The a-b-c model breaks stressful events into a sequence including all of the following except

To fight the different classes of fires, there are different types of fire extinguishers. Each has its own characteristics, capabilities, and limitations.

Three main types of portable fire extinguishers include:

Water extinguishers: Water extinguishers are filled about two-thirds with water and then pressurized with air. When used for Class A fires, these extinguishers remove the heat from the burning materials.

• Do not use water to extinguish an electrical fire. Water is a good conductor and can increase the possibility of electrocution.
• Do not use water to extinguish flammable liquid or cooking oil fires. Water is ineffective as it helps to spread the liquid and the fire.

Carbon Dioxide (CO2) extinguishers: The extinguishing media is pressurized CO2. When used for Class B and C fires, the CO2 covers the fuel by blanketing it, and stops the reaction at the surface by displacing oxygen. Be thorough when using a CO2 extinguisher. It has a moderate spray range and last only 10 to 30 seconds. A hard horn attached to the end of the spray tube helps to contain and aim the spray at the target area.

• Do not use CO2 extinguishers in confined spaces as CO2 can displace the oxygen in the air, making breathing difficult. Only use in a confined space if workers have appropriate respiratory protection.
• Do not use CO2 extinguishers for Class A fires because the fire may continue to smolder and re-ignite after the CO2 disperses.

Dry Chemical extinguishers: Dry chemical extinguishers are the most common and available in few types. These extinguishers will be marked for the classes they are designed to extinguish (e.g., ABC type extinguisher will put out Class A, B and C fires). The extinguishers discharge a blanket of fine powder which creates a break between the fuel and the oxygen in the air. The powder also works to break the chemical reaction. Be accurate when using as they have a short to moderate spray range and last only 10 to 25 seconds.

Be cautious of the residue after using dry chemical extinguishers. The residue can damage motors, computers and other electrical equipment.

Below is a summary of these and other common extinguishers.