The LWF Blog

Fire Safety for Facilities Management Personnel – Foam Systems – Part 247

April 8, 2024 9:49 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 246, LWF discussed water mist systems and the various legislation and guidance documents covering them. In part 247, we will look at foam systems.

A foam fire suppression system is one in which the foam is a fire extinguishing agent, capable of extinguishing flammable or combustible liquid by cooling and separating the ignition source from the surface. The foam suppresses and smothers fire and vapours and can prevent re-ignition.

The foam itself is comprised of water, air and a suitable foaming agent. Low and medium expansion foams can be found primarily in use where there are quantities of flammable liquids, either in use or storage.

Foam systems tend not to be used in general commercial and industrial buildings, but may be used in an oil-fired boiler room.

High-expansion foam systems are intended for use where the entire volume of a space should be filled with foam to protect class A risks. This is particularly useful where an area would be inaccessible by firefighters for firefighting purposes.

A high-expansion foam system may be used to protect warehouses, engine rooms, transformer buildings, cable tunnels, underground storage etc.

Each foam suppression system should be custom-designed for the space and hazard it must protect, further information on the design of expansion foam systems can be found in BS 5306, parts 6.1 and 6.2, accessible from the BS 5306 landing page.

Two particular types of foam can be used to discharge from a sprinkler installation. Aqueous filmforming foam (AFFF) and filmforming fluroroprotein foam (FFFP) can provide a more effective protection than simple water in certain environments, for example, a warehouse where a large inventory of relatively low-flashpoint flammable liquids are stored.

The sprinkler system in question would be designed largely as a conventional installation with facilities for inducing the AFFF or FFFP liquid into the water supply.

In part 248 of this series, LWF will begin to discuss Gaseous Systems and the relevant applications. 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 35 years’ experience, which provides a wide range of consultancy services to professionals involved in the design, development and construction and operation of buildings.

 

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.