In February 2019, the Ministry of Housing tested a fire door taken from Grenfell Tower. Rated at 30 minutes, it failed after 15 minutes.
The door carried the right label. The problem was the assembly.
That result is why FD30 compliance must be assessed at doorset level, not door level. The rating applies to the complete assembly: leaf, frame, intumescent strips, ironmongery, and smoke seals where required. One non-compliant component fails the whole doorset.
This article covers the full FD30 specification: frame requirements, where Approved Document B and the Fire Safety (England) Regulations 2022 require FD30 doors, the FD30 vs FD30S distinction, responsible person duties, and how to verify an existing installation.
What Are the FD30 Fire Door Specifications?
An FD30 fire door must be a minimum of 44mm thick with a certified fire-resistant core, tested to BS 476 Part 22 or BS EN 1634-1. It requires intumescent strips, a minimum of three fire-rated hinges, a self-closing device, and gap tolerances of 2-4mm between door and frame.
All components must match the certified test evidence for the doorset, the complete tested assembly of leaf, frame, and ironmongery, as distinct from a site-assembled combination of separately sourced components.
A compliant FD30 installation requires all of the following:
- Leaf thickness: 44mm minimum, solid or composite timber core with certified fire-resistant construction
- Test standard: BS 476 Part 22 (British) or BS EN 1634-1 (European); both are accepted under current Building Regulations
- Intumescent strips: heat-activated seals that expand under fire conditions to close the gap between door and frame; must match the door’s certified field of application
- Hinges: minimum three, fire-rated to Grade 13 or as specified in the manufacturer’s test evidence
- Self-closer: must return the door fully to the closed position from any angle; overhead and concealed types are both acceptable if tested with the specific configuration
- Gap tolerances: 2-4mm around the top and sides; bottom gap may vary depending on threshold design and smoke seal configuration
- Glazing: where present, must be fire-rated to the same 30-minute standard, including the glass, beading, and fixing method
The BWF Fire Door Alliance Best Practice Guide is direct on this point: get one component wrong and the assembly has a high chance of failing. A certified leaf hung with incorrect hardware or excessive gaps is not an FD30 fire door.
What Does FD30S Mean?
FD30S means the door provides 30 minutes of fire resistance and is also tested to limit cold smoke leakage. The S suffix indicates the door carries smoke seals in addition to intumescent strips. In most multi-occupied residential buildings, FD30S is the required specification, not plain FD30.
Intumescent strips activate under heat, expanding to close the gap between door and frame once temperatures rise. They do not seal against cold smoke moving through a building before a fire has fully developed. Smoke seals fill that gap. An FD30 door without the S suffix offers no cold smoke protection.
The European equivalent classification is E30Sa.
Where FD30S is the minimum requirement:
- Flat entrance doors onto communal areas in purpose-built flats, confirmed by Approved Document B and the Fire Safety (England) Regulations 2022 guidance
- HMOs of two or more storeys: bedroom, kitchen, and living room doors (LB Ealing HMO Standards, April 2025)
- Escape routes and corridors in commercial buildings where the compartmentation strategy requires smoke control at the door
Plain FD30 is acceptable in some internal locations, but not on escape routes. Wandsworth Borough Council’s guidance states it plainly: “Building Regulations state that a front door to a flat must be FD30S.” If you manage a residential block and the flat entrance doors are FD30 rather than FD30S, they do not meet the required specification.
FD30 Fire Door Frame Regulations: What the Frame Must Meet
The frame is part of the certified doorset and must meet its own specification. Timber FD30 frames require a minimum density of 500 kg/m³, a minimum section of 70 x 30mm, and a rebate of at least 12mm. The gap between the frame and the surrounding wall must not exceed 10mm and must be filled with tested fire-stopping material, not standard expanding foam.
Timber loses integrity under heat at a rate determined by its density. The University of Essex Building Design Guide puts the FD30 minimum at 500 kg/m³ and the FD60 minimum at 650 kg/m³ for hardwood. Use the wrong timber and the frame fails before the leaf does.
Intumescent strips, typically 15 x 4mm, must be fitted exactly as the manufacturer’s test evidence specifies. The position and dimensions are not interchangeable between doorsets.
The wall gap is a separate issue. Any gap exceeding 10mm between frame and structure must be packed with mineral fibre or intumescent mastic. Expanding foam is not acceptable unless it carries its own fire-test evidence.
Reusing an existing frame is one of the most common errors on remediation projects. A certified leaf hung in an unverified old frame is not a compliant installation.
The Fire Door Inspection Scheme recorded that 77% of inspection failures involved excessive gaps between door and frame (FDIS, 2021 dataset, 100,000+ inspections). That gap starts with the frame.
Where Are FD30 Fire Doors Required?
Approved Document B sets out where FD30 and FD30S fire doors are required in England. Requirements vary by building type, height, and the door’s position relative to escape routes. The most common locations are flat entrance doors, HMO bedroom and kitchen doors, stairwells, and escape corridors in commercial buildings.
Building type | Typical requirement |
New build dwellings | FD30S on habitable rooms opening onto escape routes, including loft conversions and integral garages |
Purpose-built flats | FD30S for all flat entrance doors onto communal areas |
HMOs (2+ storeys) | FD30S on bedroom, kitchen, and living room doors |
Commercial buildings | FD30 or FD60 depending on compartmentation strategy; escape corridors typically FD30S |
Requirements for dwellings and flats are set out in Approved Document B Volume 1. Commercial buildings fall under Volume 2. The Fire Safety (England) Regulations 2022 sets out the checking and maintenance duties that apply once doors are installed.
In buildings over 11m, some configurations require FD60 at flat entrance doors rather than FD30S. Where there is no compartment boundary to protect and no escape route to defend, a fire-rated door may not be required. The specific requirement for any building depends on its fire risk assessment and the compartmentation strategy confirmed by building control.
Checking and Maintenance Duties Under the Fire Safety (England) Regulations 2022
The Fire Safety (England) Regulations 2022, in force since 23 January 2023, require responsible persons in multi-occupied residential buildings above 11 metres to check flat entrance doors every 12 months and communal fire doors every three months.
Each check must confirm:
- The door closer functions and returns the door fully to the closed position
- No visible damage to the door leaf or frame
- Intumescent strips and smoke seals are present and intact
- Gaps are within tolerance (2- 4 mm around the top and sides)
- Self-closing devices aren’t propped, wedged, or disabled
Propping a self-closer is illegal and strips the door of its 30-minute protection.
Checks must be recorded, including failed access attempts to flat entrance doors. Guidance on these duties sits in the Fire Safety (England) Regulations 2022 fire door guidance.
Below 11m, the BWF recommends six-monthly checks, rising to monthly or weekly in high-traffic settings like healthcare corridors. The regime carries an estimated cost of £390.8m over ten years, borne mainly by responsible persons in social housing (Explanatory Memorandum, 2022).
How to Verify Whether a Fire Door Is Genuinely FD30 Compliant
A fire door is only verifiably FD30 compliant if it carries a certification label from a recognised third-party scheme and all components match the original test evidence. The label alone is not sufficient: the frame, gaps, hardware, and seals must all conform to the specification the door was certified to.
Check the top edge of the door leaf for a mark from BWF Certifire, BM TRADA Q-Mark, or LPCB. No label means the door cannot be verified.
Even labelled doors can fail. The MHCLG furnace test programme found that two of four Sovereign FD30 doors tested failed the 30-minute standard, as did both Vista Panels FD30 doors tested, despite all being brand-new and correctly labelled (MHCLG, 2018).
For documented assurance, the installation or inspection needs to be carried out by a FIRAS-certified contractor. FIRAS, operated by Warrington Fire and UKAS-accredited, certifies at the individual installer level, not just the company level.
For buildings in South Yorkshire, fire door surveys in Sheffield carried out by FIRAS-certified surveyors provide the compliance evidence that responsible persons need, and the same applies for fire door inspections in Birmingham.
Frequently Asked Questions
What are the legal requirements for a fire door?
Fire doors in England must comply with the Regulatory Reform (Fire Safety) Order 2005 and, where relevant, the Fire Safety (England) Regulations 2022. Approved Document B sets out where fire doors are required and to what standard. Any door on an escape route or between a fire compartment and a communal area must be a tested and certified fire-resisting assembly, rated correctly for its location.
What is the minimum thickness required for an FD30 fire door frame?
There is no single statutory figure for frame thickness, but standard practice for timber FD30 frames is a minimum section of 70 x 30mm with a 12mm-deep rebate and a minimum timber density of 500 kg/m³. The frame must match the certified test evidence for the door being installed. A frame that doesn’t meet this specification invalidates the door’s FD30 rating, regardless of the leaf’s certification.
Do FD30 doors need closers?
Yes, in most applications. A self-closing device is required wherever the door is on an escape route or separates a fire compartment from a communal area. The closer must return the door fully to the closed position from any angle. A functioning closer is one of the first checks under the Fire Safety (England) Regulations 2022 inspection duties.
What are the requirements for a 45-minute fire-rated door?
There is no FD45 classification in the UK fire door rating system. Doors are rated FD30, FD60, FD90, or FD120. A specified 45-minute rating is likely a reference to an FD60 door. Confirm the specification with a fire engineer or building control officer.
Under what circumstances is a fire door not required?
Where there’s no fire compartment boundary to protect and no escape route to defend. In a single-storey building with direct exit to open air, internal doors will often not need to be fire-rated. The specific requirement depends on the building’s fire risk assessment and the compartmentation strategy confirmed by building control.
How can I tell if my door is an FD30 door?
Check the top edge of the door leaf for a certification label from BWF Certifire, BM TRADA Q-Mark, or a similar recognised scheme. The door should be noticeably heavier than a standard internal door, at least 44mm thick, fitted with a minimum of three hinges, and have intumescent strips on the door edge or in the frame rebate. No label means the door cannot be verified as FD30 compliant.
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