The LWF Blog

Fire Engineering Design and Risk Assessment – Maintenance of Compartmentation – Part 4

September 6, 2018 10:18 am

In LWF’s Fire Engineering blogs for Architects and others who work in the building design business, we have been looking at compartmentation of buildings to avoid fire spread from the compartment of fire origin to any other area. In part 3 of this series, the fire-resisting performance of elements which go into comprising a fire-resistant compartment was discussed. In part 4, we discuss how a compartment’s integrity is only as good as its ongoing maintenance, before moving on to discuss compartmentation and life safety.


For a compartment to be able to contain a fire for the given amount of time, each element must be maintained to its original standard. Openings may be made in fire-resistant walls, as long as they are protected with the same period of fire resistance as the wall itself. An opening should only be made if it is necessary and so can be permitted for one of the following:


 An appropriately rated fire-resisting door set

 Service pipes, cable trays etc., with appropriate proprietary fire-stopping seals

 Ventilation ducts with fire resisting-dampers etc.


On occasion, fire separating elements have not been properly installed or maintained and this can lead to fire spreading from the compartment of fire origin to other areas of the building, causing further damage and additional danger to the occupants of the building and firefighters.


Some common errors leading to unprotected compartments include:


 Fire stopping was incorrectly installed

 The removal of substrate to allow passage of services, leaving excessive penetrations

 Wear and tear rendering fire compartmentation provision ineffective

 A lack of thought at the time of construction about compartmentation


Life Safety


The benefits to life safety of compartmentation are relatively simple and effective. Compartmentation allow the ‘trapping’ of a fire within the compartment of fire origin for the amount of time the fire-resistance was designed for, usually a minimum of 30 minutes. This amount of time allows building occupants to evacuate the building safely and, if the fire is detected and reported quickly, time for the Fire Service to arrive and attend to the situation. In addition, the limiting of fire spread means the fire will be unable to grow to the extent it would if all the barriers it encountered could be used as a form of fuel, rather than fire-stopping materials. A smaller fire means less danger to building occupants and fire-fighters attending.


Effective compartmentation allows the building owner/occupier to meet certain requirements:


 Meeting travel distances

 Enclosing a special fire hazard

 Supporting a progressive horizontal evacuation strategy (commonly seen in healthcare venues)

 Supporting a phased evacuation strategy (commonly seen in large and tall buildings)

 Support a defend-in-place strategy (commonly used in healthcare and prison buildings)

 Support separate areas having differing occupation types

 Assisting with firefighting operations.


In part 5 of this series on Compartmentation, LWF will look at the National Building Regulations and how fire spreads. 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.


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.


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