Fire extinguishers are classified according to the type of fire. jThe A, B, and C ratings define what kind of burning materials each fire extinguisher is designed to quench.
Class B fire extinguishers are effective against flammable liquid-form fires. Examples of which are cooking oils, gasoline, kerosene and the like. There are two commonly used effective fire-fighting chemicals used in these types of fire namely monoammonium phosphate and sodium bicarbonate. The monoammonium phosphate can effectively smother the fire from these liquid combustibles while the sodium bicarbonate induces a chemical reaction to extinguish the fire.
Therefore, the Class B fire extinguishers are suitable for liquid form combustibles such as cooking oil, gasoline, kerosene or paint.