The LWF Blog

Fire Engineering for Healthcare Premises – Evacuation Time – Part 28

March 29, 2021 1:01 pm

In LWF’s blog series for healthcare professionals, our aim is to give information on best practice of fire safety in hospitals and other healthcare premises. In part 27 of Fire Engineering for Healthcare Premises, LWF looked at the effects of smoke on movement and tenability limits. In part 28, we will discuss exit choice and egress modelling.

In order for an orderly fire evacuation within a healthcare building, it is important that staff have a good knowledge of the layout of their department. While staff play a vital role in organising the evacuation, there will be building occupants – perhaps day patients or visitors – who will make their own way and may not have the area knowledge of the building to choose the nearest exit.

People inside the building will simply attempt to exit using the most convenient or known route and will not choose an exit based on their width (indeed they would be unable to do this if they had no knowledge of the building) and this means the number of people using each exit will not be optimised in order to minimise the total evacuation time, as it might be in a predictive simulation.

A sensitivity analysis should be performed where it is hard to quantify the probability of choosing any given exit. This means that the uncertain variables can be taken into account when planning.

The popular perception of people panicking when a fire alarm is sounded is largely false. There is no actual evidence that experiencing panic will make building occupants either evacuate more quickly or refuse to evacuate because they are panicking. It is important that this is included in staff training to ensure panic is not deliberately invoked with the aim of making people move more quickly.

Special fire safety precautions will be required when handling the needs of dependent and very high dependency patients and patients with disabilities.

When undertaking egress modelling for a healthcare building, it can be difficult to simulate human behaviour, yet it must be addressed in order to obtain accurate results. Because not all aspects of human behaviour in a fire situation are fully understood, or can be easily quantified, it is important that sensitivity analyses are undertaken. It should be noted that validation of the behavioural aspects of existing models is currently rather poor.

In Part 29 of LWF’s blog series, LWF will begin to look at Risk Assessment. 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 LWF on freephone 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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