A Comprehensive Guide to Fire Extinguisher Types and Their Uses

A Comprehensive Guide to Fire Extinguisher Types and Their Uses

Every year, fire causes billions of dollars in property damage and thousands of injuries — many of which could be prevented or minimized by having the right fire extinguisher on hand. Fire is one of the leading causes of loss in almost every industry, so it's important to not only have fire safety equipment on hand, but to understand what fire extinguisher is used for what situation. Fire extinguishers play a critical role in safety, serving as the first line of defense in stopping small fires before they become devastating. However, not all fires are the same. Classified into types such as Class A, B, C, D, and K based on the materials involved, each fire requires a specific kind of extinguisher to be handled effectively.

In this article, SkyGeek dives deep into the essentials of fire safety, with a guide to fire extinguisher types their recommended uses and how effective they are at extinguishing various classes of fire. By the end of the article, you’ll have the knowledge you need to respond quickly and confidently in a fire-related emergency. 

Understanding Fire Classes

To effectively fight a fire, you need to understand what kind of fire you're dealing with. Fires are divided into five classes, based on the materials involved. Each class of fire requires a specific type of fire extinguisher for safe and effective suppression.

• Class A – Ordinary Combustibles
  Fires involving common materials such as wood, paper and fabric. These are the most common types of fires in homes and offices. Knowing how to extinguish Class A fire is essential for residential and commercial safety.
• Class B – Flammable Liquids
  This class includes fires fueled by gasoline, oil, paint, solvents and other flammable or combustible liquids. Common in workshops, garages, hangars and industrial settings. It’s important to understand what type of fire extinguisher for flammable liquids to use in these environments.
• Class C – Electrical Equipment
  Fires caused by energized electrical equipment such as wiring, circuit breakers, appliances and machinery. These require non-conductive extinguishing agents.
• Class D – Combustible Metals
  Fires involving metals like magnesium, titanium and aluminum, typically found in manufacturing or laboratory environments. These fires require specialized extinguishers.

• Class K (or F) – Cooking Oils and Fats
  Fires that originate from cooking products like vegetable oils, grease or lard. These type of fires are common in commercial kitchens. They burn hotter than others and need a wet chemical extinguisher. 

Types of Fire Extinguishers and Their Mechanisms

Choosing the right fire extinguisher starts with understanding different types of extinguishers and how each works against specific fire extinguisher classes. Here's a breakdown of the most common types of fire extinguishers, how they work and what they work on:

• Water Extinguishers
  These extinguishers work by cooling the burning material, thus reducing the temperature below ignition point. They are best as a Class A fire extinguisher used for Class A (ordinary combustibles) fires. Do not use water extinguishers on Class B (flammable liquids) or Class C (electrical) fires, as they can spread the flames or pose an electrocution risk.
  
• Foam Extinguishers (AFFF & FFFP)
  Foam extinguishers suppress fire by smothering it. They cut off oxygen, which is required for combustion, then cool the underlying They are suitable for both Class A and Class B fires, AFFF (Aqueous Film Forming Foam) is commonly used for flammable liquids, while FFFP (Film-Forming Fluoroprotein) is preferred in environments like airports or industrial sites for added fuel resistance. 
• Dry Chemical Extinguishers (ABC, BC, D)
  These extinguishers work by interrupting the chemical reaction at the fire's core.
   
  • ABC extinguishers use monoammonium phosphate and are effective on Class A, B, and C fires, making them highly versatile.
  • BC extinguishers use sodium bicarbonate or potassium bicarbonate, targeting Class B and C fires.
  • Class D extinguishers contain special dry powders to suppress metal fires like magnesium or titanium by absorbing heat and smothering flames.
• Carbon Dioxide (CO₂) Extinguishers
  Carbon dioxide extinguishers work by displacing oxygen, which effectively suffocates the fire. Best for Class B and C fires, they leave no residue behind, making them ideal for use around sensitive equipment. However, they have limited range and can pose an asphyxiation risk to the operator in
• Wet Chemical Extinguishers
  These are designed specifically for Class K (or F) fires involving cooking oils and fats. The extinguishers work through saponification, which is a chemical reaction that occurs when a fat or oil reacts with an alkali to form soap and water. It cools the fire and forms a soapy barrier to prevent it from reigniting. These extinguishers are essential in commercial kitchen environments.
• Clean Agent Extinguishers (Halotron, FM-200)
  These extinguishers suppress fires by interfering with the chemical reaction, while also being non-conductive and residue-free. Suitable for Class A, B, and C fires, they’re especially useful in environments with sensitive electronics like data centers, labs and avionics.

• Dry Powder Extinguishers
  These specialized extinguishers are used exclusively on Class D fires involving combustible metals. The type of dry powder must be matched to the specific metal to ensure safe and effective suppression. Using the wrong agent can worsen the fire or cause dangerous reactions. 

Fire Extinguishers by Class

Fire extinguishers are commonly grouped into fire extinguisher classes based on the types of fires they’re designed to combat, ensuring effective and safe fire suppression. This simple lettering system helps reduce accidents and shorten response times. Understanding these classes — A, B, C, D, and K — helps you choose the right extinguisher for the specific hazards in your environment. 

• Class A Fire Extinguishers:
  Class A fire extinguishers are designed to put out fires that involve ordinary combustibles such as wood, paper, cloth and plastics. Class A fire extinguishers are typically kept in residential spaces because they work on the most common type of fires that occur in homes and offices. Class A fire extinguishers work by cooling the fire and removing heat from the fuel source, thereby extinguishing the flames.
• Class B Fire Extinguishers:
  Class B fire extinguishers are used to put out fires that involve flammable liquids such as gasoline, oil or grease. These types of fires are common in garages and workshops where these liquids are frequently used. Automotive repair shops, aircraft hangars and similar businesses often have a Class B fire extinguisher available in the event of a fire emergency. Class B extinguishers work by smothering the fire and preventing oxygen from reaching the fuel source, thereby extinguishing the flames.
• Class C Fire Extinguishers:
  Class C fire extinguishers are used to put out fires that involve electrical equipment such as appliances, computers and wiring. These types of fires can be very dangerous as the electrical current can be conducted through the water or foam used in a standard fire extinguisher, putting the person attempting to extinguish the fire at risk of electrocution. Class C fire extinguishers are often kept in places like server rooms, where the risk of electrical fires is high. Class C extinguishers work by using non-conductive agents to extinguish the fire, such as carbon dioxide or dry chemical powder.
• Class D Fire Extinguishers:
  Class D fire extinguishers are used to put out fires that involve flammable metals such as magnesium, titanium and sodium. These types of fires are rare, but they can be extremely dangerous and require specialized extinguishers to combat them. Certain types of laboratories may need to have this type of fire extinguisher on hand. Class D extinguishers work similarly to other fire extinguishers, by smothering the fire and preventing oxygen from reaching the fuel source. However, they use an extinguishing agent that will not react with flammable metals.

Extinguisher Type	Suitable Fire Classes	Common Environments
Water	A	Homes, offices
Foam (AFFF, FFFP)	A, B	Warehouses, garages, light industrial
Dry Chemical (ABC)	A, B, C	Homes, offices, workshops, vehicles
Dry Chemical (BC)	B, C	Industrial, fuel storage areas
Dry Powder (Class D)	D	Laboratories, metalworking facilities
CO₂	B, C	Offices, server rooms, electronics
Wet Chemical	K/F	Commercial kitchens, restaurants
Clean Agent (Halotron/FM-200)	A, B, C	Data centers, aircraft, sensitive equipment

Class K Fire Extinguishers:
Class K fire extinguishers are used to put out fires that involve cooking oils, grease and fats. These types of fires are common in commercial kitchens and can be extremely dangerous if not dealt with quickly and effectively. Water can cause a grease fire to spread quickly, so these types of fire emergencies require a fire extinguisher the does not use water as the extinguishing agent. Class K extinguishers work by using a wet chemical agent that reacts with the oil or fat to form a soap-like substance, thereby extinguishing the fire.

Choosing the Right Fire Extinguisher

Selecting the right fire extinguisher starts with assessing the specific fire hazards present. For example, class a fire extinguisher is common in homes and offices, while industrial settings may require extinguishers for Class B, D or specialized hazards. Kitchens, especially commercial ones, are prone to Class K fires involving cooking oils. Vehicles and aircraft require compact, residue-free extinguishers that can tackle electrical or fuel fires. When choosing an extinguisher, consider not just the type of fire, but also the likely fire size, ease of access and the training level of potential users. Matching the extinguisher type to the highest fire risk in that environment ensures a safer, more effective fire response.

Proper Use of a Fire Extinguisher (PASS Method)

Knowing how to use a fire extinguisher correctly can make all the difference in an emergency. The P.A.S.S. method is a simple, easy-to-remember technique that guides users through the process of deploying a fire extinguisher:

• Pull the pin to unlock the extinguisher.
• Aim the nozzle or hose at the base of the fire, where the flames are coming from.
• Squeeze the handle slowly and evenly to release the extinguishing agent.
• Sweep the nozzle from side to side, covering the entire area of the fire until it’s fully out. 

Remember to stand a safe distance from the fire and move closer as it is put out.

Need a demonstration? Watch a firefighter show how to use a fire extinguisher.

Maintenance and Inspection

Regular inspection and maintenance of your fire extinguishers ensure that they’ll work correctly when needed. Inspections should include verifying that the pressure gauge needle is in the green zone, the tamper seal is intact and there is no visible physical damage like dents or corrosion. In commercial settings, it is particularly important to schedule professional servicing annually or as recommended by the manufacturer to replace expired extinguishing agents and conduct thorough internal inspections. Keeping your extinguishers in top condition helps maintain safety and compliance with local fire regulations.

Conclusion:

Fire safety is critically important, and having the right type of fire extinguisher for the situation can make all the difference in protecting yourself, your property, and those around you. Different extinguishers are designed to tackle specific classes of fires — Class A for ordinary combustibles, Class B for flammable liquids, Class C for electrical fires and multipurpose extinguishers that cover several types. Understanding these distinctions helps ensure you respond effectively in an emergency, preventing a small fire from becoming a major disaster.

To stay prepared, make sure your home or workplace is equipped with the appropriate fire extinguishers and that they're readily available. It’s also important to educate everyone in your family or company on where the fire extinguishers are located and how to use them correctly. Take a moment to review your fire safety plans today and confirm you have the proper extinguishers for potential fire hazards. Make sure that everyone knows how to operate them confidently and double-check that your fire extinguishers are not expired. Being proactive can save lives and minimize damage when it matters most.