The LWF Blog

Fire Engineering for Healthcare Premises – Smoke spread and control – Part 15

December 29, 2020 1:43 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 14 of Fire Engineering for Healthcare Premises, LWF looked at smoke spread and control. In part 15, we discuss smoke curtains and smoke venting as per HTM 05-03.

Smoke curtains are an active fire safety solution which keeps smoke within an area and does not let it spread to adjoining areas. The purpose of retaining the smoke in one area is sometimes to channel it towards an extraction point, so that the tenability of conditions outside of the smoke curtains can be retained and building occupants are able to evacuate the building or area.

In a healthcare environment, the operation of the smoke curtains should be fail-safe or at least highly reliable. The curtain material must tolerate the design temperatures of the smoke layer, which can be typically greater than 200oC, except in the case of channelling screens where the temperature may exceed 600oC.

The operation of the curtains should not endanger building occupants.

A smoke ventilation system for a healthcare building must be designed in conjunction with the rest of the building’s fire protection system. The design fire determination must be carefully made and considered and the fire resistance level of the ductwork chosen appropriately.

A fusible link can be attached to the damper melts and, as the temperature of the smoke increases, the link releases and the vent will open. Such devices are often used as a last-chance backup when primary opening devices have failed in the UK.

Smoke and heat exhaust ventilation systems (SHEVs) must be designed with the overall fire safety strategy in mind, it is not sufficient to simply determine the correct fan capacities. Their purpose is to channel smoke and heat out of a burning building and keep passages and escape routes clear of smoke for the escaping occupants and to ensure tenability for firefighters entering the building.

In complex or unorthodox cases and in those cases where safety factors appear marginal, the SHEV design calculations should be verified through a third-party review, and/or hot smoke tests.

In Part 16 of LWF’s blog series, LWF will continue looking at smoke spread and control through replacement air systems, pressurisation and depressurisation. 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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