The LWF Blog

Fire Engineering Design and Risk Assessment – Compartmentation – Part 1

August 13, 2018 1:35 pm

In LWF’s blog series for architects and others in the building design business, we talk about fire engineered and prescriptive solutions for use in England and Wales. In part 1 of this series, we discuss compartmentation of buildings for fire safety purposes.


Without effective compartmentation, fire would simply be able to move through a building using the structure as fuel to grow very quickly. Compartmentation is the sub-dividing of a building using fire resisting walls and floors which allows the created rooms or spaces within the build to contain a fire or resist it for a predetermined amount of time.


It’s designed to gain time between a fire starting and it spreading to allow for effective evacuation and for the Fire Service to attend. Compartmentation also means that, when it is completed and maintained properly, it can limit the damage to the property.


For a compartment to work effectively, each enclosing element must be able to resist the spread of fire. The following elements are all necessary:


 All enclosing surfaces such as walls and floors must have an appropriate level of fire resistance


 All the junctions between construction elements must be sealed to maintain fire resistance


 All holes required in walls, ceilings, floors are fire stopped


 Any ducts required through the boundary elements are fire resisting or provided with dampers


 Any openings (doorways or windows) are protected by self-closing fire doors or fire-resisting shutters and/or curtains


 The structure supporting the fire-resistant boundary must be maintained for the duration of the fire-resisting period


Any spaces used to connect compartments, for example – stairways and service shafts – must be protected to restrict fire spread between compartments. These are known as ‘protected shafts’.


Guidance on all elements of fire-resistant walls and floors, fire stopping and the protection of services into the compartment for England and Wales can be found in Approved Document B.


A standard commonly used throughout the world is the NFPA 101 and NFPA 5000.


Fire dampers and fire-resisting shutters are normally operated by fusible link. This means that the fusible link reacts to the heat from a fire and actuates the closure process. While such a process is effective at stopping the spread of fire, smoke can still pass through the opening to other compartment areas. With that in mind, to stop the spread of smoke, smoke detector operated smoke and fire dampers can be used.


In part 2 of this series on compartmentation, LWF will look at how the fire resistance is measured. 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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