Fire and explosion suppression

A method of suppressing a fire or explosion, in which a fire or explosion suppressing chemical substance which is in liquid form or substantially so at normal temperatures and pressures is dispersed as a suspension in a fire or explosion suppressing gas and discharged with the gas into an area to be protected, comprising:

• producing a mist of the chemical substance and entraining the mist in the gas, the production of the mist and the entrainment of the mist in the gas taking place before the discharge of the suspension into the area to be protected;
• and
• said discharge comprising discharging said suspension into an area to be protected;
• the chemical substance comprising one or more chemicals of the structure Z-R-X-Y, where the monovalent radical Z is a halogen atom taken from the group fluorine (—F) or bromine (—Br);
• where the divalent radical R is a perfluoro- or polyfluoro-alkylidene group of formula —CnHpF2n−p—, with n in the range 1 to 6, and p in the range 0 to 4;
• where the divalent X is either an enther linkage, —O—, or an alkenic linkage, —CW═CH—, with W being either hydrogen (—H) or bromine (—Br);
• and where the monovalent radical Y is selected from the group hydrogen (—H), bromine (—Br), or alkyl of formula —CmH2m+1 with m in the range 1–4 or perfluoroalkyl of formula —CmF2m+1 with m in the range 1–4 or polyfluoro-alkyl group of formula —CmHkF2m+1−k where m is in the range 1–4 and k is in the range 1 to 2m;
• and with the provisos that (i) there is always one, and only one, bromine atom in the chemical Z-R-X-Y, and that (ii) the total number of carbon atoms in the chemical Z-R-X-Y is in the range 3–6;
• and the chemical substance having an atmospheric lifetime of less than 30 days.