The LWF Blog

Fire Safety for Facilities Management Personnel – Structural Fire Protection – Part 155

June 20, 2022 11:07 am

Lawrence Webster Forrest (LWF) is a specialist fire engineering and fire risk management consultancy whose aim is to give information on best practice in fire safety for facilities management personnel through this blog series. In part 154, LWF looked at structural fire protection and doors for fire safety. In part 155, we continue to discuss fire and smoke resistant doors.

Fire-resisting doors are designed to stop fire and its products from passing from one side of the door to the other, providing separation for a period of time indicated. They are not, unless specifically stated, insulated and so the side of the door opposite the fire is likely to become heated. Indeed, the thermal radiation from the unexposed face of the door may be sufficient to ignite any nearby combustible materials. It is important that such materials are not placed in close proximity to an uninsulated door.

It may be that an insulated door would be an appropriate installation decision. When installing a door to a room containing sensitive electronic equipment, for instance, it is likely to be worthwhile to install an insulated door to prevent the transmission of heat through the door which may damage the equipment contained within.

It is also worth considering smoke seals on doors for other than life safety purposes. Smoke can also cause serious problems with sensitive electronic equipment, for example.

Fire doors are indicated by the letters ‘FD’ and the letters are followed by a number indicating the intended duration of integrity, e.g. FD30. Where a door is also intended to stop the passage of smoke, it will be designated FD30s.

Some doors are tested under the relevant European standard. Under BS EN 1634-1 test regimes, a door which withstands fire attack for a period of time, for example 36 minutes or 67 minutes, for the purposes of regulations is then described as E30, E60 etc. Smoke restriction in this case would be indicated by the suffix Sa, e.g. E30Sa.

BS 9999 contains recommendations for which fire-resisting doors should be used for specific purposes.

The following recommendations are made for fire door purposes and suitability:

For FD30 – lift shafts which are enclosed in fire resisting construction and fire doors to external fire escape stairways.

For FD 30S – Fire doors to protected stairways, lobbies etc.; some ancillary accommodation such as plant rooms (although for others, FD60S may be required); service ducts.

For FD20S – dead-end corridors; cross-corridor fire doors.

It should be noted that general recommendations cannot take into account specific circumstances within a building and so an overall fire engineering design may make recommendations based on the presence of specific hazards or mitigating fire safety provision.

In part 156 of this series, LWF will continue to look at fire doors.  In the meantime, if you have any queries about your own facilities or wish to discuss this blog series, please contact LWF on freephone 0800 410 1130.


Lawrence Webster Forrest is a fire engineering consultancy based in Surrey with over 25 years’ experience, which provides a wide range of consultancy services to professionals involved in the design, development and construction and operation of buildings.

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