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Last edited 11 Nov 2020

Principal habitable room

The Scottish Building Standards refer to a principal habitable room in relation to the provision of fire detection and fire alarm systems.

They define a principal habitable room as ‘…a frequently used room by the occupants of a dwelling for general daytime living purposes.’

There is a requirement that at least 1 smoke alarm should be installed in a principal habitable room.

However, this requirement can be interpreted in different ways, as it is not clear whether there may be more than one principal habitable room (for example, a kitchen diner and a living room), and so a smoke alarm is required in both rooms, or whether the word ‘principal’ implies there is just one such room.

This issue was clarified in a communication between Fife Council and The Building Standards Division, published by the Scottish Association of Building Standards Managers (SABSM), as Technical Policy Note T04/2012, Detection and Fire Alarm Systems Principal Habitable Room, in 2012.

This made clear that the Building Standards only intend that there should be one principal habitable room. The following guidance was given to help determine which room this should be:

The interpretation of the word 'principal' in this context means the room likely to be the most frequently used and have most occupants using it. In other words risk assess the situation by identifying the living area that is most likely to have a fire (by identifying hazards such as sources of ignition that can give rise to fire) and the most severe consequences (re: potential for injuries and deaths) if there was a fire. In addition, where there is more than one living area; for the purpose of choosing which living area to locate the optical smoke alarm consider each living area's relationship to the route of escape from other rooms in the dwelling (e.g. bedrooms). In other words, consider locating the optical detector in the living area most likely to compromise the route of escape (in fire conditions). The object of the Standard being to ensure an early warning to both the occupants of the living area itself and occupants within other areas of the dwelling.