BS 9991 Changes to be aware of

British Standard 9991:2015 Fire safety in the design, management, and use of residential buildings was developed to complement BS 9999: Code of practice for fire safety in buildings’ design, management, and use.

The standard ensures adequate fire safety measures within residential buildings by giving recommendations on the design, management and use of smoke ventilation systems and is considered an acceptable approach to the guidance given in Approved Document B.

The guidance covers Dwellings (single-family dwelling houses, self-contained flats or maisonettes), residential accommodation that provide kitchen facilities with individual bedrooms (such as student housing), and specialised housing. BS 9991:2015 covers a variety of fire safety installations, including fire detection, alarm systems and fixed fire-fighting systems.

BS 9991 is expected to undertake some significant changes; a draft of what these changes could include has already been released (BS 9991:2021). Here are some of the changes that are likely to be implemented in the new version:

  • We expect a defined distance added to the hob clear space for open plan construction and escape routes. The draft standard defines this as between 1.8 meters from the hob with a further 0.9m escape route to allow for wheelchair access.
  • Further clarification on split stairs within a tall, single stair building.
  • The draft standard includes the recommendation for premises information boxes in blocks over 11m and signage to help find escape routes. This is adopted from ADB.
  • The inclusion of an evacuation alert system in blocks over 18m in line with BS 8629.
  • The standard references the latest BS9251 standard on residential sprinklers, including the provision of sprinklers in sterile areas and corridors.
  • The inclusion of evacuation lifts in all residential buildings served by a residential lift.
  • The inclusion of a dedicated lift lobby between the stair and the residential corridor.

The following change will likely need further discussion on the panels following the review; however, they are worth noting:

  • Residential buildings over 18m should be provided with two stairs with mechanical ventilation or a single stair where the stair, lift and lift lobby will be protected with a pressurisation system and the corridor served by a separate smoke ventilation (natural or mechanical) systems.

Note; if mechanical, the make-up/replacement air cannot be provided through the head of stair and lift lobby.

There are some other technical changes related to the maintenance of equipment, however, the points listed above are some that we’ve recognised as crucial design changes.

Whilst the aforementioned changes have not yet been actioned, we feel it is worth keeping them in mind for future projects. 


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