Fire extinguisher five categories. In the UK the use of Halon gas is now prohibited except under certain situations such as on aircraft and in the military and police. Fire extinguishing performance per fire class is displayed using numbers and letters such as 13A, 55B. EN3 does not recognise a separate electrical class - however there is an additional feature requiring special testing (35 kV dielectric test per EN 3-7:2004). A powder or CO extinguisher will bear an electrical pictogramme as standard signifying that it can be used on live electrical fires (given the symbol E in the table). If a water-based
Cutting extinguisher smoke diving is reduced. The small size of the access hole also reduces any risk of flashover or backdraft. Flashover is reduced by avoiding the need to open up a large access hole, backdraft by the flow of water through this small hole keeping any flow cooled and directed inwards, towards the fire. Secondary advantages are in gaining rapid access to the seat of the fire, directly through most construction materials and without needing to cause structural damage that may further weaken a structure. The cutting extinguisher technique originates in Sweden, with Cold Cut Systems Svenska AB. Cold Cut Systems