3. Results and discussion
3.1 Fireextinguishing concentration
On account of the boiling point of R123 (27.9 °C) exceed normal temperature, the fire-extinguishing experiment was performed under the heating condition. Herein, the calculation of minimum extinguishing concentration (MEC) should consider the temperature and pressure compensation. The temperature mainly influenced the gas flowed, so except for the flowmeter’s conversion coefficient, the calculation required temperature and pressure compensation to calculate the actual flow. Based on the above consideration, the average MEC of R123 on methane fire was calculated as 7.31 %, the result is similar to reported results. By using the same cup burner test, the extinguishing concentration of R125 on methane fire under the normal temperature and pressure was 8.91 % by standard method calculated. Compared with the results of R125, R123 has a lower MEC, which indicates the better efficiency of fire suppression of R123.