Types of Fires

When a fire breaks out, your immediate response is to extinguish it; however, not all fires are the same and they cannot all be extinguished in the same manner. It is important to learn about fire safety and understand the different types of fires. Fire is classified into four main classes: A, B, C and D. What type of fire you encounter depends on the material or substance that is fueling the fire.

Class A

• Class A refers to fires that burn organic materials to ash. Combustible materials that fall under this type of fire include wood, trash, non-melting plastic, rubber, paper and cloth. The type of fire extinguisher you use to put out a fire depends on what class of fire you are attempting to extinguish. You can extinguish a Class A fire with a water fire extinguisher, which contains air-pressurized water that successfully snuffs out flames.

Class B

• Class B fires burn flammable liquid, gas and melting plastic. Class B combustible materials include gasoline, propane, paint thinner, kitchen grease and oil. If you face a Class B fire, use a dry chemical or a carbon dioxide fire extinguisher to put it out. Dry chemical extinguishers contain foam or powder, while carbon dioxide extinguishers contain highly-pressurized carbon dioxide. You should use a dry chemical or a carbon dioxide fire extinguisher to put out grease fires, but never use water fire extinguishers on grease.

Class C

• Class C fires involve electrical equipment. Class C combustible materials include electrical outlets, appliances, circuit breakers and wiring. You can suffer from an electrical shock if you attempt to use water to put out an electrical fire. Instead, use dry chemical or powder fire extinguishers when confronting Class C fires. Use a carbon dioxide fire extinguisher on a Class C fire involving electronics, such as TVs and computers, since a powder extinguisher can leave a damaging residue.

Class D

• Class D pertains to unusual fires that occur with certain flammable metals such as magnesium, sodium, titanium, aluminum and potassium. Extinguish Class D fires by using only Class D fire extinguishers, which often contain sodium chloride. Use a powdered copper metal fire extinguisher on a Class D fire that involves flammable lithium and lithium alloys. Class D fires do not react well to water, and it is very dangerous to attempt to put them out with extinguishers that are not labeled Class D.