The LWF Blog

Fire Safety for Facilities Management Personnel – Fire Detection & Fire Alarms – Part 198

April 24, 2023 11:19 am

Lawrence Webster Forrest (LWF) is a specialist fire engineering and fire risk management consultancy whose aim is to give information on best practice in fire safety for facilities management personnel through this blog series. In part 197, LWF looked at the wiring of a fire alarm system. In part 198, we will discuss radio-linked fire alarm systems.

Although the majority of fire alarm systems are designed so that the main components of the system are linked by wires, it is possible to have a radio-linked system installed where there is no need for wiring. A radio-linked system is one where the smoke or heat alarms are interlinked through radio frequency signals.

This means that buildings where wiring would be detrimental to the aesthetics of the building (or perhaps a listed building where such wiring would not be allowed) may still be protected by a fire alarm system.

A radio-linked system can also be installed on a temporary basis with the advantage that it is quick to install and easily adaptable. This can be useful when building works are ongoing.

An inherent disadvantage of a radio-linked system is that the trigger points and sounders must be provided with local power. Commonly, this means that they will have a primary and secondary battery and all batteries will need to be charged periodically.

Theoretically, the alarm sounders could be hard wired in the manner of a conventional, wired fire alarm system, but as they are also normally triggered by radio, the power is supplied by internal batteries.

Where a radio-linked system is the right choice for a building, it is essential that a comprehensive radio survey is undertaken to establish the signal strength for the installation and also that no other radio signals are likely to interfere with the communications between parts of the fire alarm system.

If poor signal strength is found in parts of the building due to building construction or the size of the building, radio repeater units can be used to boost the signal strength.

It should be noted that a radio-linked system is not usually affected by the provision of WiFi.

Although wireless fire alarm systems were considered to be unreliable when they first came out in the 1980s, modern incarnations are much more reliable and there is no discernible difference to the user, who can still, for instance, break a manual call point to trigger the alarm.

In part 199 of this series, LWF will consider the types of fire detection and fire alarm system. In the meantime, if you have any queries about your own facilities or wish to discuss this blog series, please contact LWF on freephone 0800 410 1130.

 

Lawrence Webster Forrest is a fire engineering consultancy based in Surrey with over 35 years’ experience, which provides a wide range of consultancy services to professionals involved in the design, development and construction and operation of buildings.

 

While care has been taken to ensure that information contained in LWF’s publications is true and correct at the time of publication, changes in circumstances after the time of publication may impact on the accuracy of this information.