Home » Mather + Platt » Fire engineering » Halons


Three types of Halon gas were used for extinguishing fires, though all have now been prohibited by the Montreal protocol as they were found, along with other chemicals, to be destroying the Earth's ozone layer. Each Halon has a four-digit designation that indicates, respectively, the number of fluorine, bromine and chlorine atoms they have and their base hydrocarbon group. The three types are

HalonFluorineBromineChlorineAlkane Base
1301 (tribromofluoro- methane)12 yes 
2402 (tetrabromodifluoro- ethane)24  yes
1211 (dibromofluorochloro- methane)121yes