A simple guide
There are six main portable fire-extinguisher types; Water, Foam, Dry Powder, Vaporising Liquid, CO2 and Wet Chemical. You should have the right kinds of fire-extinguisher for your premises, or you may not be compliant with the Australian standards, and more importantly, may not be able to tackle an emergency effectively.
The various fire-extinguishers are designed to put out fires consisting of different fuels, that is the ‘class’ of fire. The risk from the different fuel classes will determine which fire-extinguisher types you need.
As well as the right type, you will also need to make sure that you have the right size and weight (capacity) of fire-extinguisher for the potential risk.
The six types of fire-extinguisher
- Water
- Foam
- Dry Powder
- Vaporising Liquid
- Carbon Dioxide (CO2)
- Wet Chemical
Some of these types are also available in different versions; for example, you can get ABE category dry powder and BE category dry powder extinguishers. However, to keep this guide simple, we will stick with the ‘main’ versions.
There is no one portable fire-extinguisher type which works on all classes of fire.
Below is a summary of the classes of fire. We then provide a detailed explanation of each type of fire-extinguisher below.
The classes of fire
There are six Australian classes of fire:
- Class A combustible materials: caused by flammable solids; wood, paper, and fabric
- Class B flammable liquids: such as petrol, turpentine or paint
- Class C flammable gases: like hydrogen, butane or methane
- Class D combustible metals: such as magnesium, aluminium or potassium
- Electrical electrical equipment: once the electricity is isolated, the fire changes class
- Class F cooking oils: typically, a chip-pan fire
Water Extinguishers
Water extinguishers are a common fire-extinguisher type for class A fire risk; however, in recent years many premises now use ABE category Dry Powder fire-extinguishers due to the extra flexibility they provide.
Label Colour: Bright Red
Use for:
Organic materials:
- Paper and cardboard
- Fabrics and textiles
- Wood and coal
Do not use for:
Fires involving electrical equipment
Kitchen fires
Flammable gas and liquids
How water extinguishers work:
The water has a cooling effect on the fuel, causing it to burn more slowly until eventually extinguished.
Types of premises/business who may need water extinguishers:
Buildings constructed of wood or other organic materials
Premises where natural materials are found:
- Offices
- Schools
- Hospitals
- Residential properties
- Warehouses
Where to locate water extinguishers:
By the exits on a floor where a Class A fire risk has been identified
Foam Extinguishers
Foam extinguishers are a common type of fire-extinguisher for Class B fires, but also work on Class A fires as they are water-based.
Label Colour: Blue
Use for:
Organic materials such as:
- Paper and cardboard
- Fabrics and textiles
- Wood and coal
Plus:
Flammable liquids, like paint and petrol
Do not use for:
Kitchen fires
Fires involving electrical equipment
Flammable metals
How foam extinguishers work:
As with water extinguishers, foam extinguishers have a cooling effect on the fuel. On burning liquids, the foaming agent creates a barrier separating the flame and the fuel, extinguishing the fire.
Types of premises/business who may need Foam extinguishers:
Buildings constructed of wood or other organic materials
Premises where there are organic materials to be found such as:
- Offices
- Schools
- Hospitals
- Residential properties
- Warehouses
Buildings where flammable liquids are stored
Where to locate foam extinguishers:
By the exits on a floor where a Class A or Class B fire risk has been identified
Dry Powder Extinguishers
One of the most flexible of all the fire-extinguisher types.
Although they can extinguish electrical fires, caution should be exercised especially where the electrical equipment is of high value or delicate, as the resulting powder can be corrosive and difficult to clean up. Should not be used in an enclosed space where the powder may be inhaled.
Specialist dry powder extinguishers are used for flammable metals.
Label Colour: White
Use for:
Organic materials such as:
- Paper and cardboard
- Fabric and textiles
- Wood and coal
Plus:
Flammable liquids, like paint and petrol
Plus:
Flammable gases, like liquid petroleum gas (LPG) and acetylene
Plus:
Fires involving electrical equipment up to 1000v
Specialist dry powder extinguishers are only used on flammable metals, such as titanium and magnesium.
Do not use for:
Fires involving cooking oil
Fires involving electrical equipment over 1000v
or in enclosed spaces
How dry powder extinguishers work:
Dry powder extinguishers smother fires by forming a barrier between the fuel and the source of oxygen.
Types of premises/business who may need Dry Powder extinguishers:
Businesses using flammable gases for chemical processes
Premises where welding and flame cutting takes place
Garage forecourts
Liquid petroleum gas (LPG) dispensing plants
Premises with large, commercial boiler rooms
Where to locate Dry Powder extinguishers:
Place dry powder extinguishers near to the source of the fire risk, or on the exit route
Specialist Dry Powder extinguishers what’s the difference?
Specialist dry powder extinguishers work in the same way as standard dry powder extinguishers but are for use with flammable metals. If your premises require a specialist extinguisher you will need to seek advice on the specific type required.
Carbon Dioxide (CO2) Extinguishers
CO2 extinguishers are predominantly used for electrical fire risks and are usually the main fire-extinguisher type provided in computer server rooms. They can also put out Class B fires (flammable liquids, such as paint and petroleum).
Label Colour: Black
Use for:
Flammable liquids, like paint and petrol
Electrical fires
Do not use for:
Kitchen fires especially chip-pan fires
Combustible materials like paper, wood or textiles
Flammable metals
How CO2 extinguishers work:
CO2 extinguishers suffocate fires by displacing the oxygen the fire needs to burn.
Types of premises/business who may need CO2 extinguishers:
Premises with electrical equipment, such as:
- Offices
- Kitchens
- Construction sites
- Server rooms
Where to locate CO2 extinguishers:
Place near to the source of the fire risk and/or near the fire exits.
Vaporising Liquid Extinguishers
Vaporising liquid extinguishers are designed for use on Class A and Electrical fires.
Label Colour: Yellow
Use for:
Organic materials such as:
- Paper and cardboard
- Fabrics and textiles
- Wood and coal
Electrical fires
Do not use for:
Flammable liquid or gas fires
Flammable metals
How vaporising liquid extinguishers work:
Discharges a rapidly evaporating liquid which leaves no residue. It effectively extinguishes Class A and can be effective on Class B fires by cooling and smothering and it will not conduct electricity back to the operator, so can be used on electrical fires.
Types of premises/business who may need vaporising liquid extinguishers:
Offices
Workshops
Warehouse/storage
Where to locate vaporising liquid extinguishers:
Place on the exit routes.
Wet Chemical Extinguishers
Wet chemical extinguishers are designed for use on Class F fires, involving cooking oils and fats. They can also be used on Class A fires although it is more usual to have a foam or water extinguisher for this type of fire risk.
Label Colour: Pale Yellow (Beige)
Use for:
Cooking oil/fat fires
Organic materials such as:
- Paper and cardboard
- Fabrics and textiles
- Wood and coal
Do not use for:
Flammable liquid or gas fires
Electrical fires
Flammable metals
How wet chemical extinguishers work:
Wet chemical extinguishers create a layer of foam on the surface of the burning oil or fat, preventing oxygen from fuelling the fire any further. The spray also has a cooling effect.
Types of premises/business who may need wet chemical extinguishers:
Commercial kitchens
Canteens
Where to locate wet chemical extinguishers:
Place near to the source of the fire risk.
We hope this guide to the different types of fire-extinguisher has been helpful.
If you still have questions, or if you’d like to book a free survey of your premises by one of our qualified extinguisher technicians, please just call us on (08) 6245 2677 or email us at info@paramountservices.com.au and we will get back to you.