The LWF Blog
Fire Safety for Healthcare Premises – Cavity Barriers and Sprinklers – Part 43October 11, 2018 10:45 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 42 of this series, we looked at how cavity barriers should be installed in uninterrupted concealed spaces or cavities and also some exceptions to the rules. In part 43, we will continue looking at the use of cavity barriers in healthcare buildings.
There are some instances where cavity barriers should not be installed. For instance, in cavity walls, in double-skinned insulated roof sheeting or below a floor next to the ground or oversite concrete (providing the cavity is less than 1000 mm in height or is not accessible by persons and there are no openings in the floor where it would be possible for combustibles to accumulate).
It should be noted that combustible materials are not permitted to be placed within or exposed to the cavity, with certain exceptions:
– Timber lintels, window or door frames, or the ends of timber joists
– Pipes, conduits or cables
– DPC, flashing cavity closer or wall tie
– Thermal insulating materials (two leaves of brick block or concrete each at least 75 mm thick, 100 mm maximum cavity width.
While openings in barriers should be avoided, there are some exceptions, such as doors which have 30-minutes fire-resistance, pipes, cables, conduits, openings fitted with a suitably mounted automatic fire and smoke damper or ducts (which, unless they are fire-resisting and fitted with a suitably mounted automatic fire damper where they pass through the cavity barrier).
Other situations where cavity barriers should not be used might include those not based on structural limitations. One example is that of an operating department where the complex ventilation ductwork systems mean that cavity barriers would seriously compromise service access and therefore, safe access and egress for maintenance staff.
Operating departments are restricted access and very well supervised once in use, along with all hazard areas being enclosed in fire-resistant construction. The risks due to not having a cavity barrier are therefore lower than in other areas of a healthcare building.
In part 44 of this series, LWF will introduce the subject of sprinkler systems in healthcare buildings and look at how the design team might approach their use or justify the lack thereof. 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.