Types and Classes of Fire Extinguishers: What You Need to Know
In the face of a fire emergency, having the right knowledge and tools at hand can be the difference between a minor incident and a catastrophic event. Handheld fire extinguishers are indispensable firefighting devices that play a crucial role in safeguarding lives and property.
The specific class of fire and environment dictates the type of handheld device that is required and what kind of extinguishing agent should be used. Understanding the different types of fire extinguishers and their respective uses is important whether it is for a home, business, school, etc.
Classes of Fire Extinguishers
Class A fire extinguishers are used for fires involving standard combustible materials such as wood, paper, cloth, plastics, and rubber. Depending on the specific type of extinguisher, it may use high pressure water, foam, or dry chemical agents to smother and cool the flames. Class A fire extinguishers are the most common solution for safety use in standard home, office, and school environments.
Class B fire extinguishers are designed for extinguishing flammable liquid fires, including gasoline, oil, grease, and solvents. These are commonly filled with dry chemical agents like carbon dioxide (CO2), dry powder, or foam to suffocate the fire and prevent re-ignition.
Class C fire extinguishers are primarily used to combat electrical fires, where the source of the fire involves live electrical equipment. Because of the electrical nature of the fire, the extinguishers contain non-conductive extinguishing agents—such as CO2 or dry chemical powder—to extinguish the flames without conducting electricity.
Class D fire extinguishers are tailored for fires fueled by combustible metals, such as magnesium, titanium, potassium, and sodium. To combat this, the fire extinguishers are loaded with specialized dry powder agents designed to absorb heat and smother the fire.
Class K fire extinguishers are specially designed for fires that involve cooking oils, grease, and fats typically found in kitchens. Restaurants and other buildings such as a school, nursing home, or retail space are examples of locations that might require Class K fire extinguishers. To put out these fires, the extinguishers contain liquid agents like potassium acetate or potassium citrate to quickly convert and cool down the burning oils. It is important to note that using a Class A water-based extinguisher on oils and grease can make the situation worse.
Multi-Class (ABC) fire extinguishers are the most versatile as they combine Class A, B, and C capabilities, making them suitable for a variety of fire situations. They are likely to be equipped with dry chemical agents, like monoammonium phosphate or ammonium sulfate, to tackle different fire classes effectively.
Types of Fire Extinguishers
Now we dive into a comprehensive but not exhaustive list of the common types of fire extinguishers. When choosing the right extinguisher, fire system companies will do an evaluation of your home, building, or retail establishment to determine that you are receiving the right type of fire extinguisher for your situation.
PRESSURIZED WATER MODELS. These are your recognizable red extinguishers with a white symbol and appropriate for use on Class A fires only. These are used for common wood, paper, and fabric fires and must never be used on electrical or flammable-liquid fires.
CARBON DIOXIDE. These extinguishers contain pressurized liquid carbon dioxide, which turns to a gas when expelled. These models are rated for use on Class B and C fires (flammable liquids and electrical fires) but can be used on a Class A fire. Carbon dioxide displaces oxygen and does not leave residue.
DRY CHEMICAL. These versatile extinguishers are either stored-pressure models or cartridge-operated models and are suitable for Class A, B, and C fires. They are characterized by a white or pale-yellow color and prominently marked with symbols representing multiple fire classes. The extinguisher contains a dry chemical powder, typically monoammonium phosphate or ammonium sulfate, which forms a barrier over the fuel, suppressing the flames and preventing re-ignition.
AMMONIUM PHOSPHATE. The dry chemical in this extinguisher can be used on Class A, B, and C fires, but should never be used on a fire in a commercial grease fryer because of the possibility of reflash and because it will render the fryer's automatic fire-protection system less effective.
SODIUM BICARBONATE. This is a dry chemical extinguisher, suitable for fighting Class B and C fires. It is preferred over other dry-chemical extinguishers for fighting grease fires. Where provided, always use the extinguishing system first. This also shuts off the heat to the appliance.
POTASSIUM BICARBONATE, UREA-BASE POTASSIUM BICARBONATE, & POTASSIUM CHLORIDE. These are dry chemical extinguishers that are more effective and use less agent than sodium bicarbonate on the same fire.
FOAM (or AFFF & FFFP) EXTINGUISHERS - coat the surface of a burning flammable liquid with a chemical foam. When using a foam extinguisher, blanket the entire surface of the liquid to exclude the air.
What Type of Fire Extinguisher Should You Choose?
Selecting the appropriate fire extinguisher based on the type of fire is vital in extinguishing the flammable materials safely and efficiently. Delta Fire team members can recommend the best fire extinguisher given your specific situation and environment. We are also available for regular maintenance, testing, and training in their proper use. We can help determine where to place fire extinguishers for easy accessibility, help you understand their operation, and do an assessment of the property to uncover potential fire hazards.
