The LWF Blog

Facilities Management – Fire Detection & Fire Alarm Systems – Alarm Devices – Part 13

September 1, 2016 11:56 am

In our recent fire safety blog series for those working in Facilities Management, we have been exploring the types of fire detection and fire alarm systems and their major component parts. In today’s blog we will continue from where we left off in part 12, looking at the different types of alarm system, their components and their suitability for use.

 

In large assembly areas where a high concentration of the occupants will be members of the public, a traditional fire alarm sounder could cause issues with panic, unfamiliarity with the environment and disorientation. In this kind of situation, it can be useful to install a Voice Alarm System which, instead of sounding bells or electronic sounders, emits a human voice as part of an appropriately designed public address system.

 

Research has shown that while there is often a delay before evacuation actions begin to be taken in cases where simple alarm sounders are used – because people are unsure what to do, a voice sounder giving simple instructions reduces this indecision and therefore, the delay.

 

When considering the upkeep and maintenance of any fire alarm system, wiring is of the utmost importance. The control equipment should monitor the wiring to sounders, detectors and call points and if a problem is detected, an error code is given (fault). While this system is very useful, it remains necessary to ensure that the cable type installed and its protection is not liable to mechanical damage.

 

Indeed, all fire alarm circuits and the mains power supply which powers the control and indicating equipment must consist of fire-resistant cables, so that there is no failure in cases where a fire could cause damage to the cables.

There are different types of fire-resistant cables suitable for use.

 

BS 5839-1:2013 Fire detection and fire alarm systems for buildings. Code of practice for design, installation, commissioning and maintenance of systems in non-domestic premises, provides information on the levels of performance of fire-resisting cables, namely ‘standard fire resistance’ and ‘enhanced fire resistance’.

 

The standard recommends that those cables classified as ‘enhanced fire resistance’ need only be used on those buildings where sprinkler protection is not provided and which are more than 30m in height, with 4 or more evacuation phases or where remote areas from the fire may not need evacuating at all, such as hospital complexes.

 

The standard does, however, accept that certain fire engineered solutions may call for the use of ‘enhanced fire resistance’ cables.

 

In next week’s blog we will continue on this subject, looking first at Radio-linked Systems. In the meantime, if you have any queries about your own facilities or wish to discuss this blog series, please contact Peter Gyere in the first instance on 0208 668 8663.

 

Lawrence Webster Forrest is a fire engineering consultancy based in Surrey with over 25 years’ experience, which provides a wide range of consultancy services to professionals involved in the design, development and construction and operation of buildings.