Fire extinguishers are one of the most recognizable pieces of fire protection equipment in a building — but not every extinguisher is designed for the same kind of fire.

For business owners, facility managers, property managers, and safety teams, understanding the basics can help you make smarter decisions about extinguisher placement, employee readiness, and ongoing compliance. The right extinguisher, in the right location, can support a safer first response during an incipient-stage fire. The wrong extinguisher, or one that is blocked, missing, or improperly maintained, can create unnecessary risk.

Below, we’ll break down the most common types of fire extinguishers, what the different fire extinguisher classes mean, where you might find them in a commercial facility, and when training comes into the picture.

Why fire extinguisher type matters

Fire extinguishers are selected based on the types of fire hazards present in a space. A commercial kitchen, an office area, a manufacturing floor, and an electrical room may all require different extinguisher considerations.

That is because fires are classified by the materials or fuel sources involved. Some extinguishers are designed for ordinary combustibles like paper and wood, while others are intended for flammable liquids, energized electrical equipment, combustible metals, or cooking oils and fats.

Using the wrong type of extinguisher can be ineffective — and in some cases, dangerous. For example, a standard water extinguisher should not be used on an energized electrical fire or a grease fire. That is why extinguisher selection, placement, inspection, and employee training should all work together as part of your broader fire protection plan.

Common types of fire extinguishers

Here are several common types of portable fire extinguishers you may see in commercial and industrial buildings.

Water and water mist extinguishers

Water extinguishers are generally used for ordinary combustible materials such as paper, wood, cloth, and some plastics. Water mist extinguishers use a fine spray and may be used in certain environments where a traditional water stream is not ideal.

You may see these in office areas, schools, common spaces, or other locations where ordinary combustible materials are the main concern.

Foam extinguishers

Foam extinguishers are often used for fires involving ordinary combustibles and certain flammable liquids. The foam helps blanket the fuel source and reduce the oxygen feeding the fire.

These may be found in areas where flammable liquids are present, depending on the specific hazard and extinguisher rating.

Dry chemical extinguishers

Dry chemical extinguishers are among the most common extinguishers in commercial buildings. Many are labeled as ABC extinguishers, which means they can be used on Class A, Class B, and Class C fires.

These are frequently found in offices, warehouses, retail spaces, schools, healthcare facilities, and general commercial environments.

Carbon dioxide / CO₂ extinguishers

CO₂ extinguishers are commonly used around energized electrical equipment because they do not leave behind the same residue as a dry chemical extinguisher. They work by displacing oxygen and interrupting the fire triangle.

You may find CO₂ extinguishers in server rooms, electrical rooms, laboratories, or areas with sensitive equipment. However, they may not be the best fit for every hazard, especially where cooling is needed after discharge.

Wet chemical extinguishers

Wet chemical extinguishers are designed for fires involving cooking oils and fats. These are most often associated with Class K fires.

You will commonly find them in commercial kitchens, restaurants, cafeterias, food service areas, and other facilities with deep fryers, grills, or similar cooking equipment.

Dry powder extinguishers

Dry powder extinguishers are specialized extinguishers used for combustible metal fires, also known as Class D fires.

These are not typically found in everyday office settings. They are more common in certain industrial, manufacturing, laboratory, machining, or metalworking environments where combustible metal shavings, powders, or dusts may be present.

Fire extinguisher classifications explained

Fire extinguishers are labeled by class to show what types of fires they are designed to fight.

Class A fire extinguishers

Used for: Ordinary combustibles
Examples: Wood, paper, cardboard, cloth, trash, and some plastics
Common locations: Offices, classrooms, hallways, storage rooms, and general building areas

A simple way to remember Class A is: A = Ash.

Class B fire extinguishers

Used for: Flammable liquids
Examples: Gasoline, oils, solvents, paints, and certain chemicals
Common locations: Warehouses, maintenance areas, garages, labs, mechanical spaces, and manufacturing facilities

A simple way to remember Class B is: B = Barrel, as in a barrel of flammable liquid.

Class C fire extinguishers

Used for: Energized electrical equipment
Examples: Electrical panels, wiring, computers, appliances, machinery, and other energized equipment
Common locations: Electrical rooms, server rooms, mechanical rooms, offices, and areas with powered equipment

A simple way to remember Class C is: C = Current.

Class D fire extinguishers

Used for: Combustible metals
Examples: Magnesium, titanium, sodium, potassium, and certain metal powders or shavings
Common locations: Metalworking, manufacturing, machining, laboratory, or specialty industrial environments

Class D extinguishers are highly specialized and should be selected based on the specific metal hazard present.

Class K fire extinguishers

Used for: Cooking oils and fats
Examples: Deep fryer oils, grease, and high-temperature cooking fats
Common locations: Commercial kitchens, restaurants, cafeterias, institutional kitchens, and food service areas

A simple way to remember Class K is: K = Kitchen.

Where fire extinguishers are commonly found in business facilities

Portable fire extinguishers should be easy to identify, accessible, and located based on the hazards in the building. OSHA notes that where portable fire extinguishers are provided for employee use, they must be mounted, located, and identified so they are readily accessible without subjecting employees to possible injury.

While exact placement depends on the building, occupancy, hazards, and applicable requirements, businesses often find extinguishers in areas such as:

• Hallways and exit routes
• Near exit doors
• Office areas and common spaces
• Break rooms and kitchenettes
• Commercial kitchens and food prep areas
• Mechanical and electrical rooms
• Warehouses and storage areas
• Loading docks
• Manufacturing or production areas
• Laboratories or specialty workspaces
• Company vehicles or mobile equipment, when applicable

The goal is not just to “have extinguishers.” The goal is to have the right type, in the right location, with clear visibility and access.

If extinguishers are hidden behind inventory, blocked by furniture, missing inspection tags, mounted incorrectly, or mismatched to the hazard, it may be time for a professional review.

Common business scenarios: which extinguisher might apply?

Every facility is different, but these examples show how extinguisher needs can vary by environment.

Office buildings

Office spaces usually include ordinary combustibles such as paper, cardboard, furniture, and trash, plus electrical equipment like computers, printers, and appliances. ABC dry chemical extinguishers are common in these environments.

Schools and childcare facilities

Schools often include classrooms, offices, cafeterias, mechanical rooms, and storage spaces. Extinguisher selection may vary by area, especially where kitchens, labs, or maintenance rooms are present.

Warehouses

Warehouses may include packaging materials, pallets, electrical equipment, forklifts, flammable liquids, and loading dock hazards. The extinguisher type and placement should reflect the specific materials stored and operations taking place.

Healthcare and assisted living facilities

Healthcare environments may include patient rooms, kitchens, laundry areas, mechanical rooms, electrical equipment, medical gases, and administrative spaces. These buildings often require careful documentation, maintenance, and staff readiness.

Restaurants and commercial kitchens

Commercial kitchens typically require special attention because of cooking oils, grease, and high-temperature equipment. Class K extinguishers are commonly found in these spaces, often alongside kitchen suppression systems.

Manufacturing and industrial facilities

Manufacturing environments can vary widely. Some may involve ordinary combustibles and electrical hazards, while others may include flammable liquids, combustible dust, or combustible metals. A site-specific assessment is especially important in these facilities.

OSHA training note for businesses

Fire extinguisher training is an important part of workplace safety planning. OSHA explains that employees who are designated to use fire extinguishers as part of an emergency action plan must be trained on how to use them appropriately, and that this training must be provided annually and when employees are first assigned those duties.

• OSHA training note: If employees are expected or designated to use fire extinguishers, employers must provide appropriate education and/or training under applicable OSHA workplace rules.

For more details and registration, visit FEI’s Fire Extinguisher Training Registration page.

When should a business call a fire protection professional?

A professional fire protection provider can help confirm that your extinguishers are appropriate for your facility, properly placed, inspected, tagged, and ready for use.

Consider scheduling a review if:

• You are not sure which extinguisher classes your facility needs
• Your building layout, occupancy, or operations have changed
• Extinguishers are blocked, damaged, missing, or hard to find
• Inspection tags are outdated or missing
• Your commercial kitchen, warehouse, lab, or industrial area has new hazards
• Employees need extinguisher training
• You are preparing for an inspection, audit, or insurance review

Fire extinguishers are a small but important part of a complete fire protection strategy. When they are selected, placed, maintained, and supported by proper training, they help businesses improve readiness and reduce risk.

Need help with fire extinguishers or employee training?

FEI supports businesses across New England with fire extinguisher service, inspection, maintenance, and training. Whether you need help identifying the right extinguisher types for your facility or registering your team for training, our team can help you take the next step.

Schedule Fire Extinguisher Service
Register for Fire Extinguisher Training

FAQ: Fire Extinguisher Basics for Businesses

What type of fire extinguisher is most common in businesses?

Many businesses use ABC dry chemical extinguishers because they are rated for Class A, B, and C fires. However, not every area of a building has the same hazards, so extinguisher selection should be based on the specific use of the space.

Where are fire extinguishers usually located in a commercial building?

Fire extinguishers are commonly found in hallways, near exits, office areas, kitchens, mechanical rooms, electrical rooms, warehouses, and other areas where fire hazards may exist. They should be visible, accessible, and appropriate for the hazard nearby.

Do employees need fire extinguisher training?

If employees are expected or designated to use portable fire extinguishers, OSHA requires appropriate education and/or training. Businesses should review their emergency action plan and employee responsibilities to determine what training applies.

How do I know if my business has the right extinguishers?

The best way is to have a qualified fire protection professional review your facility, hazards, extinguisher types, placement, inspection tags, and service history.