dry chemical fire extinguisher

The aim of most safety plans is to create an environment where there are no fires. When a fire does occur, it may be the the difference between success and failure to have a trained person operating the fire extinguisher.

Fire Extinguishers are placed in buildings by designers for a number of reason but  the most important purpose is to help trained personnel mitigate the risk to occupants life. There are a number of Australia Standard that guide building designers in relation to appropriate placement and many other aspects. Some of the Australia standards are:

  1. Portable fire extinguishers General requirements – AS/NZS 1841.1:2007
  2. Wheeled fire extinguishers – AS 4265-1995
  3. Portable fire extinguishers and fire blankets – Selection and location – AS 2444-2001

Using a fire extinguisher

Through Out Melbourne and Victoria

fire extinguisher graphicOften during training when a participant is asked to demonstrate the use of a fire extinguisher, it provokes a sense of anxiety. This may be considered a normal response as it is something a participant has never done before. That’s one of the reasons the first time one uses a fire extinguisher shouldn’t be in a real emergency situation. They are simple to use and  designed with the user in mind, but training will help you make informed, sometimes critical decisions in an emergency. In reality the operator only requires a very small amount of theoretical and practical training.

One acronym used to guide the learner through the process is P.A.S.S.

  • Pull the pin
  • Aim the nozzle
  • Squeeze the trigger
  • Sweep the content across the fire
  • Its generally that simple.

This acronym may be a simple and easy guide, but in some respects doesn’t tell the whole story. Before the user gets to the point of firefighting a number of small but critical decisions must be made. This is where training is required to establish the greater process. The types of extinguishers and their uses are detailed below, but to simplify what to do in an emergency involving fire is pretty straight forward. They include:

  1. Identifying what type of fire that is present and whether it is to large for the size of extinguisher available
  2. Are there any hazards that may affect fire extinguisher selection. i.e. electrical hazards (the extinguishing agent would need to be non conductive – eg: dry chemical where electricity is present)
  3. Once we have made a decision only then can we start to fight the fire and use the PASS process.
  4. As we approach the fire there is a need to test the extinguisher before starting to fight the fire – equipment fails and your must be sure it is working or your life could be in danger.

Review the following card to learn about the classes of fire.

This information is covered in all accredited fire extinguisher training.

fire extinguisher identification guide
Fire extinguisher identification guide.

Useful Resouces (PDF):

  1. Fire Extinguisher Training Worksheet
  2. Fire Extinguisher Fact Sheet

*Courses available across Melbourne and Victoria.

Types of fire extinguishers in Australia

The water extinguisher

The first one we will cover is the water fire extinguisher. All extinguishers are red and this one has a label which is red and would be used for fire involving carbonaceous materials like paper, wood, plastics and the like. Also known as class “A” fires.

The action of this extinguisher removes the heat from the fire triangle by cooling the burning product. Water conducts electricity and therefore should not be used where there is a risk of electric shock.

sound cloud images of the fire extinguisher track
If you would prefer to listen to the article click on the image.

The carbon dioxide extinguisher

Again a red extinguisher but this time has a black band indicating that it is in fact a carbon dioxide extinguisher. It is safe to use on electrical fire where the water extinguisher was not safe. It will not give you a shock as it does not conduct electricity and generally will not damage the equipment you are using it on.

Prior to using this extinguisher it is always a good idea to turn off the supply of electricity if safe to do so. These extinguishers also have limited effect on a class “B” or flammable liquid fire. They should be used with extreme caution as the fire may reignite if the flames have been extinguished. A CO2 extinguisher puts out the fire by smothering or displacing the oxygen and therefore shouldn’t be used in a small or confined space. If this precaution isn’t observed the user may be overcome by the lack of oxygen in the surrounding environment.

They can also unsettle the untrained or not confident user as as the suppressant exits the extinguisher it creates a very loud noise. Therefore during training it is advisable that hearing protection is used.

The golden rule is to place the discharge horn at ninety degrees to use and not touch is again while in use. As the CO2 is expelled the discharge horn will become very cold and this can cause nasty cold burns to exposed skin.

The foam extinguisher

The next extinguisher we will talk about is the foam extinguisher. It is generally red with a blue label. Even so, there are some older types around that are totally blue. This extinguisher is generally used for class “B” or flammable liquid fires and is water based. Due to this fact it can be quite effective on class “A” fire also.

With flammable liquid fires, for which it is generally designed, it puts a layer of foam over the burning liquid thus stopping the vapour release. In all flammable liquid fire it is the vapour that is burning. So because the vapour has been stopped from being released the fire can’t continue thus going out quite rapidly.

Because the foam extinguisher is water based it must not be used on electrical fires.

fire extinguisher used to protect the boats


The Dry chemical or powder extinguisher

This red extinguisher with a white band is probably the most versatile extinguisher, but again does have some limitations.

It is not water based and therefore is suitable for electrical fire as it should not conduct electricity. It can be used on carbon based fire as will as flammable liquids. There is always the possibility of re ignition as it will not cool the burning material. The powder itself will supply a very small amount of smothering. I.e. isolating the oxygen from the fuel, but generally works on the chemical chain reaction or flame.

In every flame there are a number of unmatched electrons which fly around releasing energy, thus the flame. What the dry chemical extinguisher does is provide matching electrons for those unmatched and the flame goes out. This could be said to have stopped the chemical chain reaction.

It is still important to note that there is no cooling provided so burning could recommence if the fuel is at its ignition point.

shoot out all fires with a fire extinguisher before they become big

Let’s now look at raising the alarm of fire

The most important thing to do in the event of discovering a fire is to raise the alarm by using an appropriate communications method. Thus it is important to follow the general fire orders which are generally located in a prominent position near new firefighting equipment or an evacuation plan.

Now using a fire extinguisher to extinguish the fire. It is important that a fire extinguisher is only used if safe to do so and operated by a trained and confident person. The first time you use a fire extinguisher shouldn’t be in a real emergency situation.

Ensure the fire is within the capability of the fire extinguisher which means it should be relatively contained and not getting too big, i.e. in a rubbish bin. Also, if it is very smoky make sure that you do not enter the smoke as often the gasses given off by a fire can be deadly and your life and others may be put in real danger. Lastly make sure that you have the appropriate extinguisher for the situation. If the fire was a result of an electrical hazard then a water extinguisher would be very dangerous.

Escalating emergency situation

There is a need to recognise that an escalating emergency situation will not hinder your evacuations if required . So before starting the fire attack make sure you are between the fire and an exit and that it is clear. If there are any doubts, get out.

When you have considered all of the safety issues and any others mentioned about you can then use the extinguisher to attack the fire using the pass method.

PASS is an acronym that provides the sequence for using the equipment. Each letter stand for the following:

  • P = Pull the pin
  • A = Aim at the base of the fire
  • S = Squeeze the trigger slowly
  • S = Sweep from side to side.

Also remember to test the extinguisher as you approach the fire. You do not want to get within fighting distance and realise the extinguisher is unserviceable.

In conclusion

Hopefully this has refreshed your memory. Even so, it is important that you are trained and confident with the use of firefighting equipment. Generally, required under the building code of Australian in a facility/ business. Equipment provided for occupant use is very simple to use but if not used appropriately can place the user in a dangerous situation. Imagine the potential result of using an extinguisher on an electrically energised fire. Good Luck.

By Ken Walker

Hi, I'm Ken. I am the owner and senior director of Syncretic training Group Pty Ltd. If you have any questions about the website content or require guidance please let us know we are always happy to help.

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