Gas fire extinguishing agent is one of the four traditional fire extinguishing agents (water, gas, foam and dry powder). Among them, clean gas fire extinguishing agent refers to non-conductive gas or vaporized liquid fire extinguishing agent. Its basic characteristics are: gas or automatic evaporation, no residue, good electrical insulation, and no pollution to the protected object.

Chapter I main classification

The current clean gas fire extinguishing agents can be divided into five categories:

1. Halon extinguishing agent (Halon extinguishing agent (1211 / 1301);

2. Hydrofluorocarbon fire extinguishing agent (heptafluoropropane, trifluoromethane, hexafluoropropane);

3. Perfluorohexone (perfluorohexone);

4. Inert gas extinguishing agent (IG541, IG01, IG100, ig55);

5. Carbon dioxide extinguishing agent (carbon dioxide);

Note 1: halogenated alkane fire extinguishing agent, hydrofluorocarbon fire extinguishing agent and perfluorohexone are all synthetic gas fire extinguishing agents, commonly known as chemical gas fire extinguishing agents.

Note 2: heptafluoropropane is FM-200, which is a registered trademark of Great Lakes Chemical Company.

Note 3: according to the definition of relevant specifications, carbon dioxide fire extinguishing agent is not classified as clean gas fire extinguishing agent, but it has the characteristics of clean gas fire extinguishing agent and meets the definition requirements, so it is listed in this table.

• Halon extinguishing agent (Halon extinguishing agent):

Since the 1980s, halons and other substances that destroy the ozone layer have been phased out globally, and halon 1211 / 1301 has been phased out since the 1990s. In the same period, its substitute heptafluoropropane and other hydrofluorocarbon fire extinguishing agents have been widely used.

• Hydrofluorocarbon fire extinguishing agent: 1. Heptafluoropropane, trifluoromethane and hexafluoropropane belong to hydrofluorocarbons, which are synthetic chemical fire extinguishing agents. They are typical representatives of chemical gas fire extinguishing agents at present. They are highly efficient and clean. They are the most widely used chemical gas fire extinguishing agents at present.
• The current code for design of gas fire extinguishing systems (2005 Edition) only temporarily lists heptafluoropropane fire extinguishing systems. According to the requirements of the code, trifluoromethane and hexafluoropropane fire extinguishing systems need to be included in stages when the time is ripe.

3. Hydrofluorocarbons do not destroy the atmospheric ozone layer (ozone destruction potential value ODP = 0), but they all have great global warming potential. The Kyoto protocol adopted in 1997 lists hydrofluorocarbons as greenhouse gases, and China will start to restrict their use in 2024.