Fire safety is a critical component of workplace health and safety. Whilst this is particularly true of environments where the risk of fire is present – such as businesses and industries that use flammable chemicals or materials, naked flames, heavy machinery, heated equipment, and so on – fires can happen in almost any location. Knowing how to respond effectively to a fire starts with understanding the different classes of fire and fire extinguishers, as each type of fire requires a specific kind of extinguisher to ensure proper control and extinguishment.

In this blog, we’ll explore the various fire classes and extinguishers to help businesses and individuals stay prepared in the event of a fire. We will also cover the different fire extinguisher types available and their specific uses to ensure safety in fire management.

What are the different classes of fire?

Fires are classified based on the type of material that fuels them. Each class of fire behaves differently and requires a specific type of extinguisher to manage. Here's a breakdown of the key fire classes:

Class A fire

A Class A fire is the most common type of fire and involves everyday combustible materials such as wood, paper, cloth, and plastics. These materials can be found in homes, offices, schools, and industrial environments. Class A fires typically burn with visible flames and are often started by careless acts like leaving lit candles unattended or improperly discarding cigarette butts.

To extinguish a Class A fire, water based extinguishers, such as water or foam extinguishers, are most effective. Water cools the fire and prevents it from spreading, while foam extinguishers smother the flames by cutting off the fire’s oxygen supply.

Class B fire

A Class B fire involves flammable liquids like gasoline, oil, grease, solvents, and alcohol. These fires are particularly dangerous because they can spread quickly and are challenging to contain. Unlike Class A fires, Class B fires cannot be extinguished using water, as this can cause the fire to spread further.

It is important to note that standard dry powder extinguishers should not be used for fires involving cooking oil. Using appropriate extinguishing methods is crucial for safety when handling different types of fires.

Fire extinguishers for Class B fires typically use foam, carbon dioxide (CO2), or powder. Foam extinguishers work by creating a barrier between the fuel and the air, while CO2 extinguishers displace the oxygen needed to sustain the fire. Powder extinguishers work by interrupting the chemical reaction of the fire.

Class C fire

A Class C fire is caused by flammable gases such as propane, butane, or methane. These gases are often stored under pressure and, if ignited, can lead to explosive fires. Due to the volatility of these gases, it is essential to use the right type of extinguisher to prevent further escalation.

For Class C fires, dry powder extinguishers are typically used. These extinguishers work by interrupting the chemical reaction in the fire, thereby preventing it from spreading. Never use water or foam extinguishers on gas fires, as they can worsen the situation.

Class D fire

Class D fires involve combustible metals such as magnesium, aluminium, potassium, and sodium. These metals burn at high temperatures and react violently with water, making them particularly dangerous in industrial and laboratory settings.

To tackle a Class D fire, a specialist powder extinguisher is required. These extinguishers contain a dry powder that absorbs the heat and smothers the fire by creating a barrier between the metal and oxygen.

Electrical (Class E) fires

Electrical fires are not strictly classed a separate fire class (Class E), because electricity is more of a source of ignition than a fuel. However, electrical fires are common in environments with faulty wiring, overloaded circuits, or damaged electrical appliances. These fires can start in offices, factories, or homes, and they require a specific type of extinguisher for electrical equipment.

CO2 and dry powder extinguishers are the most effective for electrical fires involving electrical equipment. CO2 extinguishers work by displacing the oxygen around the fire, while dry powder extinguishers interrupt the fire’s chemical reaction. Water and foam extinguishers should never be used on electrical fires, as they conduct electricity and pose the risk of electric shock.

Class F fire

A Class F fire involves cooking oils and fats, typically found in commercial kitchens or deep fryers. Class F fires are particularly dangerous due to the high temperatures involved and the risk of splattering oil.

Wet chemical extinguishers are the most effective for Class F fires. These extinguishers work by creating a chemical reaction that cools the flames and forms a barrier between the oil and the air, preventing reignition.

Fire extinguisher class types

Now that we’ve covered the different classes of fires, it’s essential to understand the types of fire extinguisher available and their specific uses, as well as which class of fire each one can be used for.

The main fire extinguisher class types include:

1. Water extinguishers

Water extinguishers are ideal for Class A fires involving combustible materials like wood and paper. They work by cooling the flames and are easily recognisable by their red label.

2. Foam extinguishers

Foam extinguishers are suitable for both Class A and B fires. They create a barrier between the fuel and the air, smothering the fire. These extinguishers are marked with a cream label.

3. Carbon dioxide (CO2) extinguishers

CO2 extinguishers are used for Class B fires and electrical fires. They displace the oxygen around the fire, cutting off its oxygen supply. CO2 extinguishers are easily identified by their black label.

4. Dry powder extinguishers

Powder fire extinguishers can be used on Class A, B, and C fires, making them highly versatile tools for combating various types of fires. However, they can create a mess and are less effective for Class F (cooking oil) fires. These extinguishers have a blue label.

5. Wet chemical extinguishers

Wet chemical extinguishers are specifically designed for Class F fires. These extinguishers cool the fire and form a barrier to prevent the fire from reigniting. They are marked with a yellow label.

Why understanding fire classes and extinguishers matters

Understanding classes of fire and fire extinguishers is crucial for ensuring safety in workplaces, homes, and public spaces. Using the wrong fire extinguisher for a specific class of fire can be dangerous and may exacerbate the fire. For example, using water on a Class B or electrical fire can spread the flames or lead to electric shock.

Businesses and industries must ensure they have the right type of fire extinguisher for the risks present in their environment. Regular fire safety training is also essential to ensure that employees understand about fire classes and extinguishers, know which extinguisher to use, and how to operate it correctly in the event of a fire.

By investing in the right fire extinguishers, PPE, and safety protocols, businesses can reduce fire risks and ensure a safer working environment for everyone.

How phs Besafe can help

phs BeSafe is committed to supporting businesses and industries where fire is a risk by providing high quality protective wear and fire safety solutions. Whether you work in an industrial setting with metalworking or in a commercial kitchen with high temperatures, phs BeSafe offers a range of personal protective equipment (PPE) to keep employees safe from fire related hazards.

For more information on how phs BeSafe can support your business with fire safety solutions and PPE, give us a call today.