If there is any debris or particles present in the Fixed Gaseous Fire Extinguishing Systems pipework, it will be pushed through the pipework on system discharge and can collect in the nozzles at the end of each pipe run. 

This can lead to possible blockage of the nozzle(s) and consequentially adversely affect the uniform achievement of the correct extinguishant concentration. 

Fine particles may be discharged through large orifice nozzles and if in sufficient quantity, may contaminate the protected area/asset. 

Dirt traps are required by the relevant standards – BS EN 15004-1, BS 5306-4, and ISO 14520-1 – as a means of addressing the possible blockage of nozzles. 

To help guide the industry, the FIA has developed a Guidance Note called ‘Pipe Cleanliness and the requirements for dirt traps’.  The document has been created to advise on best practice.  It discusses sources of contamination, contamination removal, contamination avoidance, and gives further guidance on the construction of dirt traps.

The document has been created by members of the FIA’s Extinguishing Council.

Robert Thilthorpe, Technical Manager at the FIA and Secretary to the FIA Extinguishing Council, said: “People often forget the little things when installing and maintaining Fixed Gaseous Fire Extinguishing Systems. This guide reminds end users and contractors of the importance of this step in the process.”

Alan Elder, of Tyco, a Member of the FIA who sits on the Extinguishing Council said: “Often the dirt trap is not installed because people don’t realise why a dirt trap is important.  However, the standards do require a dirt trap to be installed.  Pipework can easily get contaminated by rust or dust.  When the system activates, that debris can block the discharge nozzle.”

Using the FIA guide, readers can find out more about why a dirt trap is important and how to install one.

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