Installations based on smoke alarms
1.11 Smoke alarms should normally be positioned in the circulation spaces between sleeping spaces and places where fires are most likely to start (eg
kitchens and living rooms) to pick up smoke in the early stages, while also being close enough to bedroom doors for the alarm to be effective when
occupants are asleep.

1.12 In a house (including bungalows) there should be at least one smoke alarm on every storey.

1.13 Where more than one smoke alarm is installed they should be linked so that the detection of smoke by one unit operates the alarm signal in all of them. The manufacturers’ instructions about the maximum number of units that can be linked
should be observed.

1.14 Smoke alarms should be sited so that:
a. there is a smoke alarm in the circulation space within 7.5m of the door to every
habitable room;

b. where the kitchen area is not separated from the stairway or circulation space by a door, there should be a compatible interlinked heat detector in the kitchen, in addition to whatever smoke alarms are needed in the circulation space(s);

c. they are ceiling mounted and at least 300mm from walls and light fittings (unless in the case of light fittings there is test evidence to prove that the proximity of the light fitting will not adversely affect the efficiency of the detector). Units designed for wall mounting may also be used provided that the units are above
the level of doorways opening into the space, and they are fixed in accordance with manufacturers’ instructions; and

d. the sensor in ceiling mounted devices is between 25mm and 600mm below the ceiling (25-150mm in the case of heat detectors).

Note: This guidance applies to ceilings that are predominantly flat and horizontal.

1.15 It should be possible to reach the smoke alarms to carry out routine maintenance, such as testing and cleaning, easily and safely. For this reason smoke alarms should not be fixed over a stair shaft or any other opening between floors.

Smoke alarms should not be fixed next to or directly above heaters or air conditioning outlets. They should not be fixed in bathrooms, showers, cooking areas or garages, or any other place where steam, condensation or fumes could give false alarms.

Smoke alarms should not be fitted in places that get very hot (such as a boiler room), or very cold (such as an unheated porch). They should not be fixed to surfaces which are normally much warmer or colder than the rest of the space, because the temperature difference might create air currents which move smoke away from the unit.

A requirement for maintenance can not be made as a condition of passing plans by the Building Control Body. However the attention of developers and builders is drawn to the importance of providing the occupants with information on the use of the equipment, and on its maintenance (or guidance on suitable maintenance contractors).

Note: BS 5839: Part 1 and Part 6 recommend that occupiers should receive the manufacturers’ instructions concerning the operation and maintenance of the alarm system.