What are the classes of fire?
All fires are not made equal. Different classes of fire are governed by what
type of material the fire starts with. Understanding the type of fire that may
arise in your building is a prerequisite to finding the right fire extinguisher. You
will also need the right size and weight of fire extinguishers and put them in
the correct place.
Class A fires
Combustible materials, including flammable solids, such as wood, paper, and
textiles.
Class B fires
Flammable liquids, including petrol, paint, and spirits.
Class C fires
Flammable gases, including propane and butane.
Class D fires
Flammable metals, including chemicals such as magnesium, lithium, and
potassium.
Class E fires
Electrical equipment, including computers and photocopiers.
Class F fires
Cooking oils, including olive oil and butter.
What are the five main types of fire
extinguishers?
1. Water
2. Foam
3. Dry powder
4. CO2
5. Wet chemical
1. Water fire extinguishers for Class A fires
Standard water fire extinguishers can only be used on fires involving
flammable solids. However, they are still useful for most buildings, including
warehouses and storage facilities. They are available in 3, 6, and 9-litre sizes.
When the fire extinguishers are directed at flames, the water's extreme
cooling effect lowers the temperature of the material on fire, making it
impossible for the fire to burn.
Water fire extinguishers have a white-coloured label stating ‘Water’. They
should be identified by a nearby extinguisher ID sign fixed nearby stating
‘Water Extinguisher’.
What are water fire extinguishers used for?
Water fire extinguishers are ubiquitous as they are 'traditional fire
extinguishers'; however, current guidelines often recommend foam
extinguishers as they can extinguish both Class A and B fires.
Regardless, they are still useful for areas that contain a large amount of
combustible material, such as warehouses, storage units, paper mills, and
textile factories.
They are also helpful in domestic environments alongside CO2 extinguishers,
so the most likely fire types can be covered.
Do not use water fire extinguishers for:

Electrical fires as doing so can lead to electrocution

Cooking fires, such as chip pan fires (Class F fires)

Fires involving flammable gases, such as methane and butane (Class C
fires)

Fires involving flammable liquids, such as petrol and paint (Class B
fires)
2. Foam fire extinguishers
Foam extinguishers, also known as AFFF foam fire extinguishers, are
generally used for fires involving flammable solids and liquids. They are
available in 2, 3, 6, and 9-litre sizes—although 6 litre is the most common.
They can be identified with a cream–coloured label printed on the body stating
‘Foam’. Also, an ID sign should be placed near them stating ‘Foam
Extinguisher’.
Foam fire extinguishers work in two ways. First, they are water-based so they
lower the temperature of the fire. Second, they extinguish flames with their
aqueous film forming foam (AFFF), which smothers the fire, preventing it from
reigniting. The foam can be used on flammable liquids as it places a barrier
between the liquid and the flames.
Foam fire extinguishers are ideal for places with multiple fire risks, including
hotels, offices, garages, and factories. Most buildings can benefit from having
a foam fire extinguisher.
What are foam fire extinguishers used for?

Fires involving flammable solids, including paper, wood, and textiles
(Class A fires)

Fires involving some flammable liquids, including petrol, diesel, and
paint (Class B fires)
Do not use foam fire extinguishers for:

Cooking fires involving oil and grease (Class F fires)

Fires involving flammable gases (Class C fires)
3. Dry powder fire extinguishers
Dry powder fire extinguishers (also known as dry chemical fire extinguishers
and multi-purpose fire extinguishers) are incredibly versatile and can be used
for almost every kind of fire. However, they aren’t recommended for use in
enclosed spaces. The extinguishers come in 1, 2, 3, 6, and 9 kg sizes.
Dry powder fire extinguishers have a blue label stating powder, and they can
be identified by an ID tag saying Powder Extinguisher.
Dry powder fire extinguishers work by smothering fires; they place a barrier
between the source of oxygen and the fuel, so they can be used on most
types of fires. They suppress fires very quickly; however, they do not cool the
fire, so it could reignite. Specialist dry powder fire extinguishers work on
flammable metals.
Dry powder fire extinguishers are suitable indoors and outdoors as they can
be used with several different types of fire, including chemicals, fuel, or
vehicles.

Garage forecourts

Large, commercial boiler rooms

Flammable liquid storage facilities

Large workshops

Fuel tankers and other vehicles
What are dry powder fire extinguishers used for?

Fires involving flammable solids (Class A fires)

Fires involving flammable liquids (Class B fires)

Fires involving combustible gases (Class C fires)

Electrical fires involving some electrical items under 1000v
For electrical fires, it is also useful to have CO2 extinguishers, especially in
kitchens or if there are electric heaters around.

Specialist dry powder extinguishers work for flammable metals
Do not use dry powder fire extinguishers for:

Fires involving cooking oil (Class F fires)

Fires involving electrical items over 1000v

Fires in enclosed spaces
4.CO2 fire extinguishers
CO2 fire extinguishers (also known as carbon dioxide fire extinguishers) are
mainly used for electrical fires. Guidelines advise that they are paired with
foam extinguishers.
CO2 fire extinguishers can be identified by a black label saying CO2. They
have a distinctive black nozzle and should have an ID tag saying CO2
Extinguisher.
CO2 fire extinguishers discharge carbon dioxide, which is stored as a liquid
and converts to a gas when released. As the gas is released at speed, the fire
extinguishers should not be used with fires involving cooking oil as they may
spread the fire.
CO2 fire extinguishers do not cool fires; instead, they replace oxygen with
carbon dioxide, thus removing the fuel. For this reason, they are very effective
with electrical fires. CO2 fire extinguishers are particularly recommended for
places with a lot of electrical equipment, including offices, schools, and
hospitals, where they should be paired with foam extinguishers.
CO2 fire extinguishers come in 2 and 5-kg sizes.
What are CO2 fire extinguishers used for?

Fires involving equipment such as computers, or generators (‘electrical’
fires)

Fires involving some flammable liquids, such as petrol, diesel, and paint
(‘class B’ fires)
Do not use CO2 extinguishers for:

Fires involving oil and grease (Class F fires)
Wet chemical fire extinguishers
Wet chemical fire extinguishers (also known as Class F fire extinguishers) are
the only extinguisher that can safely be used for fires involving cooking oil;
therefore, they are essential in professional kitchens and fast food
restaurants.
Wet chemical fire extinguishers have a yellow label saying ‘Wet Chemical’.
They also have a longer hose than the standard extinguishers and have an ID
tag saying ‘Wet Chemical Extinguisher’.
Potassium is the chemical component of the fire extinguishers, and the
chemical is gently sprayed out to not burn the fats and oils. It creates a film
over the grease to suffocate the fire.
Whilst they are excellent and extinguishing grease fires, they can produce
toxic fumes, so areas must be ventilated.
Wet chemical fire extinguishers are available in 2, 3, and 6-litre sizes.
What are wet chemical fire extinguishers used for?

Fires involving cooking oils and fats (Class F fires)

Fires involving flammable solids (Class A fires)
Some wet chemical fire extinguishers can also be used for fires involving
flammable liquids; however, the exact use will be written on the label.
Do not use wet chemical fire extinguishers for:

Fires involving flammable liquids (‘class B’ fires) UNLESS they are
specifically cleared for this use

Fires involving combustible gases, such as methane and butane ('class
C' fires)

Electrical fires
Conclusion
Propane vs. Butane — Key Differences
Feature
Boiling Point
Cold Weather Use
Energy Content
Propane
Butane
−42°C
−0.5°C
✅ Excellent in winter
Slightly lower per liter
❌ Poor – doesn't vaporize well in cold
Slightly higher per liter
Feature
Storage
Best For
Propane
Larger tanks or cylinders
Outdoor, cold, industrial
Butane
Small canisters or cartridges
Indoor, portable, warmer climates