The LWF Blog

Fire Engineering Design and Risk Assessment – Gaseous Systems – Part 9

June 28, 2018 12:13 pm

In LWF’s fire engineering blog series for architects and others in the building design industry, we have been looking at methods of fire suppression. In part 8, we finished looking at Foam Systems. In part 9, we will discuss the types and uses of Gaseous Systems.


Gaseous systems are those fire-fighting active protection systems whereby the agent used to extinguish fire is applied in a gas form. Gaseous systems can be used to protect areas with electrical risks, such as communications equipment, server rooms and Electronic Data Processing (EDP) Facilities. They can also be found useful in Class A hazard areas which would include hazards from paper, wood, plastic and Class B hazards, like flammable liquid fires.


In the past, halon was a popular gaseous agent, but as its use is now strictly limited to a very few circumstances, such as the Channel Tunnel, substitutes were found in agents from one of two classes – halocarbon or inert.


Halocarbon gases act to absorb heat, but also may have some chemical effect on the flame combustion reactions. Inert agents are designed to reduce the oxygen to below the level at which fires can continue to combust.


Gaseous systems can be classed as having the following objectives:


 To extinguish a fire

 To limit the spread of a fire

 To limit the damage caused by fire

 To prevent re-ignition of a fire previously extinguished

 To enable day to day operations to continue in short order


There are some secondary benefits to the use of gaseous systems when compared to other forms of fire suppression, namely that there is a limited amount of smoke produced and as they are ‘clean agents’ there will be no additional post-fire clean-up necessary due to the method of agent application.


Some reference documents in the UK and abroad for gaseous systems are as follows:


BS EN 15004-1:2008 – Fixed firefighting systems. Gas extinguishing systems. Design, installation and maintenance


BS 5306-4:2001+A1:2012 – Fire extinguishing installations and equipment on premises. Specification for carbon dioxide systems


NFPA 2001 – Standard on Clean Agent Fire Extinguishing Systems


Aside from the first two documents being produced as British Standards for European use and the third by the NFPA in the US, a further difference is that the BS EN standard requires higher Class A concentrations than the NFPA reference, due to increased safety margins and different test methods.


In part 10 of this series, LWF will look at system configurations for gaseous systems. 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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