Junchao Zhao,Zhitao Yin,Muhammad Usman Shahid,Haoran Xing,Xudong Cheng,Yangyang Fu,Song Lu
The re-ignition of pool fires is a common hazard phenomenon in fire extinguishing. Dry chemicals with oleophobicity may solve this problem because powders can float on the oil surface and prevent evaporation of fuel pool. In this research, MAPP (modified ammonium polyphosphate) with superhydrophobicity, oleophobicity, and higher chemical activity is prepared which can quickly quench pool fires and provide longer protection. The activation indexes of MAPP for water, diesel , aviation kerosene and gasoline are 98.5%, 87.4%, 98.7% and 98.4%, respectively. Lower activation energy of MAPP means that it will show higher chemical activity in fire. The fire-extinguishing performance of MAPP is much higher than that of Commercial UDCA (ultra-fine dry chemical agent) during fire experiments. After extinguished by MAPP, the fuel pool is hard to be re-ignited. The significance of this study is to propose a new strategy for preventing the re-ignition of pool fires.
Long Yan,Jingjing Guan,Ning Wang,Zheng Wei,Zhisheng Xu,Guoqing Niu
To meet the environmental requirement of foam extinguishing agent, a novel fluorine-free surfactant named amino-terminated polyether modified silicone (ATPMS) was successfully synthesized, and then in combination with hydrocarbon surfactant prepared fluorine-free foam extinguishing agent. The study carefully investigated surface tension, foamability, foam stability and fire extinguishing performance of fluorine-free foam extinguishing agent. The results indicate that ATPMS has a low surface tension of 21.17 mN/m, which combined with hydrocarbon surfactant at the mass concentration ratio of 1:1 imparts high surface activity. The sodium lauryl ether sulfate (AES)/ATPMS system owes the optimal comprehensive performance with an initial foam height value of 85.8 mm, a surface tension value of 24.76 mN/m and a foam stability value (the ratio of foam height between initial foam and five-minute foam) of 64.0 % at critical micelle concentration ( CMC ), respectively. Fire suppression test shows that the obtained fluorine-free foam extinguishing agent is effective in fighting diesel pool fires. The firefighting efficiency of foam agent links to the mixing chamber structure of compressed air foam fire extinguishing system (CAFS). When the mixing chamber of CAFS has a recurrent segment length of 50 mm and the filled particle size of 10 mm, the firefighting efficiency of fluorine-free foam extinguishing agent is optimal with a fire extinguishing time of 33 s and a temperature drop rate of 6.49 °C/s.