The LWF Blog

Fire Engineering Design and Risk Assessment – Fire Alarms in Complex & Tall Buildings – Part 29

December 8, 2016 12:33 pm

In our recent blog series about fire engineering design and fire risk assessment for Architects and others involved in design and build, we have been looking at the use of fire alarms as a part of fire protection. In last week’s blog, we talked about the potential for use on buildings under construction for the purposes of protecting the workforce and the property itself. Today we’re going to continue from that point to look at those places where construction may be ongoing in parts of the building, but other parts may already be operational.


It is reasonably common for a building to be designed and built for mixed use, it could be a shopping complex or a high rise office or residential accommodation. In these cases, it can also be the case that some areas of the complex are occupied by tenants or owners, while some are still undergoing construction.

Fire alarm systems may already be designed and installed in the areas which are in use, but this will not protect the area which is still being built and finished and so a temporary fire alarm system will need to be in use in those areas.


While those systems work on a largely independent basis, they cannot function efficiently if the complexities of a site with both permanent and temporary fire alarm systems is not addressed and certain issues such as evacuation procedures must be agreed upon between the relevant parties.


Additionally, false alarms and their potential impact must be considered. While construction sites can be subject to a high number of false alarms due to the nature of the work and the amount of dust, for instance, the impact of false alarms must be assessed in terms of nuisance and financial considerations for those areas of the building which are already in use by occupiers.


Escape routes from the building must be planned and adhered to in order that sufficient segregation is in place and so that there is sufficient egress from the building for each tenancy.


Equally, access to various areas of the building for the fire service must be considered on a regular basis, which may involve different areas of the site working in cooperation.


Moving on slightly now, to consider tall buildings in particular, it should be borne in mind that while many more tall buildings are in use and under construction, particularly in built-up areas, that a complexity of design of a fire alarm system that must serve as a part of the overall fire protection strategy for the building is very necessary. Different levels of detection must be provided where appropriate, as well as the system being able to give different types of audible warning, depending upon the types of usage within the building.


One such example might be a combination residential and office building, where each apartment within requires smoke detection and alarm sounders, but that there is no need for a general alarm to be given if smoke is detected in one apartment. However, other floors of the same building may contain offices which have a total coverage system.


Careful planning of such systems must be undertaken by an appropriate professional to ensure the overall design of the fire protection provision within the building allows appropriate levels of protection to each area and that the impact of one is addressed when compared against another.


In next week’s blog we will move on from fire alarms to look at Emergency Lighting. 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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