Fire safety is a top priority for any home or business. A key part of being prepared is understanding how to prevent fires and how to respond if one starts. Knowing about the different types of fire extinguishers is essential in this process. Portable fire extinguishers are vital tools, and they come in several varieties, including water, carbon dioxide, dry chemical, and wet chemical extinguishers.
These devices are not one-size-fits-all. Fire extinguishers vary in how well they work against different types of fire, such as those involving ordinary combustibles like wood, flammable liquids, or electrical equipment. It’s crucial to have a fire extinguisher in easy-to-reach places, like kitchens and garages, so you can act fast. The fire department recommends having an extinguisher on each level of a building and in areas where fires are more likely to occur. This guide will help you understand the different types of fire extinguishers and choose the right one for your needs.
The Fire Triangle: How Fire Extinguishers Work
To fight a fire effectively, it helps to know what makes it burn. The fire triangle is a simple way to understand this. It shows that a fire needs three things to start and keep burning:
- Oxygen: Air provides the oxygen.
- Heat: This is the ignition source that raises the material to its ignition temperature.
- Fuel: This is any burnable material, like wood, gasoline, or paper.
If you remove any one of these elements, you can put out the fire. This is how fire extinguishers work, by cooling the fuel, cutting off oxygen, or creating a barrier between the fuel and oxygen.
The Different Classes of Fire
Just as there are different ways to put out a fire, there are also different types of fire. These are grouped into classes. There are five main classes of fire:
| Fire Class | Materials Involved |
| Class A | Ordinary combustibles: wood, paper, cloth, rubber, plastics |
| Class B | Flammable liquids: gasoline, greases, tars, oil-based paints, solvents, lacquers, flammable gases |
| Class C | Energized electrical equipment: appliances, wiring, circuit breakers, outlets |
| Class D | Combustible metals: magnesium, titanium, zirconium, sodium, lithium, potassium |
| Class K | Cooking oils and fats in commercial cooking appliances, vegetable oils, animal oils |
Knowing these different types of fire and what fuels them is the first step in choosing the correct extinguisher.
Fire Extinguisher Types and Characteristics
There are several types of fire extinguishers, each designed to tackle specific classes of fires. The extinguishing agent inside the canister is what makes it effective against certain fire types. Here’s a quick overview:
| Extinguisher Type | What It’s For (Primary Use) |
|---|---|
| Water | Class A fires (wood, paper, cloth) |
| Carbon Dioxide (CO2) | Class B (flammable liquids) and Class C (electrical) fires |
| Dry Chemical (ABC) | Class A, Class B, and Class C fires (multipurpose) |
| Dry Chemical (BC) | Class B and Class C fires |
| Wet Chemical | Class K fires (cooking oils and fats in kitchens) |
| Class D (Dry Powder) | Class D fires (combustible metals) |
Let’s look a little closer at these common fire extinguisher types:
1. Water Extinguishers
These extinguishers are good for Class A fires. Class A fires happen when things like wood, paper, or cloth catch fire. Water extinguishers work mostly by cooling whatever is burning. This makes the burning material cooler than the temperature it needs to keep burning. The water also soaks the material, which helps stop the fire too.
Very Important: Never use water extinguishers on fires with flammable liquids like gasoline or oil (these are Class B fires). Also, don’t use them on fires with electrical stuff that’s plugged in (Class C fires), because you could get shocked. And don’t use them on cooking oil fires (Class K fires), because water can make those fires spread and get much worse.
2. Carbon Dioxide (CO2) Extinguishers
Carbon Dioxide (CO2) extinguishers work well on Class B fires (flammable liquids and gases) and Class C fires (electrical equipment that’s turned on). CO2 is a gas that doesn’t burn. When you spray it, it pushes away the oxygen that the fire needs to burn. This is called smothering the fire.
The CO2 also comes out very cold, which helps cool the fire down. A big plus for CO2 extinguishers is that they don’t leave any messy stuff behind. This makes them a good choice for putting out fires on sensitive electrical equipment or in places where cleaning up would be hard.
3. Dry Chemical Extinguishers
Dry chemical extinguishers are very common. They use a powder to fight fires and come in a couple of types.
ABC Dry Chemical
These are called multipurpose extinguishers because they can be used on Class A, B, and C fires. That means they work on ordinary burning things, flammable liquids and gases, and electrical fires. The powder in them stops the chemical reaction of the fire. It also makes a wall between the oxygen and the fuel (the thing that’s burning).
BC Dry Chemical
These are good for Class B (flammable liquids and gases) and Class C fires (electrical). Dry chemical extinguishers leave behind a powder that you’ll need to clean up.
4. Wet Chemical Extinguishers
These extinguishers are made just for Class K fires. These are fires that involve cooking stuff like vegetable oils and animal fats, often found in restaurant kitchens. The special liquid inside, usually something like potassium acetate, does two things.
First, it cools the fire down. Second, it reacts with the hot oil to make a soapy foam blanket on top. This blanket stops the fire from starting up again. These are the extinguishers you’ll usually see in commercial kitchens.
5. Class D Extinguishers
Class D extinguishers use a special dry powder. This powder is made only for fires that involve combustible metals. These are metals that can burn, like magnesium, titanium, or sodium.
The powder smothers the fire and also pulls heat away from it. You can’t use these on other kinds of fires. Also, you need to make sure you’re using the right kind of Class D powder for the specific metal that’s burning, because using the wrong one can be dangerous.
Beyond the type of extinguishing agent, fire extinguishers vary in their size, weight, and discharge time. It’s important to choose one that is appropriate for the potential fire hazard and can be handled by those who might need to use it.
How to Choose the Right Fire Extinguisher
Choosing the right fire extinguisher depends on several factors:
- What might catch fire? In a kitchen, you might have oil fires (Class K) or paper fires (Class A). Garages could have gasoline fires (Class B) or electrical fires (Class C). Living rooms often have furniture fires (Class A).
- How big is the space? Bigger spaces might need bigger or more extinguishers. The label will tell you how much area it covers.
- Can you reach it easily? Keep the extinguisher where you can get to it quickly. Don’t hide it behind stuff.
- Does it match the fire type? Most homes use A-B-C extinguishers, good for many fires. But kitchens with fryers need a Class K extinguisher.
- Is it safety-checked? Make sure the extinguisher is approved by labs like UL or FM. This means it’s safe and works well.
Think about the most common materials in each part of your home or business. For example, an office might need protection against Class A (paper, wood) and Class C (computers, electronics) fires. A workshop with oil based paints and solvents would need a Class B extinguisher.
How to Use a Fire Extinguisher Correctly
Having the right extinguisher is only half the battle; you also need to know how to use it. Proper training is highly recommended. The fire department often provides resources or can point you to training opportunities. Most portable fire extinguishers are operated using the P.A.S.S. method:
- PULL the pin. This pin is usually held in place by a tamper seal. Breaking the seal and pulling the pin will allow you to discharge the extinguisher.
- AIM the nozzle or hose at the base of the fire. Hitting the flames higher up won’t be as effective. You need to target the fuel.
- SQUEEZE the handle or lever slowly and evenly. This releases the extinguishing agent. Releasing the handle will stop the discharge.
- SWEEP the nozzle from side to side, covering the base of the fire until it appears to be out. Watch for re-ignition and be prepared to apply more agent if needed.
Important Safety Tips:
- Always make sure you have a clear escape route before attempting to fight a fire.
- Stand at a safe distance from the fire, typically 6-8 feet away, as recommended on the extinguisher label.
- If the fire is too large, spreading quickly, or if you don’t feel comfortable using the extinguisher, evacuate the area immediately and call the fire department.
- The fire department recommends practicing with an extinguisher (perhaps an old or expired one under supervision) to build confidence and proficiency.
Stay Safe and Prepared
Understanding the different fire extinguisher types and how to choose, use, and maintain them is a critical part of overall fire safety. By identifying the potential fire hazards in your environment and ensuring you have the correct, well-maintained extinguisher readily available, you can significantly improve your ability to respond to a small fire before it becomes a major disaster.
If you have questions about your fire safety needs or need professional advice on selecting and installing fire extinguishers, we’re here to help. Contact B&W Fire Security Systems today for a consultation and ensure your property is properly protected. Contact Us
Frequently Asked Questions
What are the 5 main types of fire extinguishers?
The five main types are Water (for Class A fires like wood and paper), Carbon Dioxide (for Class B flammable liquids and Class C electrical fires), Dry Chemical (multipurpose for Class A, B, C, or specific for B, C), Wet Chemical (for Class K cooking oil fires), and Class D (for combustible metal fires). Each type uses a different agent to fight specific fire classes.
What kind of fire is a Class A fire?
Class A fires involve ordinary combustible materials such as wood, paper, cloth, rubber, and many plastics. Water extinguishers are suitable for these types of fires because they cool the burning material.
Which fire extinguisher is generally recommended for home use?
For general home use, multipurpose ABC dry chemical extinguishers are popular because they are effective against Class A fires (wood, paper), Class B fires (flammable liquids), and Class C fires (energized electrical equipment). Always assess specific risks in areas like kitchens or garages.
How do you use a fire extinguisher correctly?
Remember the P.A.S.S. method: Pull the pin, Aim the nozzle at the base of the fire, Squeeze the handle slowly and evenly, and Sweep the nozzle from side to side. Ensure you have a clear escape route before attempting to fight a fire.
How often do I need to inspect my fire extinguisher?
You should perform a visual check monthly for obvious damage, ensure the pressure gauge is in the green, and verify it’s accessible. Additionally, fire extinguishers should be inspected every year by a certified professional. For more details, see our annual fire extinguisher inspection checklist.
What fire extinguisher should I use for a kitchen fire involving cooking oil?
For fires involving cooking oils and fats, like those in deep fryers, a Class K extinguisher containing a wet chemical agent is specifically designed. These are essential in commercial kitchens and very effective for these dangerous fires.
When should I not try to fight a fire with an extinguisher?
You should not attempt to fight a fire with an extinguisher if the fire is too large, spreading quickly, if you don’t have a clear escape route, or if you are uncomfortable or untrained. In these situations, your priority is to evacuate everyone safely and call the fire department immediately.
