The synergistic effect of various fluorine-based fire extinguishing agent additives

Fluorine-based fire extinguishing agents refer to agents that primarily undergo thermal decomposition during fire suppression, producing free radicals such as CF 3 . These radicals then react with H· and OH· radicals to interrupt the combustion process. In contrast, a fluorine-based fire suppression additive is a substance that enhances the extinguishing performance of a primary agent through synergistic interactions. Fluorine-based fire extinguishing agents are highly efficient and perform excellently, but they still require relatively high concentrations to achieve fire extinguishing capabilities comparable to those of halogenated fire extinguishing agents. To overcome this problem, various additives have been explored to enhance their fire extinguishing effect. Inorganic salts (dry powders) have a good synergistic effect with fluorine-based fire extinguishing agents, which can inhibit the generation of hydrogen fluoride. However, their poor solubility in many organic compounds limits their use. Common inert gases (N 2 , CO 2 , Ar) have almost no synergistic effect and are therefore not suitable for use as fire extinguishing enhancers. In contrast, fluorinated refrigerants (whose molecular structure is similar to that of the main fluorine-containing agents) are easily dissolved and generate the same fire extinguishing free radicals (such as CF 3 , CF 3 CF 2 ), thus having a strong synergistic fire extinguishing effect. This review provides an overview of these additive categories, analyzes the advantages and disadvantages of solid and gas synergists, and classifies the synergistic mechanisms based on the functional groups present in the formulation of fluorine-based fire extinguishing agents. • The review offers mechanistic insights into composite fire suppressant optimization. • Inorganic salts boost suppression and lower HF via decomposition and scavenging. • Inert gases show negative synergy by diluting radicals from the main extinguishing agent. • Fluorinated organics enhance synergy via radical scavenging and matched volatility.