First choose water or foam by the fire risk. Water is for Class A fires in solids such as wood, paper, fabric and plastics, and a water jet must not be used on live electrical equipment or burning oil. Foam covers Class A and Class B, so it suits mixed risks such as garages, fuel stations, paint shops, warehouses and factories. Where alcohols, ketones, solvents or other water soluble liquids are stored, choose AR-AFFF, offered by Minimax in 9 L and mobile units and by Kanex in trolley units.
Next decide between jet and spray. Ceasefire spray models break the agent into a fine spray that is listed for live electrical equipment up to 1000 V from 1 metre, and some add an F rating for cooking oil: the BIS water spray model is rated 3A, 25F and the BIS foam spray model 2A, 89B, 25F. Ceasefire also offers fluorine free foam, free of PFOS and PFOA, and a fluorine free foam mist listed for Class A, B, F and electrically started fires.
Then choose stored pressure or cartridge operation and the body. Stored pressure units hold nitrogen in the cylinder, with a pressure gauge to check the charge. Cartridge units keep CO2 in a separate cartridge and are pressurised only when used, which Minimax notes makes refilling quick and suits industrial and outdoor sites. Stainless steel bodies from Ceasefire, Kanex (HQ series) and Minimax suit display areas and coastal or high salinity locations, while Balaji Fire Safety lists mild steel bodies on its 9 litre units and 50 litre trolley.
Finally match size and rating to the area. Portable units run from 2 L (Minimax water) to 9 L, including Balaji Fire Safety 9 litre water and AFFF foam units, with the AFFF unit rated 3A and 89B. Trolley units run from 20 L to 100 ltr: Minimax 20 and 60 L, Savemax 25 and 45 litre foam, Balaji Fire Safety 45 and 50 litre AFFF foam, Kanex 45 and 60 Ltr AR-AFFF rated 20A:233B with about 9 m throw, Kartar Valves 45 L foam, and Ceasefire 50 and 100 ltr units to EN 1866 plus 60 ltr units to IS 16018. Ratings change with agent, size and test standard, so check the listed figure against your fire NOC.