Synergistic effects of typical clean gaseous fire-extinguishing agents

Gaseous fire-extinguishing agents have received widespread attention due to their high efficiency, excellent extinguishing performance, and limited damage to protected objects. Previous attempts have mainly focused on the fire-extinguishing effect of single gaseous fire-extinguishing agents, where the synergistic use of gaseous extinguishing agents with different extinguishing agents has been less summarized. This study critically reviewed typical gaseous fire-extinguishing agents and their synergistic extinguishing effects, including Novec1230, hydrofluorocarbons (HFCs), inert or inactive gases, etc. It was known that the synergistic use of different extinguishing agents could compensate for the shortcomings of a single agent in physical or chemical fire extinguishing, reduce the amount of extinguishing agent used, the production of toxic substances, and improve the efficiency of the mixed system of fire extinguishing. Gas-gas synergy (e.g., Novec1230-C6F15N or Novec1230-CO2) can inhibit the flammability of some gaseous extinguishing agents at low concentrations and enhance the flame retardant and explosion suppressant effects of the mixed systems. Gas-liquid synergy (e.g., Novec1230-water mist or HFC-227ea-water mist) considers both the roles of rapid fire suppression and cooling of the protection object. To a certain extent, gas-solid synergy (e.g., HFC-227ea-SiO2 dry powder or N2-ABC dry powder) makes up for the poor coverage of dry powder fire extinguishing agents to achieve rapid and low-pollution fire extinguishing goals. This review offers guidance and suggestions for the efficient and clean use of extinguishing agents and the potential future direction.