Fires involving organic solid materials such as wood, cloth, paper, plastics, coal etc. Water has a great cooling effect on the fuel’s surface and thereby reduces the pyrolysis rate of the fuel
They are mainly water based, with a foaming agent so that the foam can float on top of the burning liquid and break the interaction between the flames and the fuel surface.
The ABC Dry Powder (or Dry Chemical) charged fire extinguisher is most used and most popular multi-purpose fire extinguisher, that are filled with powder and pressurized with nitrogen and can be used on Classes A, B & C fires. Powder fire extinguisher are color coded with a blue label. Dry Powder fire extinguishers extinguish the fire by smothering the flames.
Carbon dioxide extinguishers work by suffocating the fire. Carbon dioxide displaces oxygen in the air. However, once discharged, the CO2 will dissipate quickly and allow access for oxygen again, which can re-ignite the fire.
Wet chemical fire extinguishers are ideal for Class F fires, involving cooking oils and fats, such as lard, olive oil, sunflower oil, maize oil and butter.