The LWF Blog

Fire Safety for Healthcare Premises – Ventilation Systems – Part 40

September 20, 2018 12:55 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 39, compartmentation and fire hazard areas and rooms were discussed and in part 40, we move on to look at the use of ventilation systems in healthcare venues and how this is affected when there is a fire situation.


Mechanical ventilation can be used in any kind of building but is particularly used extensively in the healthcare sector. The reasons for use are varied, including specialist systems in operating departments, critical care areas and isolation rooms, to ensure compliance and quality control in pharmacy and sterile services departments and to protect staff from breathing in harmful or toxic substances in labs and other areas.

While mechanical ventilation is designed primarily to remove toxic elements and provide clean air, its design can be potentially harmful in the event of a fire. A fire produces large quantities of smoke and gases which can be transferred through the ventilation ductwork into other areas remote from the source.

For this reason, measures should be put in place to limit the spread of fire, smoke and other products of fire through the ductwork between protected areas. Such measures must also prevent breaches in the integrity of compartmented construction where the ductwork penetrates it, to retain fire-resisting properties.

Information on how ventilation systems should be designed in order to meet these requirements can be found in HTM 03-01 ‘Specialised Ventilation for Healthcare Premises’ (PDF) and also in BS 9999:2017 – Fire safety in the design, management and use of buildings. Code of practice (formerly BS 5588-9).

Where ventilation systems are to be used in both patient areas and hazard departments, they should not be common and fresh air intakes should be positioned to avoid the potential for the intake of smoke and toxic gas from any other source.

Fire and Smoke Dampers

In order to maintain the level of fire-resistance in place, ventilation ducts must maintain the level of fire-resistance of the surrounding construction. Such areas may include fire hazard rooms, sub-compartments, compartments, cavity barriers and protected shafts.

The type of dampers required may vary depending upon area of use and purpose. They are as follows:

Fire and Smoke Dampers which are activated by AFD should be used in compartment floors, compartment walls, protected shafts, sub-compartment walls, cavity barriers and fire hazard rooms.

Fire Dampers with Thermal Activation should be used for cavity barriers and fire hazard rooms.

Air transfer grilles for cold smoke activated by AFD should be used in fire hazard rooms, doors to fire hazard rooms and doors in sub-compartment walls.

Air transfer grilles with thermal activation should not be used in any of the above listed areas and should not be fitted in fire doors unless accompanied by a test certificate provided by the door manufacturer. The reason they are not recommended for other uses is that those dampers and grilles activated by a fire alarm provide a more responsive containment environment and are therefore always preferable.

In part 41 of this series, LWF will continue looking at Fire and Smoke Dampers. 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.


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