The LWF Blog

Fire Safety for Healthcare Premises – High Risk Fire Hazards & Precautions – Part 89

August 19, 2019 1:25 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 88, LWF continued looking at the provisions which must be made for fire safe operation of main kitchens in healthcare buildings. In part 89, we will look at the fire safety implications of ventilated ceilings in main kitchens, which are intended to permit the passage of air from the kitchen to the void above, before extraction to open air.

Due to the nature of the activities undertaken in kitchens generally, the air which passes into the void above the ventilated ceiling is not clean air. Airborne grease and other gaseous by-products are also extracted and for this reason, some suspended ceilings include metal cassettes intended to trap the grease and detritus. A fire hazard can be created in such situations by greasy dirt accumulating in the ceiling space along with potentially, other pipework which is routed above the ventilated ceiling. The regular cleaning of the cassettes and area generally is not a simple or quick task and so is often forgotten with the adage ‘out of sight, out of mind’ seeming to apply.

With the potential for a serious fire in the space above a ventilated ceiling, the use of them should only be considered where the following can be achieved:

– The area of a single unit of ventilated ceiling should not be greater than approx. 60 metres.
– The free area of ventilation into the void should be not less than 25% of the area of the suspended ceiling evenly distributed over the entire area.
– Each ceiling unit should be totally segregated from the next with the use of non-combustible imperforate downstands which extend from structural soffit to suspended ceiling. The perimeter of any such units or series of units should be segregated by cavity barriers from any other conventional ceiling void by using imperforate fire-resisting construction and should be fire-stopped.
– All cassettes should be easily removable for frequent cleaning and each void should be accessible for inspection and cleaning.

It should go without saying that efficient management practices should be implemented and checks should be undertaken to ensure that the regular cleaning and inspections indicated are carried out as appropriate.

In part 90, LWF will look at the potential for corrosion in ductwork and what fire-fighting controls should be in place for use in a fire situation. 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 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.