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Abstract: The State Key Laboratory of Fire Science has been investigating bromofluoroalkenes as Halon replacements for several years. One of the leading candidate agents of bromofluoroalkenes is monobromotrifluoropropene, (CF3CBrCH2, CAS Code 1514-82-5) for its high fire extinguishing efficiency and short atmospheric lifetime. In this paper, a synthesize method for CF3CBrCH2 is studied and the purity of synthesized production is measured by Gas Chromatograph-Time of Flight Mass Spectrometer above all. And then, the conformer, bond length and bond angle of CF3CBrCH2 are calculated by ab initio method. According to calculation results, possible decomposed products in high temperature and chemical fire-extinguishing mechanisms in flame are discussed. Finally, in order to make CF3CBrCH2 release fire protection area easily, nitrogen is mixed with it to form binary fire extinguishing agent. The fire suppression ability of binary fire- extinguishing agent of nitrogen and CF3CBrCH2 is measured in a confined room. From experimental results, it is concluded that the binary fire extinguishing agent of nitrogen and CF3CBrCH2 owns higher fire extinguishing efficiency and its spray characteristics are perfect, so it is a kind of potential Halon alternatives. [Copyright &y& Elsevier]

C3H2F3Br (1323) is a new kind of Halon replacements developed by our research group. In order to improve the disperse capability of 1323, nitrogen was mixed with 1323 to form the binary fire-extinguishing agent. In this work, the binary fire-extinguishing agent of nitrogen and 1323 was used in experiment and the fire extinguishing efficiency was discussed. In addition, the fire suppression mechanism was investigated and the fire-extinguishing concentration of nitrogen and 1323 was also studied. [ABSTRACT FROM AUTHOR]

2-bromo-3,3,3 trifluoropropene (2-BTP), as a substitute for halon fire extinguishing agent, is clean, environmentally friendly and low-toxicity. However, the potential corrosiveness increases the insecurity in 2-BTP applications. Therefore, the corrosion behavior of the agent to typical magnesium alloy material AZ80A was studied at different temperatures. On this basis, corrosion products and gaseous products were analyzed, and the corrosion mechanism of 2-BTP on AZ80A at 400 °C was explained. The result shows that the pyrolysis of 2-BTP produces C3∼C5 products and HF, which corrode AZ80A to produce MgF 2 , increasing the coupon mass and reducing the ultimate tensile strength. However, the corrosion product layer adheres tightly to the alloy surface and increases the corrosion resistance. Meanwhile, the substance increases the efficiency of the agent pyrolysis. The performance assessment of the 2-BTP was refined by this work. • High temperature corrosion of the low-GWP fluorinated gas HFO-1234yf on magnesium alloy AZ80 is investigated. • Corrosion of AZ80 caused by pyrolysis of HFO-1234yf. • Corrosion products on the surface of magnesium alloy can promote the cleavage of HFO-1234yf. [ABSTRACT FROM AUTHOR]

• High temperature corrosion of the low-GWP fluorinated gas HFO-1234yf on magnesium alloy AZ80 is investigated. • Corrosion of AZ80 caused by pyrolysis of HFO-1234yf. • Corrosion products on the surface of magnesium alloy can promote the cleavage of HFO-1234yf. HFO-1234yf, as an alternative to traditional refrigerants and halon fire extinguishing agents, is environmentally friendly and low toxic. In this study, the corrosion behavior of HFO-1234yf to magnesium alloy materials was studied at high temperature. The result shows HFO-1234yf without pyrolysis is compatible with AZ80A alloy and has no corrosive effect on AZ80A alloy. The HFO-1234yf pyrolyzed at 400 °C to produce C4 products and HF. The corrosion of the alloy surface by HF caused the formation of MgF 2 , which caused increased mass and decreased ultimate tensile strength of AZ80A.On this basis, corrosion products and gaseous products were further analyzed, and the corrosion mechanism of HFO-1234yf on magnesium alloy at high temperature was explained. The results are helpful for the safe application of HFO-1234yf and screening of Halon substitute agents. [ABSTRACT FROM AUTHOR]

[Display omitted] • Inhibition mechanism of CF 3 CHCl 2 on oxygen-enriched flames of CH 4 were studied. • The increase of oxygen content lowered the inhibition effect of CF 3 CHCl 2 on burning velocity. • The effect of CF 3 CHCl 2 on chain radicals and heat release rate are higher with more oxygen. • The sensitivity coefficient of CF 3 CHCl 2 for oxygen-enriched flame is lower. In oxygen-enriched environment (oxygen concentration above 21%), flammable materials become even more flammable with higher net heat release rate, burning velocity and combustion intensity. Unfortunately, most investigations concentrated on the characteristics and mechanisms of oxygen-enriched combustion, the methods to control or weaken their perniciousness of oxygen-enriched fire have been rarely reported. CF 3 CHCl 2 (HCFC-123, R123) has been demonstrated excellent inhibition performance for oxygen-normal combustion in the fire suppression experiment, was considered as the potential fire extinguishing agents of aircraft cargo. This study performed the comparison between the inhibition performance and kinetic mechanism of CF 3 CHCl 2 for the CH 4 -N 2 -O 2 (21% of O 2) flame and the flames enriched up to 23.1%, 25.2%, 27.3% of oxygen with constant-volume combustion chamber and numerical prediction. Even for the oxygen-enriched flames, CF 3 CHCl 2 showed substantial inhibition effect on the burning velocities and adiabatic flame temperature. The chain-radicals production/consumption rate and normalized sensitivity coefficients were investigated to analyze the in-depth inhibition mechanisms of CF 3 CHCl 2 for oxygen-enriched flames. The mechanism analysis found that the inhibition effect of CF 3 CHCl 2 and relevant halogenated species on oxygen-enriched flame are smaller than that in normal flame. [ABSTRACT FROM AUTHOR]

• Material compatibility analysis between a new fire extinguishing agent and typical elastomer sealing materials. • In depth theoretical analysis of the damage mechanisms for agent-polymer interaction. • This is beneficial to the material selection of fire extinguishing system. The seals are usually used to fill the gap between the storage containers and discharge pipes in the built-in fire extinguishing system of the aircraft. These seals inevitably touch the fire extinguishing agents, which may reduce the hermeticity of seals. In this paper, the compatibility experiment of 2-bromo-3,3,3-trifluoropropene, a new clean fire extinguishing agent, with fluorosilicone rubber and fluoro rubber was performed at 25 ℃, 0.1Mpa. The volume, weight, hardness, and mechanical properties of the sealings were tested, and the changes in cross-section and infrared spectrum were analyzed. The results show that during the contact with 2-bromo-3,3,3-trifluoropropene, fluoro rubber is damaged more severely than fluorosilicone rubber, the hardness measured directly and after drying decreased by 12.9 % and 17.6 % respectively, while the tensile strength decreased by 51.2 % and 86.1 % respectively. It is proved that 2-bromo-3,3,3-trifluoropropene have poor compatibility with the fluoro rubber and fluorosilicone rubber. [ABSTRACT FROM AUTHOR]