which type of fire requires foam/dry chemical as an extinguishing agent?

　　Foam extinguishing agents are mainly suitable for extinguishing the following types of fires:

　　Class A fires: These are fires in solid materials, such as wood, paper, fabric, rubber and some plastics.

　　This type of fire usually produces ash when burning, and the foam extinguishing agent can cover the surface of the burning material, isolate the oxygen and cool the burning material, so as to extinguish the fire.

　　Class B fires: fires in liquids or melting solids, such as gasoline, diesel, paint, alcohol and other flammable liquids.

　　Foam extinguishing agents can form a layer of foam cover on the surface of these liquids to isolate the air, prevent volatilization, and cool the liquid fuel to prevent re-ignition.

　　Foam extinguishing agents are usually not suitable for the following types of fires:

　　Class C fires: These are gas fires, such as natural gas, acetylene, and hydrogen. This type of fire requires the use of dry powder extinguishers or carbon dioxide extinguishers.

　　Class D fires: refers to metal fires such as magnesium, titanium, sodium, potassium, etc.

　　These fires generally require the use of specific dry powder extinguishing agents.

　　Class E fires: refers to electrically charged fires (some classification systems refer to these fires as Class C fires), i.e., electrical equipment fires. Foam extinguishing agents are electrically conductive and their use on energized equipment may result in a shock hazard; dry powder extinguishers or carbon dioxide extinguishers are typically used.

　　Class F fires: These are cooking grease fires, such as cooking oil and fat fires in the kitchen.

　　These types of fires are suitable for the use of specially designed wet chemical extinguishing agents.

　　Foam extinguishing agents are suitable for extinguishing Class A and B fires, but should be used with attention to the specifics of the fire scene and safety matters.