Fire Safety in New Build Flats: A Developer's Guide

Developing new build flats in England and Wales requires careful attention to fire safety at every stage, from initial design through to handover and beyond. The regulatory landscape has tightened significantly since 2020, with the Building Safety Act 2022, updated Approved Document B, and the new regime for higher-risk buildings all raising the standard that developers must meet. Fire doors are central to the fire strategy of any residential block, and getting them wrong can delay completion, trigger enforcement action, and expose the developer to long-term liability.

Building Regulations and Approved Document B

Approved Document B (ADB) of the Building Regulations is the primary guidance document for fire safety in new buildings. It sets out the requirements for means of escape, fire spread, access for the fire service, and — critically for this discussion — compartmentation. In blocks of flats, each flat is treated as a separate fire compartment, meaning the walls, floors, ceiling, and doors that enclose each flat must resist fire for a specified period, preventing spread from one flat to another or into the communal areas.

For buildings up to 11 metres in height, flat entrance doors must achieve FD30S rating (30 minutes of fire resistance with smoke seals). For buildings over 11 metres, the requirements increase — doors to protected stairways typically require FD60 rating, and the overall fire strategy becomes more complex. Doors within individual flats (bedroom doors, kitchen doors) do not generally require a fire rating in new builds, though some developers specify FD30 doors throughout as a belt-and-braces approach that simplifies procurement and future management.

Compartmentation and the Role of Fire Doors

Compartmentation is the principle of dividing a building into discrete zones that contain fire and prevent it spreading beyond the zone of origin. In a block of flats, each flat is a compartment, the stairway is a compartment, and corridors may form part of the protected means of escape. Fire doors are the moving elements within this compartmentation — they must close reliably to maintain the integrity of the compartment when a fire occurs.

Every fire door in the communal areas of a new build flat development must be a complete, tested, certified assembly. This means the door leaf, frame, intumescent strips, smoke seals, hinges, closer, lock or latch, and any glazing must all be covered by the manufacturer's fire test evidence. Building control inspectors will check for certification labels, correct gap tolerances, and proper installation during their site inspections. Increasingly, they are also asking for documentary evidence of the full product chain — from manufacturer to site — as part of the golden thread requirements.

Specification Tips for Developers

Standardise the fire door specification across the development wherever possible. Using one manufacturer for all fire doors simplifies procurement, reduces the risk of incompatible components, and makes it easier to maintain the golden thread documentation. Specify doors with pre-hung frames and factory-fitted seals where possible — this reduces the scope for installation error on site.

Consider access requirements: flat entrance doors in new builds must comply with Approved Document M (access) as well as Approved Document B (fire). This typically means a minimum clear opening width of 775mm, a level threshold, and lever handles operable with one hand. These requirements can be accommodated within the fire door specification but must be considered from the outset.

Finally, plan for the handover. The Building Safety Act requires developers of higher-risk buildings to produce a detailed building safety case, including comprehensive information about every fire door installed. Even for buildings below the higher-risk threshold, providing the management company or freeholder with a complete fire door schedule — listing every door's location, specification, certification reference, and installation date — is good practice and increasingly expected by warranty providers and building insurers.