Approved Document B: Fire safety, Volume 1: Dwellings.

Approved Document B is published in two volumes. Volume 1 deals with dwellings: dwellinghouses, flats and their common parts. It sets out one way of meeting requirements B1 to B5 of the Building Regulations 2010 (warning and escape, internal and external fire spread, and access and facilities for the fire service), plus regulation 38 fire safety information. Following it creates a presumption of compliance. You can take another route, such as a fire engineered solution, but you then have to show building control that the functional requirement is met.

The current text is the 2019 edition with the 2020, 2022, 2025 and 2026 amendments. The 2026 changes, in effect from 30 September 2026, add the recommendation for more than one common stair in blocks of flats with a storey 18m or more in height and provisions for evacuation lifts. The published copy also collates the 2029 amendments on fire resistance classes, which take effect on 2 September 2029.

The 2020 amendments added paragraphs 15.13 to 15.16, a direct response to the Grenfell Tower Inquiry. They apply to blocks of flats with a top storey more than 11m above ground level, measured as set out in Diagram D6. The purpose is operational: a firefighter arriving on a landing in smoke, with a torch, needs to know which floor they are on and which way the flats run.

Floor signs read Floor X, using the numbering residents use. The ground floor, the floor nearest mean ground level, is Floor 0 or Ground Floor. Floors above count up from Floor 1. A lower ground floor is Floor -1 or Lower Ground Floor, and floors below count down from Floor -1 or Basement 1. Flat indicator text is sans serif at no less than half the height of the floor sign lettering. In multi-storey flats with two or more entrances, the flat number appears only on the normal access storey.

The signs should be visible from the top step of a firefighting stair and, where possible, from inside a firefighting lift as its doors open. That last point is the one most often missed on drawings: check the sign position against the lift door, not just the stair.

Northern Ireland adopted near identical floor identification and flat indicator wording in Technical Booklet E through its 2025 amendments, at the same 11m trigger. Scotland's domestic handbook has its own storey and dwelling sign guidance for buildings with a storey more than 18m above ground, with different colour and sizing rules. Ireland's TGD B asks for storey identification signs in firefighting stairs and lobbies but has no flat indicator provision of this kind. If you are rolling out one sign family across jurisdictions, design to the strictest combination and check each one separately.