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Every second counts

Fire Detection and Protection

Interlinked fire detectors in domestic premises can give householders and firefighters more time when fire occurs.

A woman survived when fire spread through her three-storey dwelling in Milton Keynes during the early hours of a July morning. She was alerted by a smoke alarm on the first floor. However, she was prevented from escaping from the dwelling via the stairs, as the fire had already taken hold.

Consequently, she became trapped on the second floor, where her shouts for help were heard by neighbours.

The neighbours erected a ladder to a bedroom window, providing the woman with a means of escape from this life-threatening situation. Their prompt action prevented her from becoming another fire statistic; in the financial year 2010-11 there were 321 fire-related fatalities in England, of which 212 were in dwellings.

Firefighters attended promptly at the scene but on arrival were confronted with a well-developed fire on the ground and first floors, which had already resulted in destruction of the staircase at these levels.

The smoke alarm that alerted the occupant was not interlinked with other smoke alarms in the dwelling. The woman’s narrow escape and the potential risk to firefighters might have been avoided had a fire detection and fire alarm system having interlinked detector/sounder units been installed in accordance with BS 5839-6 (the Code of Practice for fire alarm systems in dwellings). Such systems are provided to give the earliest practicable warning of fire to occupants.

The importance of time

The above incident highlights how important it can be to minimise the time it takes for the alarm to be raised to protect life and property when a fire occurs. Detecting fire and sounding the alarm at the earliest opportunity maximises the time available for occupants to take appropriate escape action and to contact the Fire and Rescue Service.

Fire detection and fire alarm systems

For a typical dwelling, having two or three storeys with no floor exceeding 200 m2 in area, a system consisting of smoke alarms (at least one appropriately-sited smoke alarm on every storey) and heat alarms (in the kitchen and principal habitable room, such as the lounge) will generally meet the recommendations of BS 5839-6, although this must be checked in detail against the requirements of that code of practice. The smoke alarms and heat alarms should generally be interlinked, either by wiring or radio links, to ensure that the earliest warning of fire is provided to the occupants, as a fire detected by any detector element will produce an audible warning by all fire alarm sounders in the dwelling.

BS 5839-6 recommends a smoke alarm no more than 3m outside each bedroom door. In addition, where the designer identifies that the characteristics of the occupants place them at risk when a fire occurs, such as where occupants have deep sleep patterns due to the influence of drugs or have reduced ear sensitivity, alarms may be required within the bedroom to provide an adequate sound level likely to rouse them from sleep.

Compliance with the recommendations of BS 5839-6 is generally necessary in order to meet the applicable requirements of the building regulations in England and Wales, Scotland and Northern Ireland. Guidance on meeting those requirements is given in the associated Approved Documents in England and Wales, Technical Handbooks in Scotland, and Technical booklets in Northern Ireland.


No life was lost in the incident described in this article because vital time to evacuate was provided by the individual alarm that roused the occupant. However, greater time might have been available for evacuation and the fire damage to the property might have been reduced by the installation of a fire detection and fire alarm system having interlinked detector/sounder units in accordance with BS 5839-6.

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