The LWF Blog

Fire Engineering Design and Risk Assessment – Agents used in Gaseous Systems – Part 11

July 12, 2018 2:10 pm

In LWF’s Fire Engineering and Risk Assessment blog series for architects and others in the building design business, we have been looking at gaseous systems as a method of fire suppression. In part 10 of this series, the required configuration of gaseous systems was outlined and in part 11, the agents used in such systems will be discussed from the point of view of safety and the environment.

 

After the banning of halon 1301 for widespread use, clean agent replacements were assessed for safety issues by the Halon Alternatives Group, as a part of DEFRA. A report was produced in 1995 and updated in 2000 named ‘Review of the toxic and asphyxiating hazards of clean agent replacements for halon 1301’.

 

Fire situations generate thermal decomposition products which can be toxic and corrosive. In the case of halocarbon clean agents, the main thermal decomposition product is hydrogen fluoride. Where the system is correctly designed, it is not anticipated that hydrogen fluoride would cause any damage or losses of any consequence.

 

As inert agents do not decompose they do not produce corrosive decomposition products, however, the fire itself can cause combustion products which can be significant and could make the area in question uninhabitable.

 

Looking at the potential for impact upon the environment, the ban on halons by EU Regulation EC 1005/2009 and the banning of hydrochlorofluorocarbons (HCFCs) meant that all chemical agents must have zero ozone depletion potential.

 

The EU’s commitment to reduce greenhouse gases resulted in EU Regulation EC 842/2006 which covers the hydrofluorocarbons (HFCs) used in fire protection. This has since been repealed and replaced by Regulation (EU) No 517/2014 of the European Parliament and of the Council of 16 April 2014.

 

While it is possible to have a gaseous fire protection system using an HFC such as FM200, Ecaro 25 or FE 13, such systems should only be used where other systems that are suitable for purpose, safe, technically feasible, cost-effective and more environmentally acceptable are not possible.

 

As there are no critical applications for HFCs which cannot be provided by other environmentally sustainable systems such as water mist, inert gas, Novec 1230, aerosols, high-sensitivity smoke detection etc., the potential need for use is very small.

 

In part 12 of this series, LWF will look at the types of halocarbon agents. 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.