The LWF Blog

Fire Safety for Healthcare Premises – High Risk Fire Hazards & Precautions – Part 88

August 12, 2019 12:54 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 87, LWF began to look at certain high fire hazard areas within healthcare premises, starting with the main kitchens. In part 88, we continue looking at the provisions which must be made for fire safe operation of main kitchens in healthcare buildings.

Main Kitchens Ductwork & Fire Safety

Kitchen equipment which uses oils or fats should have short extract ductwork which discharges into the external atmosphere directly above the equipment it serves.

As per BS 9999, extract ductwork from kitchens does not require fire dampers and should discharge directly to the open air. Occasionally, due to building layout, this is not possible and the ductwork must pass through an adjacent fire compartment. In these cases, specific and additional fire precautions must be applied to ducting in order to maintain effective fire separation between the two compartments. This may mean that the ducting should be enclosed within a building services duct and the duct should be constructed with the highest level of fire resistance of the structures it penetrates.

An alternative solution would be to achieve the required fire resistance by designing it into the ductwork material itself by way of either a suitable protected shaft or a suitable protective material.

It is possible for a fire to ignite within the ducting itself and in these cases, fire can spread quickly due to heat radiation or direct contact of the ducting with adjacent combustibles. When planning the routing of extract ductwork, such potential hazards should be taken into account.

To assist in preventing fire from heat radiation within a duct to combustible materials, a separation of at least 150 mm, but preferably 500 mm, should be achieved and maintained between uninsulated ducting and combustible materials. Prominent notices should be displayed at all times in vulnerable locations to warn of this hazard and incorporated into all fire safety training for staff members. Where space is limited, the use of short runs may avoid the necessity for this requirement.

In part 89, LWF 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. 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.