Suppression technicalities

Fire Buyer Live media partner, FSSA, discusses exclusively for Fire Buyer the technical aspects of gaseous fire suppression systems 

The FSSA are a specialised suppression systems association dedicated to educating the industry in suppression equipment, techniques and materials. The FSSA is a media partner of the must-attend, virtual event Fire Buyer Live. As a media partner they will also be supporting the conference agenda with a dedicated speaker, Lance Henry from Stat-X who will discuss extinguishing agents and their role in special hazard fire protection. Continuing this theme, Lee Kaiser, PE, Chairperson of the Fire Suppression Systems Association (FSSA) Technical Committee explores the technicalities of gaseous fire suppression. 

The activation of a gaseous fire suppression or extinguishing system at a facility requires a nuanced approach from trained responders. Gaseous fire suppression systems discharge compressed gasses of various types to extinguish fires in a room, specialty enclosure, equipment housing, or directly onto a piece of equipment. Water-based fire protection system activations are relatively common for fire department responses, but the routines which may be used for response to a water-based system activation may not be appropriate for response to a gaseous system release. In any fire jurisdiction, gaseous suppression systems are likely to be encountered less frequently than water-based systems. This article offers some considerations which may be particularly appropriate when responding to a fire where a gaseous agent system has deployed.  

Basic safety considerations  

Gaseous systems include clean agents, Halon 1301, hybrids, and carbon dioxide extinguishing systems. Clean agents are further subdivided into halocarbon agents and inert gas agents. Gaseous agent systems are most frequently installed to protect specific hazards, known as a “protected space,” which require a non-water-based agent for asset protection — therefore the addition of water by the fire department is generally undesirable. Gaseous systems primarily extinguish fires through heat absorption. The fire extinguishing gasses generally will remain in the enclosure for a period after the agent discharge ends.  

The gas that remains in the hazard’s air presents a unique situation for arriving firefighters and for the building occupants. Carbon dioxide (CO2) presents a specific threat of asphyxiation for anyone in an area where the CO2 remains, both during and after the discharge. Although other agents such as clean agents, Halon, and hybrid media, in and of themselves present minimal real physical threat to occupants, toxic products of combustion from the fire as well as possible products of decomposition from halogenated agents may remain. Therefore, firefighters should enter the hazards wearing self-contained breathing apparatus (SCBA) to verify that fire has been extinguished and verify that no personnel were trapped by the fire. SCBA should be worn until the hazard has been adequately ventilated.   

Assessing the hazard  

Codes require signage to be present in spaces protected by gaseous fire suppression systems, identifying the specific agent installed. Firefighters should look for and read these signs. As part of the fire protection plan, facility managers should inform the local fire department of the presence of gaseous extinguishing systems in the facility. It is likewise advisable for firefighters to be informed of actions to be taken regarding ventilation of areas protected by gaseous systems.  

Discharge warning strobes or beacons are typically installed to warn responders that a discharge inside a room has occurred. An active discharge beacon is a good reminder to use proper personal protective equipment when entering a space to investigate.   

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