The LWF Blog
Fire Safety for Healthcare Premises – Internal Fire Spread through Structure – Part 33July 31, 2018 11:03 am
In LWF’s blog series for healthcare professionals, the aim is to give information on best practice of fire safety in hospitals and other healthcare premises. In part 32 of this series, we began to look at the potential for internal fire spread through the structure, including how the load-bearing elements of a building are required to have a minimum period of fire resistance to prevent collapse. In part 33, LWF continues to look at structural elements in terms of fire resistance.
While structural elements such as columns, beams, load-bearing walls and floors must be fire-resistant for a minimum period to avoid the potential for load-bearing failure, it may not be necessary for roof structures and those elements which support only the roof.
A roof may not require fire-resistance for life safety purposes unless it meets one of the following criteria:
– The building stability depends upon the roof
– The roof itself also serves as a floor, as would be the case with a rooftop car park or plantroom
– The roof is used as an escape route
The minimum period of fire-resistance for a given element should be as follows:
Single-storey healthcare buildings must have 30 minutes minimum fire resistance whether or not sprinklers are in place.
Healthcare buildings up to 12m above ground or with basements up to 10m deep should have 60 minutes fire-resistance, reduced to 30 minutes fire-resistance where sprinklers are in place, except in the case of basements.
Healthcare buildings with storeys over 12m above ground or with basements more than 10m deep should have 90 minutes fire-resistance un-sprinklered and 60 minutes sprinklered.
Healthcare buildings with storeys over 30m in height are not permitted to be un-sprinklered and have a minimum fire resistance of 90 minutes when sprinklered.
Where references to sprinklered buildings are made, this must be read as a reference to a life safety sprinkler system suitable for purpose, installed and maintained as per BS EN 12845. (https://shop.bsigroup.com/ProductDetail/?pid=000000000030337104) In addition, it should be noted that in order to reduce the fire-resistance minimum duration of elements of a structure, the entire building must be sprinkler protected. Partial sprinkler coverage cannot provide the same level of protection for structural elements.
While partial sprinkler coverage cannot provide a reason to reduce the minimum fire-resistance of structural elements of the building, it may still be a useful provision for the fire safety design, as it can help to mitigate localised fire risks and offer other fire design benefits. A fire design should be undertaken by a Fire Engineer to provide a solution based on fire-engineering evidence.
In part 34, LWF will discuss compartmentation in healthcare venues. 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.