Water mist breaks water into very fine droplets. Minimax explains that the small droplets spread over a larger surface to absorb the heat of the fire, block radiant heat from reaching unburnt fuel, and cool the flame and surrounding gases while displacing oxygen as they evaporate.
The foam based water mist extinguisher is a 9 L unit charged with water and foam, pressurised with nitrogen at 15 bar and rated 4A, 233B and 75F. The A figure relates to solid material fires, B to flammable liquid fires and F to cooking oil fires, so one unit covers a mixed risk area. Its cylinder is tested at 35 bar.
The CAFS backpack is carried on the back for first intervention. It holds 9 L of potable water with 6 percent AFFF (aqueous film forming foam), driven out by air stored in a 2 L cylinder at 200 bar. Minimax lists a 55A 233B rating, a 14 m jet, a minimum effective discharge time of 23 seconds and at least 95 percent effective discharge.
Both units are listed for use from +5 °C to +60 °C, so keep them in areas within that range. FPS supplies, installs and services them in Bhopal and across Madhya Pradesh.