Abstract: Trifluoromethane (CF3H, HFC-23), as one of important perfluoroalkanes, is used commonly in now fire extinguishing agent market. However, when CF3H is discharged into the fire protection place, HF will be produced by the interaction between the flame and CF3H. HF not only has severe erosion to the metal apparatus, but also makes serious harm to the people in fire scene, so the production amount of HF in fire extinguishing protection is an important problem when CF3H is applied. At present, there is lacking of in-depth insight of HF production in fire extinguishing process with CF3H. So the amount and mechanism of HF production in fire extinguishing process using CF3H is studied in this paper. Firstly, the decomposition of CF3H under different temperature is calculated by Ab initio method at B3LYP/6-311 + + G (d, p) level. And then, the model for predicting HF amount is proposed on the base of calculation. Thirdly, the production amount of HF is measured real-timely by in-situ spectral diagnostics method when CF3H is discharged into Cup-burner with steady alcohol flame. Conclusion: By comparing the calculated results with experimental results, it shows that the HF production predicting theory model was reliable; When the temperature is lower than 100℃, there little HF；The fastest HF production rate between 100℃ and 400℃；after 400℃, it has nearly no change; The main pathway for HF production is CF3H+?H reaction.

Key words: Halon replacement, CF3H (HFC-23), HF production amount, Prediction model, Cup-burner