Domestic Electricians

The installation of smoke alarms, or automatic fire detection and alarm systems can significantly increase the level of safety by automatically giving an early warning of fire.

Part B (Fire Safety 2006 edition) of The Building Regulations 2000 advises that all new dwellings (including those converted into dwellings and dwellings when altered or extended) should be fitted with an automatic fire detection and alarm system.

Self-contained and interlinked smoke alarms are suitable for most dwelling houses

Type of smoke alarm

The self-contained smoke alarm should be mains operated (preferably with a secondary power supply) and designed to conform to BS5446 Part 1.

Where more than one alarm is provided they should be interconnected, so that detection by one unit operates the alarm signal in all of them.

Number and position of smoke alarms

The smoke alarms should be provided to the circulation area of each and every floor of the dwelling. The unit should be no more than 7.5m from the door to every habitable room, whilst also being close enough to bedroom doors for the alarm to be effective when occupants are asleep (say 3m).

Note: If the kitchen is not separated from the circulation space by a door, a compatible interlinked heat detector should also be provided in the kitchen.

Each alarm should preferably be fixed to the ceiling in a central position and at least 300mm from any wall or light fitting. If the unit is designed to be wall mounted, it should be fixed above the level of the doorway opening in accordance with manufacturer’s instructions.

Alarms should not be fixed next to or directly above heaters, ducted air outlets or in bathrooms, showers, cooking areas or garages, where steam, condensation or fumes can give false alarms. Likewise, alarms should not be fitted in very hot or very cold rooms (e.g. boiler rooms or unheated porches), where the air currents may move smoke away from the unit.

When positioning a self-contained smoke alarm consideration should be given to the safe testing, cleaning and maintenance of the unit. For this reason the alarm should not be fixed over a stair shaft or an opening in a floor.

Installation & Maintenance

All electrical works are required to meet the requirements of Part P (Electrical Safety) and must be designed, installed, inspected and tested by a person competent to do so.

Prior to completion building control should be satisfied that Part P has been complied with.

The unit should be permanently wired to a separate fused circuit at the distribution board, via mains transformer if they operate on a low voltage supply or fixed in accordance with BS5446 Part 1. No other electrical equipment should be connected to this circuit (apart from a dedicated monitoring device installed to indicate power failure) unless the system has a stand-by power supply which can operate during mains power failure. It can therefore be connected to a regularly used local lighting circuit. All should conform to the IEE Wiring regulations. The alarm should preferably not be protected by any residual current device (RCD).

The manufacturers instructions containing the operating, testing and maintenance of the unit should always be retained by the occupier of the dwelling.