Last edited 28 Jun 2016

Inner room definition

Approved document B, Fire Safety, Volume 1 Dwelling houses, defines an 'inner room' as:

‘…a room whose only escape route is through another room.’

It suggests that an inner room is at risk if a fire starts in the other room (the access room - that is, ‘a room through which the only escape route from an inner room passes’).

This situation may arise with open-plan layouts and galleries.

Such an arrangement is only acceptable where the inner room is:

  • A kitchen.
  • A laundry or utility room.
  • A dressing room.
  • A bathroom, WC, or shower room.
  • Any other room on a floor, not more than 4.5m above ground level, provided with an emergency egress window (which complies with paragraph 2.8).
  • A gallery (which complies with paragraph 2.12).

A room accessed only via an inner room (an inner-inner room) may be acceptable if it complies with the above, not more than one door separates the room from an interlinked smoke alarm and none of the access rooms is a kitchen.

[edit] Find out more

[edit] Related articles on Designing Buildings Wiki