Fire Extinguisher Types
The different types of fire extinguisher available and how to use them
There are many different types of fire extinguisher available on the market, here we will discuss the 5 you are most likely to encounter. It is important however to note that in certain industries you may have specific types of fire extinguisher that are usually for specific risks. These will not be covered on this page and require specialised training and familiarisation.
Selecting the right extinguisher type is incredibly important as selecting the wrong type can have consequences from failure to effectively put out the fire (insufficient knockdown) through to injury or death. The different classes of fire are covered in more detail here.
All Portable Extinguisher Types
All portable extinguishers have a few things in common.
Stored Pressure
Normal portable fire extinguishers in Australia operate on the stored pressure principal, this means that they are a pressurised cylinder containing the agent and a gas under pressure. When you squeeze the handle you release the pressure allowing the cylinder to discharge the agent.
Coloured Band
Extinguishers can be identified by the coloured band located near the top of the extinguisher, each type of extinguisher has its own colour that will be discussed in the section on that type.
Safety Pin
Extinguishers have a safety pin that prevents the handle being squeezed down until it is removed. This prevents unwanted discharges from objects hitting the handle, people leaning on the extinguisher or during transport. Remember to remove the pin before you try and squeeze the handle, otherwise you will find it difficult or impossible to remove the pin until you stop squeezing.
Hose and Nozzle
While some smaller types only have a nozzle the vast majority of fire extinguishers have a hose and nozzle. The hose allows the user to hold it in one hand while operating the handle with the other, to make directing the flow of agent easier. The nozzle is designed to deliver a specific pattern of agent and differs between types and brands, so it is important to quickly test the fire extinguisher before attempting to use it so that you know how far the agent will travel and what pattern it will form.
Squeeze Handle
The majority of fire extinguishers you will see operate by a squeeze handle on the top of the cylinder. When you depress the upper arm it pushes a pin down, allowing the gas and agent to flow past it and into the hose and nozzle.
Pictographs
Extinguishers have square icons located on the label indicating both the classes of fires that it can be used on (in green), and classes of fire that it is actively dangerous to use the extinguisher on (in a red strikethrough circle)
Label
The label contains information telling you what type of fire extinguisher it is, how much agent it contains and the extinguishers weight. Also on the label will be instructions for use both written and drawn in case you need to remind yourself how to use it.
Dry Chemical Powder
Dry chemical powder extinguishers, often known as simply "powder" or "ABE" fire extinguishers have a white band.
How does it work?
ABE powder fire extinguishers work by smothering the fuel in an agent separating parts of the fire triangle. The most common powder agent is AB(E) monoammonium phosphate. This melts and flows at 117°c, smothering the fire.
What classes can it be used on?
Dry Chemical Powder (ABE) extinguishers can generally be used effectively on:
Class A (Combustible Solid)
Class B (Flammable Liquid)
Class C (Flammable Gas)
Class E (Electrically Energised)
What classes should it not be used on?
Dry Chemical Powder (ABE) extinguishers should not be used on:
Class D (Combustible Metals - Insufficient Knockdown)
Class F (Cooking Oils and Fats - Insufficient Knockdown)
Are there any extra considerations when using Dry Chemical Powder fire extinguishers?
Powder extinguishers produce a significant cloud of fine powdered agent when used, which can restrict vision and irritate the eyes and airways. In an enclosed space this may make rescue or evacuation operations more difficult.
After use a powder extinguisher will generally require significant cleanup and the agent is corrosive and can damage sensitive electronics if they are left exposed to it.
Carbon Dioxide
Carbon Dioxide extinguishers, often known as"CO2" fire extinguishers have a black band and contain pressurised carbon dioxide.
How does it work?
CO2 fire extinguishers work by displacing the air with carbon dioxide, smothering the fire.
What classes can it be used on?
CO2 extinguishers can generally be used on:
Class B (Flammable Liquid)
Class E (Electrically Energised)
What classes should it not be used on?
CO2 fire extinguishers have limited effectiveness on:
Class A (Combustible Materials - Dissipates too quickly)
Class C (Flammable Gases - Dissipates too quickly)
Class F (Cooking Oils and Fats - Dissipates too quickly)
Furthermore, CO2 fire extinguishers should never be used on:
Class D (Combustible Metals - Risk of explosion)
Are there any extra considerations when using Carbon Dioxide fire extinguishers?
CO2 is a very clean extinguishing agent leaving behind no residue and not substantially obscuring vision or irritating the eyes and airways, however CO2 has very little dwell time as it is easily mixed with and displaced by regular air. This means that when you use a CO2 fire extinguisher you need to be aware that the fire may easily reignite as the agent doesn't cling to the fuel or form a barrier.
Foam
Foam extinguishers have a blue band and contain water, a foaming agent and a pressurised gas to expel the contents.
How does it work?
Foam fire extinguishers work by forming a foaming layer over the top of the burning fuel, smothering the fire.
What classes can it be used on?
Foam extinguishers can generally be used on:
Class A (Combustible Materials)
Class B (Flammable Liquid)
What classes should it not be used on?
Foam fire extinguishers should not be used on:
Class C (Flammable Gases - Ineffective)
Class D (Combustible Metals - Violent Reaction, Risk of Explosion)
Class E (Electrically Energised - Electric Shock)
Class F (Cooking Oils and Fats - Aggressive Reaction)
Are there any extra considerations when using Foam fire extinguishers?
Foam fire extinguishers are best used on contained flammable liquid fires. If possible aim the foam so that it lands on a vertical surface or wall of the area and slides down to cover the surface of the burning liquid without disturbing or agitating the surface. If you don't have a vertical surface to direct the foam against make sure you apply it as gently as possible to avoid disturbing the burning liquid and potentially splashing or spreading the fire.
It is important to remember that a foam fire extinguisher is still water based, so it will conduct electricity.
Water
Water extinguishers have a red band (In practice the whole extinguisher is the same red colour) and contain water and a pressurised gas to expel the contents.
How does it work?
Water fire extinguishers work by cooling the fire with water. As the water heats up and changes phase from a liquid to a gas (boiling) it absorbs enormous amounts of heat capable of quickly and efficiently cooling a fire.
What classes can it be used on?
Water extinguishers can generally be used on:
Class A (Combustible Materials)
What classes should it not be used on?
Water fire extinguishers should not be used on:
Class B (Flammable Liquids - Aggravates the fire)
Class C (Flammable Gases - Ineffective)
Class D (Combustible Metals - Violent Reaction, Risk of Explosion)
Class E (Electrically Energised - Electric Shock)
Class F (Cooking Oils and Fats - Violent Reaction, Risk of Explosion)
Are there any extra considerations when using Water fire extinguishers?
Water is an extremely good extinguishing agent, however it is limited to use on Class A fires. While this sounds like a significant limitation it is important to remember that the vast majority of materials in our environment are Class A materials. If the electrical hazard can be removed, such as by killing the power source, then the vast majority of fires can be extinguished with water.
However as there are many classes of fire that have actively harmful reactions to water it is important to be sure none of them apply before attempting to use water.
Wet Chemical
Wet Chemical extinguishers have an oatmeal band and contain a chemical agent, water and a pressurised gas to expel the contents.
How does it work?
Wet Chemical fire extinguishers work by forming a soapy layer on top of burning oil, excluding air and preventing the fire obtaining oxygen.
What classes can it be used on?
Wet Chemical extinguishers can generally be used on:
Class A (Combustible Materials)
Class F (Cooking Oils and Fats)
What classes should it not be used on?
Wet Chemical fire extinguishers should not be used on:
Class B (Flammable Liquids - Aggravates the fire)
Class C (Flammable Gases - Ineffective)
Class D (Combustible Metals - Violent Reaction, Risk of Explosion)
Class E (Electrically Energised - Electric Shock)
Are there any extra considerations when using Wet Chemical fire extinguishers?
Wet Chemical is primarily found in commercial kitchens where there are large deep fryers or other heated oils as it is specifically designed to interact with cooking oils and fats to form a soapy layer.
As the agent is still water based the usual considerations apply when using it, namely that of electric shock or the potential for a violent reaction with metals.