Fire extinguisher older models also achieved class B and C fire-fighting capability in the past, current models are rated A:K (Amerex, Ansul, Buckeye and Strike First) or K only (Badger/Kidde). Clean agents extinguish fire by displacing oxygen (CO or inert gases), removing heat from the combustion zone (Halotron-1, FE-36, Novec 1230) or inhibiting the chemical chain reaction (Halons). They are referred to as clean agents because they do not leave any residue after discharge which is ideal for protecting sensitive electronics, aircraft, armored vehicles and archival storage, museums, and valuable documents. Halon was completely banned in Europe and Australia except for critical
Chubb Fire 1912–1918 The North Metropolitan Electric Power Supply Company carried out a series of stringent tests on the 'Petrolex' extinguisher and informed Read and Campbell that, 'I have never seen any fire extinguishing appliance that seemed as well suited and effective for dealing with fires in Electrical Stations'. Further patents were granted in France and Brazil during this period. In 1914, foam compound was registered in Great Britain. Read and Campbell introduced their 'Rocsuds' which was an early form of foam extinguisher. The contents were, amongst other things, saponin, derived from the roots of soapwort, sodium bicarbonate, extract of vegetable syrup