Not all fires follow the same rules. Use the wrong extinguisher and you can make a bad situation worse. Knowing what kind of fire you are dealing with and how to respond is not optional. It is essential. The right knowledge and equipment can help you control a fire when it is safe to do so. But not every fire should be fought. Life safety always comes first.
Let us walk through the major fire classes. I will show you what causes them, what you should and should not do, and where you are likely to see them.
Class A – Ordinary Combustibles
The most common fires. The easiest to control if you use the right method.
What it is:
Fires that involve everyday materials such as paper, wood, fabric, cardboard, and trash.
How to handle it:
Use a water-based or multipurpose ABC extinguisher. Water cools the burning materials and helps prevent reignition.
Where you will see it:
Offices, warehouses, schools, homes.
Class B – Flammable Liquids and Gases
Water makes these fires spread. Smother them, do not spray them.
What it is:
Fires involving flammable liquids such as gasoline, oil, alcohol, paint, and propane.
How to handle it:
Never use water. Use a foam, CO2, or dry chemical extinguisher. These cut off the oxygen supply and smother the fire.
Where you will see it:
Fuel storage areas, garages, workshops, gas stations.
Class C – Electrical Equipment
Electricity and water never mix. Use CO2 or dry chemical.
What it is:
Fires involving energized electrical equipment. Think wiring, outlets, circuit breakers, appliances, or machinery.
How to handle it:
Do not use water. Use a CO2 or dry chemical extinguisher that is rated for electrical fires. Once power is shut off, the fire may become Class A or B, depending on the materials burning.
Where you will see it:
Server rooms, control panels, electrical closets, places where power tools or appliances are used.
Class D – Combustible Metals
Rare, extremely dangerous, and requires special handling.
What it is:
Fires involving combustible metals such as magnesium, titanium, sodium, lithium, and potassium.
How to handle it:
Use a Class D dry powder extinguisher only. Water or foam can cause violent reactions. This is specialized equipment, and you must know where it is and when to use it.
Where you will see it:
Metalworking facilities, chemical labs, industrial manufacturing plants.
Class K – Cooking Oils and Fats
Grease fires explode when water is used. Use wet chemical extinguishers only.
What it is:
Fires caused by high temperature cooking oils and grease. Common in deep fryers and commercial kitchens.
How to handle it:
Use a Class K wet chemical extinguisher. It creates a soapy layer that cools and smothers the fire. Never use water, as it will cause grease fires to explode.
Where you will see it:
Restaurants, food trucks, commercial kitchens, cafeterias.
A Word About Water
Water is effective for Class A fires only. If you use it on Class B, C, D, or K fires, you will make the situation worse. Using the wrong extinguisher does not guarantee success and can increase the danger. Not every fire can or should be controlled with portable equipment.
The Right Approach
Here is what you and your team should do:
Know your environment. Place the right extinguishers in the right locations.
Train your team. Everyone should know PASS. Pull, Aim, Squeeze, Sweep.
Inspect your equipment. Extinguishers do not check themselves. You must inspect them regularly.
When in doubt, get out. Portable extinguishers are meant for small fires. If the fire grows, evacuate immediately and call emergency services.
Final Word
Fire safety is about preparation, not reaction. The right extinguisher, used at the right time, can help control a fire. But your priority must always be life safety.
If you are not sure your site is properly protected, let us help. We will walk your space and show you where you stand. The first step to prevention is knowing where you are today.