Approved Document B 2024 amendments: circular letter

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The Building Regulations 2010 (Amendment) (England) Regulations 2024 New Approved Document B (Fire Safety) to support enhanced fire safety

I am writing to inform you of the amendments made to Approved Document B. The updated guidance published today will come into effect on 30 September 2026.

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The guidance in this Circular Letter applies to buildings and building work in England. This Circular Letter gives an overview of the amendments brought forward and the associated transitional arrangements. Building Control bodies should familiarise themselves with the technical context of the following documents:

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Updated Approved Document B

DLUHC Circular

The Government response to the consultation

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Coming into force date

The amendments to Approved Document B 2019 edition as amended in 2020 and 2022 will be published today, 29 March 2024, and come into force on 30 September 2026.

Description of the changes

The main update of the guidance introduces a new height threshold for the provision of a second staircase in blocks of flats with a storey 18 metres or more in height.

Section 3 of the guidance is also restructured, separating out provisions for horizontal escape and vertical escape adopting a similar structure to Volume 2.

Furthermore, the concept of evacuation shafts is introduced to the guidance to support the provision of evacuation lifts where these are provided.

Finally the proposed amendment introduces new terminology including definitions for evacuation shaft, evacuation lift lobby, interlocked stair and storey exit.

Transitional arrangements

The changes to the guidance take effect on 30 September 2026.

The 2019 edition incorporating the 2020 and 2022 amendments will continue to apply where a building notice or an initial notice has been given to, or a building control approval application with full plans made to, the relevant authority before 30 September 2026 and either the building work to which it relates:

a. has started and is sufficiently progressed before that day; or b. is started and is sufficiently progressed within the period of 18 months beginning on that day.

Note that ‘building notice’, ‘initial notice’ and ‘building control approval application with full plans’ have the meanings given in the Building Regulations 2010.

For the purpose of the amendments highlighted above, building work is to be regarded as ‘sufficiently progressed’:

a. where the building work consists of the construction of a building, when the pouring of concrete for the permanent placement of the trench, pad or raft foundations has started, or the permanent placement of piling has started; or b. where the building work consists of work to an existing building, when that work has started; or c. where the building work consists of a material change of use of a building, when work to effect that change of use has stated.

After that time and from 1 October 2026 all new applications will need to conform to the new guidance.

Enquiries

Telephone enquiries on this Circular Letter should be addressed to the Department for Levelling Up, Housing and Communities on 0303 444 0000 and all email enquiries to buildingassurance@levellingup.gov.uk

Yours faithfully

John Palmer Deputy Director Building Performance Safer Greener Buildings Group Department of Levelling Up, Housing and Communities