Foam Fire Extinguishers are mainly consists of water with a foaming agent. The foam can control the fire when it floats on the top of the burning liquid, and insulate the flames from fuel surface.
Foam fire Extinguishers are effective to deal with fires from class A & B. Although this type of Fire Extinguishers are not really recommended for fires including electricity, but are still considered to be safer than water on live electrical fires.
Where to use Foam Fire Extinguishers system? We can use Foam Fire Extinguishers with solids and burning liquids, including paint and petrol. The major advantage here that we can use Foam Fire Extinguishers on fires caused by electricity if tested to 35kV.