The LWF Blog

Fire Safety Engineering for Design – Means of Escape Design – Part 102

October 10, 2022 10:47 am

LWF’s Fire Safety Engineering blog series is written for Architects, building designers and others in the construction industry to highlight and promote discussion on all topics around fire engineering. In part 101, LWF discussed the fire protection measures necessary for escape routes, starting with protected lobbies. In part 102, we continue from that point to discuss protected lobbies for stairways in line with NFPA guidance, before considering the safe escape of disabled people from buildings.

NFPA guidance from the National Fire Protection Association in the U.S. is a collection of more than 300 codes and standards which are used throughout the world.

The standards usually require smoke-proof enclosures to be added to stairways in high rise buildings (those which are greater than 23 metres in height) which involves the provision of ventilated lobbies or pressurisation of the stairs. It should be noted that under these provisions, lobbies are not required if the stairways are pressurised.

Where the protection of a lobby is not provided to all escape stairs, it is usual fire safety practice to discount one stair exit from the exit capacity calculations. However, where lobbies are provided, all protected stairways can be included for the means of escape plan, although it is still required to discount one storey exit on the floor of fire origin.

The safe escape of disabled people

The safe escape of disabled people from buildings in a fire situation is based on appropriate fire safety management and means of escape design. The process and design route of evacuation for disabled people must be co-ordinated with the overall access and egress strategy for the building.

Particular provisions relating to the safe evacuation of disabled persons must be made so that they may be promptly evacuated to a place of safety. It is important that this design system does not include rescue by the Fire Service as the time taken to arrive at a fire can vary significantly depending upon demand for services, time of day, distance from the fire station etc. The Fire Service must be regarded as a back-up source of rescue only.

Where it is not possible to provide ‘step-free’ access to a place of safety outside the building, fire protected refuges should be provided. These are normally designed within a protected stair or lobby area, but can also be a separate fire compartment with direct access to a stairway.

In part 103 of LWF’s series on fire engineering, we will continue discuss means of escape for disabled people and the use of refuges. 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 the LWF office on 0800 410 1130.

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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