Generally, two types of gaseous fixed Fire Suppression systems are available for enclosures these being:
Oxygen reduction systems that use inert gases such as Argon, CO2, Nitrogen or a combination or all three.
Gaseous clean agent systems that cool and breakdown the chemical reactions in fire.
Clean agent systems include gases such as FM200, Novec 1230, FE13 & Proinert. Due to environmental issues, these gaseous clean agent systems have replaced Halon 1301 as an extinguishing agent. Gaseous extinguishing systems should be installed by companies that have F-Gas Certified certification schemes, which prove their competence in that area.
Gaseous clean agent fire extinguishing systems are used for computer rooms and EDP; indoor transformers and switchgear; telecommunications, generators; engine and turbine enclosures, and flammable liquid stores. CO2 systems are used for areas where, electrical hazards, flammable or combustible materials may be present but which are not normally occupied.
Typical applications include turbines, machinery, silos switchgear and similar electrical hazards. Generally gaseous fire protection systems are operated by specific automatic fire detection systems in which detector provision and spacing is configured to give very early detection. Usually a “double knock” activation of two detector heads is necessary to discharge the gas. A warning is normally given in the protected area before the gas discharges to allow personnel to leave the area.
The fire detection and Fire Suppression systems will normally be operated in an air conditioned and heated environment; however they shall be capable of operating within the temperature range of –10oC to +40oC in order to cater for an environmental control system failure.
In relation to extinguishing systems the design criteria would be:
- BS5839 2003 Part 1 – Fire detection & Alarm Systems For Buildings
- BS6266: 2011 – Code of Practice for Fire Protection for Electronic Equipment Installations
- BS 7273-1:2006 – Code of Practice for the operation of fire protection measures
- ISO 14520-1/14 – Gaseous Fire Extinguishing Systems
- BS EN 15004-1 2008 – Fixed Fire Fighting Systems – Gas Extinguishing Systems
- Requirements of the Authority Having Jurisdiction (AHJ)
Most important is the System Extract
It is preferred when extracting a discharge of a Fire Suppression System that a suitably sized extract fan complete with ductwork be installed out to fresh air. The position of the extract grill must be positioned in such a manner that the extract will not extract into either an enclosed volume or into an area where people can walk directly into the path of the vented air. The recommended air changes per hour for this extract should be a minimum of 2 complete air changes. It should be noted that we as a company DO NOT carry out this extract work this MUST be carried out by others.