The LWF Blog

Fire Engineering Design and Risk Assessment – Fire Alarms & Hazardous Areas – Part 28

December 1, 2016 9:55 am

In this Fire Engineering Design and Risk Assessment blog for architects and others who work in building planning, we have been looking at fire alarms recently. While the majority of fire alarm installations take place in very standard situations, where there is no particular danger from the environment, it is sometimes necessary to position detectors, sounders, wiring and potentially control panels, into areas which might be considered hazardous.


If an area into which parts of a fire alarm are fitted are potentially explosive, they are usually safeguarded in one of the following ways:


Flameproof equipment – The fire alarm equipment is installed within a flameproof enclosure. This ensures that if a fault happens with the equipment and a spark is produced, it is contained within the housing and isn’t exposed to the potentially explosive environment.


Intrinsically safe equipment – The equipment is placed at a point in the potentially hazardous area, where it has been fed through a Zener barrier, which limits the amount of electricity which is allowed into the area. If a fault occurred with the equipment and a spark was produced, it would be insufficient to cause an explosion.


Areas do not need to be potentially explosive to be potentially hazardous. Construction sites, for instance, can be a hazardous environment and one which needs to be protected with a fire warning system so that those people on site can be alerted immediately if a fire starts.


On a very small building site, the fire warning system may be as simple as a management procedure (what a person must do if they find fire to alert others and effect an evacuation). On more complex and larger sites, a correspondingly more involved approach is required in order to ensure fire safety.


The primary issue on a building site should be means of escape – are exit routes clear of obstruction and clearly marked or understood? Do all those persons working on the site know how to safely exit it? A secondary consideration is that of the value of the site itself and how that can best be protected from fire as the build progresses.


When a temporary fire alarm system is installed on such a site, it is important that it is designed to be dynamic and to change as the building does during construction. On some sites, it may even be necessary to review requirements on a daily basis, along with assessment of escape routes and ensuring that information, education and signage reflect the potential for varying nationalities working on site. Regular maintenance of the system must be carried out to ensure that each part can continue to function and has not been contaminated by excessive dust, for instance.


In our next blog, we will look at how fire alarm systems and practices work in buildings with phased or partial occupancy, and also how they differ in very tall buildings. In the meantime, if you have any questions about this blog, or wish to discuss your own project with one of our fire engineers, please contact us.


Lawrence Webster Forrest has been working with their clients for over 25 years to produce innovative and exciting building projects. If you would like further information on how LWF and fire strategies could assist you, please contact Peter Gyere on 020 8668 8663.


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