Extinguishing Efficiency of Liquid Nitrogen Against Trichlorosilane Fires

TCS (Trichlorosilane, SiHCl₃ ) and other Chlorosilane were used abundantly in semiconductor and solar energy industries as the principal resource to generate ultrapure silicon in production. They are mostly acutely toxic, water-reactive and corrosive substances. While in the fires, TCS might form Silicon dioxide, Chlorine and Hydrogen gases and were difficult to extinguish. There were numerous fires due to TCS’s flammability, such as overturned truck in Michigan, US, 1989 and leaking in solar manufacturer in Pingtung, Taiwan, 2011. Many concerns aroused among the relevant agencies on how to put out fires and how to reduce hazards. Our study showed liquid nitrogen could yield extinguishing ability with its cooling and suffocation effects. Vaporizing liquid nitrogen drew the heat from combustion reaction and reduced the flammable vapor to quench flames. The key parameter was liquid nitrogen application in large amount could effectively extinguish TCS fires. Cooled TCS showed unchanged properties and still had potential to flame. Dry ice had a similar cooling effect, but required large amount, probably due to its solid keep contact area than liquid.

Keywords: Trichlorosilane (TCS), Extinguishing, Liquid nitrogen