Conclusion

In view of the environmental friendliness, low boiling point and low toxicity of CF3I, it could be a potential Halon substitute for fire-extinguishing agent in aircraft. In this paper, DFT calculations were performed to theoretically investigate the thermal decomposition and fire-extinguishing mechanism of CF3I, which suggest that CF3I and its decomposition products can further react with active OH· and H· radicals existed in flame through various pathways. Remarkably, through DFT calculation and reaction kinetics analysis, the fire-extinguishing radicals CF3· and I· are more easily generated during the interaction between CF3I and flame, which can react with the active OH· and H· radicals to achieve the purpose of rapidly extinguishing fire.
To explore its actual fire-extinguishing effect, we also measured the FEC of CF3I on methane-air flame. The experimentally measured FEC of CF3I on methane-air flame is 3.42vol%, which is lower than those of three HFCs and HFO-1336mzz(E), and is comparable to that of Halon 1301. Due to the pronounced fire-extinguishing performance, environmental friendliness, and promising thermal stability and storability, the CF3I agent is a recommendable candidate for Halon, which is worthy of further evaluation and confirmation of its practical applications in fire suppression process.