for integrity, thirty minutes, Sa for smoke leakage at ambient temperature, tested to BS EN 1634-1 (fire) and BS EN 1634-3 (smoke) and classified to BS EN 13501-2 (C1(b)). Table C1 prints both side by side and notes that national classifications do not necessarily equate with European ones, so a product cannot normally assume a European class unless it was tested for it. The Approved Document asks for integrity (E) only; it does not ask for insulation (C2), and it observes that fire doorsets often give no significant insulation (C8).

What S and Sa ask for. Table C1 note 2: unless the doors are protected by pressurisation to BS EN 12101-6, an S or Sa door should either have a leakage rate not over 3 m³ per metre per hour (from the head and jambs only) when tested at 25 Pa under BS 476-31.1, or meet the Sa classification when tested to BS EN 1634-3.

FD20 or FD30. The Approved Document asks for 20 minutes in some places and 30 in others. The BWF Fire Door Alliance takes the view that an FD30 door with intumescent seals should be specified as the minimum even where 20 minutes is required, and says its scheme members no longer test and sell an FD20 door without seals (Fact Card 9, September 2024). That is a trade body’s position, not a requirement of the Approved Document.

Standards behind the notation. Each line records what we saw, not what the standard says.

Where each rating applies: Table C1

Table C1 of Approved Document B sets the minimum rating by position. The table is the same in Volume 1 (dwellings) and Volume 2 (buildings other than dwellings). The rows below are condensed; the paragraph numbers are the table’s item numbers. The fire strategy for the project can ask for more than the table, and the fire engineer or building control body decides which row applies to a given door.

Around the table, Appendix C also says:

• Self-closing (C5, C6). All fire doorsets, including flat entrances, should have a self-closing device, except fire doorsets to cupboards, to service ducts normally locked shut, and within flats and dwellinghouses. Where self-closing would interfere with use, a door may be held open by a fusible link (not on a means of escape unless C7 is met), by an automatic release linked to the fire detection and alarm system, or by a door closer delay device.
• Hinges (C10). Unless shown to be satisfactory when tested as part of the doorset, the essential components of a hinge on a fire door should be made entirely from materials with a melting point of at least 800°C.
• Signs (C11, C12). Fire doorsets should carry a sign to BS 5499-5 (‘Fire door keep shut’, ‘Fire door keep locked shut’ or ‘Automatic fire door keep clear’) on both sides, except doors to and within flats and dwellinghouses, bedroom doors in ‘residential (other)’ premises and lift doors.
• Openings (C8). Unless a door gives both integrity and insulation as the wall requires, no more than 25 per cent of the length of a compartment wall should consist of door openings.
• Guidance named (C14, C15). BS 8214 for non-metallic leaves, a TRADA publication for timber doorsets, a DSMA code of practice for metal doors, and ‘Hardware for Fire and Escape Doors’ from the Door and Hardware Federation and the Guild of Architectural Ironmongers, because hardware can significantly affect performance in a fire.

From 2 September 2029. The 2029 amendments to Approved Document B replace Appendix C: the Table C1 column for BS 476-22 goes, the table gives the European classification only (for example ‘30 minutes Sa’), and doorsets may be classified to BS EN 13501-2 or have their performance assessed as capable of meeting a classification under paragraphs B1 to B5. The 2022 to 2026 text continues to apply to work that has already started or been notified, on the transitional terms in the booklet.

The evidence: what makes a doorset a fire door

What makes a door a fire door is paper as well as timber. The documents below are the chain from the test to the door on site. Ask for them for the exact doorset on the schedule, before manufacture, not after.

Gaps are certified, not designed. The permitted gap between leaf and frame is set in the leaf’s field of application, and the installation instructions repeat it (BWF Fact Cards 10 and 11). The figures that circulate are not design figures. BWF Fact Card 11 gives, as a general guide, 2 to 4 mm along the sides and head and, for the bottom, usually 8 to 10 mm, or 3 mm where smoke control is also needed, and says to check the manufacturer’s instructions and the data sheet. The government’s fire door guidance for blocks of flats (revised August 2025) calls 4 mm the industry standard for the most a gap should be, other than at the bottom, as a visual check on a door already in service. Neither is a figure to write on a drawing: the certificate for your doorset governs.

Things that void a certificate. The BWF cards are direct about four: planing or cutting the leaf or frame to suit the opening; fitting a new leaf into an old frame without checking the frame against the leaf’s data sheet (Fact Card 11); glazing on site, where its certified doors must come from the maker already glazed (Fact Card 10); and swapping in hardware or seals that the certificate does not list.

When the design is not a standard doorset. A veneered face, an oversize leaf, special glazing or unusual ironmongery may sit outside what a certificate covers. Our reading of Appendix C and the BWF cards is the ladder below: the further a door departs from its certificate, the more evidence it needs. Who may give the written confirmation or carry out the assessment is a question for the certification body and a fire door specialist, and is not answered by any document we read.

What changed from 2022 to 2029

Several things changed between 2022 and 2026. Only the first two are law for owners of blocks of flats; the others are guidance and standards that a specifier will meet.

What regulation 10 asks. It applies to a building with two or more sets of domestic premises and common parts through which residents would need to evacuate, in England. The responsible person must tell residents that fire doors should be kept shut, that they must not tamper with self-closing devices and that faults are to be reported, when a resident moves in and then within each twelve months (10(1) to (3)). In such a building above 11 metres, the responsible person must use best endeavours to check flat entrance fire doors at least every 12 months, keep a record of the steps taken, and check fire doors in communal areas at least every 3 months, including that the self-closing devices work (10(4) to (7)).

What it does not ask. The August 2025 revision says plainly that the Regulations are not meant to make existing flat entrance doors meet the current standards for new doors, that the checks are simple and visual, and that they assume the door’s design and installation were already adequate. For a designer the practical point is the record: a door register that says what each door is, where it is and what certificate it carries is what any later check starts from.

Not covered here. Hotels, offices and other buildings with no domestic premises are outside regulation 10 and fall under the Fire Safety Order’s general duties; Wales, Scotland and Northern Ireland have their own documents. Take both to the project’s fire engineer.

Who supplies the door, and what the schedule should say

What the studio does and does not say. The studio coordinates manufacture of bespoke joinery through partner workshops. It does not certify fire doors, and this sheet does not claim that the studio or its partner workshops supply certified fire doorsets. Where a project needs fire doors, the question for any supplier is which certified doorset, from which certified maker, and the certificate is the answer. If a bespoke finish or detail is wanted on a fire door, raise it at tender with the door maker.

On the door schedule, for each fire door:

• The position and the rating from the fire strategy (for example [E30 Sa] or [FD30S]), with the Table C1 item it comes from.
• That it is supplied as a complete certified doorset, and the certificate reference once chosen.
• Finish, size, glazing, vision panel and ironmongery, each marked as inside or outside the certificate.
• Self-closing device, hold-open method (if any) and the sign required.
• That no leaf or lining is planed, scribed or cut on site, and who fits the door.
• What goes in the handover record: certificate, field of application, installation instructions, as-fitted gaps and the date.

The leaf is also an access door: the clear width the regulations measure is not the leaf width, and a certified leaf has its own size limits. The door sizes and tolerances sheet covers the access figures; the fire documentation matrix lists what to ask for across the whole schedule.

Fire doorsets to [positions on fire strategy drawing, ref [ ]] to achieve [E30 Sa / E30 / E20 Sa] ([FD30S / FD30 / FD20S]) as Approved Document B Table C1 item [2(a)] and the project fire strategy, tested to BS EN 1634-1 [and BS EN 1634-3 where Sa is required] and classified to BS EN 13501-2, and supplied as a complete doorset (leaf, frame, seals, hinges, closer, lock, latch and glazing as tested) with third-party certification. Hinges as tested. Certificate, field of application and installation instructions to be submitted before manufacture.

Any veneer, lacquer, size, glazing or ironmongery not covered by the doorset certificate to be identified at tender, with the certificate holder's written confirmation or an assessment report [reference]. No leaf or lining to be planed, scribed or cut on site; no existing frame reused unless checked against the leaf's data sheet.

Self-closing devices to all fire doorsets except [cupboards, ducts normally locked shut, doors within flats]. Signs to BS 5499-5 on both sides unless exempt (ADB C12). Labels or plugs not to be removed or painted over.

Door schedule for the O&M manual: position, rating, certificate reference, installer, date fitted and as-fitted gaps for every fire doorset, in the form [ ].

Standards and sources

• Approved Document B volumes 1 and 2, 2019 edition with the 2020, 2022, 2025 and 2026 amendments, and the 2029 amendments (England): Appendix C, Table C1, Section 17. Read 5 Nov 2026.
• The Fire Safety (England) Regulations 2022, SI 2022/547: regulations 1, 3 and 10; in force 23 January 2023.
• Fire Safety Act 2021, section 1: in force for England 16 May 2022.
• gov.uk fire door guidance under the 2022 Regulations: revised 8 August 2025.
• BWF Fire Door Alliance Fact Cards 9, 10 and 11 (September 2024): trade body guidance.
• BS 8214:2026; BS EN 1634-1; BS EN 13501-2:2023; BS 476-22: status only; not read. Confirm the current edition.

Questions we are asked

What is the difference between FD30 and FD30S?

Both are 30 minutes of integrity when tested to BS 476-22. The S means the doorset also limits smoke leakage at ambient temperature. Approved Document B Table C1 asks for the S version at, for example, a flat entrance off a shared space and the enclosure of a protected stairway, and the plain FD30 for a door in a cavity barrier. The European forms are E30 Sa and E30.

Should I write FD30S or E30 Sa?

Table C1 currently prints both, and says national classifications do not necessarily equate with European ones, so a door tested to one cannot normally assume the other. From 2 September 2029 the guidance gives the European classification only. Name the classification the doorset certificate carries, and the position it serves.

Can a bespoke veneered or oversize door be a fire door?

Only if the test evidence, or an assessment, covers that exact build. Approved Document B paragraph C4 says the evidence must apply to the complete installed assembly, because small differences in detail may significantly affect the rating. Ask the door maker and the certification body whether the veneer, size, glazing and ironmongery are inside the certificate. This sheet does not claim that the studio or its partner workshops supply certified fire doors.

What did the 2022 changes mean for fire doors?

The Fire Safety Act 2021 brought the doors between flats and common parts within the Fire Safety Order in England from 16 May 2022. The Fire Safety (England) Regulations 2022, in force from 23 January 2023, added duties under regulation 10: tell residents about fire doors, and in blocks over 11 m check flat entrance doors yearly and shared fire doors quarterly. The government revised its guidance in August 2025 to say the checks do not require existing doors to meet current new-door standards.

What gap should a fire door have?

The gap on the certificate. It is set in the leaf's field of application and repeated in the installation instructions. BWF gives general figures of 2 to 4 mm at the sides and head and usually 8 to 10 mm at the bottom, and government guidance uses 4 mm as the most a gap should be when checking a door in service, but none of these is a design figure.

Who is responsible for checking fire doors in a block of flats?

The responsible person for the building, under regulation 10 of the Fire Safety (England) Regulations 2022, where the building has two or more sets of domestic premises. The checks are simple and visual, and need not be done by a specialist, but repair or replacement of a fire door must be done by a competent contractor.