MHCLG today published updated copies of Approved Document B (Fire Safety) Vols 1 & 2: 2019 incorporating the 2020 amendment covering sprinklers, wayfinding signage and a correction to the boundaries information.

The amendments do not apply where a building notice or an initial notice has been given to or full plans deposited with a local authority and either the building work to which it relates has started before 26 November 2020 or is started before 29 January 2021.

There are three main changes/additions to AD B Vols 1 & 2:


  • Paragraph 7.4 Vol 1 has been amended to reduce the trigger height for sprinklers in blocks of flats from 30m to 11m.
  • Table B4 Vols 1 & 2 (Minimum periods of fire resistance) has been updated to include a new category height of buildings up to 11m

Wayfinding signage

  • Vol 1 now includes new paragraphs 15.13 to 15.16 providing guidance on signs to assist the fire service identify each floor and flat  in a block of flats 11m or more in height
  • The new signage will be found:
    • On the landings of every protected stairway
    • In every protected lobby or corridor into which a firefighting lift opens
    • Guidance id provided on the minimum letter height, wording, style and positioning/legibility  of the signs.


  • A correction to an error which appeared in the 2019 edition of AD B
  • Vol 1 (paragraph 11.5) and Vol 2 (paragraph 13.5) have been amended to include purpose group,2 (Residential – Institutional/Other) for application of a ‘notional boundary’ between two buildings on the same site.

To view these updated documents please click here