Fire Extinguisher
All You Need To Know About Fire Extinguishers
And How To Choose Them
When it comes to fire safety in the home or workplace, you should leave no stone unturned. There can be any number of reasons for a fire to erupt inside a property. It can be something as small as a spark in a wall socket, to something as big as a gas leak. No matter what the reason, it can be devastating for the entire structure, even more so for the people inside it.
One of the best lines of defence to protect your property from fire accidents is to buy and install fire extinguishers at strategic and easy-to-reach locations inside the premises, so that you can quickly grab it and douse it on the fire. This article covers everything you need to know about fire extinguishers, and will also guide you on how to choose the right one.
How do Fire Extinguishers Work?
Before we discuss how fire extinguishers work, let’s have a look at the elements involved in starting a fire. Basically, a fire needs three things to erupt and burn: air, heat, and fuel. The oxygen in the air is an accelerant that causes the fire to spread throughout a building or property. If you remove any one of the three, you will successfully put out the fire.
Consider it like this: if the top of your frying pan catches fire, you can start by turning off the gas, which would remove the heat from the equation. However, since the fire is burning, this only reduces the heat. What you can do is use a wet towel or cloth and put it on top of the pan. This will cover the fire and restrict the airflow, thus cutting off oxygen supply. Of course, you can’t use a dry cloth, or it can also catch fire.
Therefore, fire extinguishers are designed to remove heat, oxygen, or both from a fire. There are different types of fire extinguishers, and most of them contain compressed carbon dioxide. When this comes in contact with the fire, it removes oxygen from the equation, thus putting out the fire effectively. Since it is compressed, the carbon dioxide gas is also cold and thus also removes heat from the fire or burning item.
What are the Different Classes of Fire?
To determine what type of fire extinguisher you should get for your home, office, factory, or any other building, you will have to know about the different classes of fire first. There are six different classes of fire, which are as follows:
- Class A: Fires with solid materials, like wood, paper, or textiles
- Class B: Fires caused by liquids like oil, petrol, diesel, etc.
- Class C: Fires caused by gases
- Class D: Fires that burn metals, such as aluminium or lithium
- Class E: Electrical fires/ fires involving electrical fixtures or appliances
- Class F: Fires caused due to cooking oils
Each class determines the type of extinguishing agents or solutions that can be used to put out the fire, and subsequently, there are different types of fire extinguishers for each of them. Some of the widely used extinguishing agents include water, wet chemicals, carbon dioxide, and some others.
Now that you have a basic idea of the different fire classes, let’s have a look at the different types of fire extinguishers and see which one is suitable for each class.
What are the Different Types of Fire Extinguishers?
Let’s have a look at all of the fire extinguishers you can find out there, and how each one can be used to put out various types of fires.
Water Extinguishers
Water extinguishers are known to be one of the most affordable and effective fire extinguishers, and they are mostly used to combat Class A fires, which involve the burning of paper, wood, textiles, and other similar materials. Water extinguishers can be identified by the red label on them, so you can also recognize them from a distance.
Water extinguishers can be further classified into various categories:
- Water Jet Extinguishers: This type of extinguisher is used to spray a jet of water at high speed on the burning materials, thus removing their heat and inhibiting further combustion. They are only suitable for Class A and should never be tried on Class E fires, which involve electrical components, especially if the electricity hasn’t been shut down.
- Water Spray Extinguishers: These fire extinguishers use a very fine spray of water droplets, each of which is non-conductive. They can be used for Class E fires as well, as they are tested on a 35kV electrical source.
- Water Extinguishers with Additives: These fire extinguishers feature water mixed with foaming chemicals, and this causes the water to penetrate the burning materials deeply. Therefore, they can be used for Class A and B fires.
- Water Extinguishers with Additives: These fire extinguishers feature water mixed with foaming chemicals, and this causes the water to penetrate the burning materials deeply. Therefore, they can be used for Class A and B fires.
Foam Extinguishers
This type of fire extinguishers is filled with Aqueous Film Forming Foam, or AFF Foam, and they can be used to put out Class A and B fires, which include paper, textiles, cardboard, petrol, diesel, or certain oils. This makes them much more versatile and useful than water extinguishers, which can mostly be used for Class A fires only. Foam extinguishers feature a cream-colored label on them.
Foam extinguishers are particularly effective at dousing liquid fires. When you point the nozzle and release the foam on the burning materials, it seals the surface of the fuels, thus restricting the flow of air and preventing oxygen from fanning the flames any further. However, foam extinguishers are mostly suited for contained liquid fires, and not free flowing fires, because they would be ineffective in those conditions.
Another thing to keep in mind is that foam extinguishers are largely ineffective against Class F fires, which are caused due to cooking oils. They may be used for putting out Class E or electrical fires, but you will have to spray the foam from very close, which may not be possible for you without getting yourself injured. It can also be difficult to clean up after you have put out a fire using a foam extinguisher, since the foam leaves behind a lot of residue.
Powder Extinguishers
Powder extinguishers are much more useful and versatile as compared to water and foam fire extinguishers. They are suitable for putting out Class A, B, and C fires, so you can use them to smother gas-based fires in addition to petrol, diesel, paper, textiles, or cardboard. You may also find specialized powder fire extinguishers that may be able to combat Class D fires as well. Powder extinguishers are categorized and distinguished by their blue label.
When you spray this type of fire extinguisher on a fire, the powder releases and forms a crust over the fire when it gets heated. This smothers the fire and blocks all airways for oxygen to pass through, thus inhibiting combustion. However, since the powder may not go deep inside the burning materials, these extinguishers fail to remove heat from them, and this may still leave a chance for re-ignition.
Moreover, the dry powder used inside these extinguishers is hazardous to health, which is why these fire extinguishers are difficult to use in closed spaces that don’t have any ventilation.
Carbon Dioxide (CO2) Extinguishers
Carbon dioxide extinguishers are one of the most common types of fire extinguishers, and they are mostly installed inside homes, offices, factories, workplaces, and many other places. These extinguishers are filled with pressurized carbon dioxide gas, which is also quite cold due to the pressure. They are suited to put out Class B, which involves burning liquids and fuels, as well as Class E fires, which are often caused by faulty wiring or short circuits and are common in homes and offices.
Carbon dioxide extinguishers have a black label on them. When this type of fire extinguisher is sprayed, it releases carbon dioxide that removes oxygen from the equation and also cools down the burning materials, thus reducing any chances for re-ignition. Plus, it also doesn’t leave any kind of residue, so you don’t have to worry about cleaning up.
Wet Chemical Extinguishers
Another type of fire extinguishers is wet extinguishers, which feature a wet chemical inside them. They are particularly suitable for putting out Class F fires that are caused by cooking oils. This makes them one of the two fire extinguishers that are effective against Class F fires, the other being water mist extinguishers. Apart from this, they can also be used for putting out Class A and B, which also makes them quite useful.
These extinguishers have a yellow label on them, and they are filled with a pressurized solution of alkaline salts in water, which create a fine mist, just like water mist extinguishers. When sprayed on the fire, the solution evaporates quickly and also absorbs heat energy, thus causing the fire to die out quickly before it can spread anywhere.
How to use Fire Extinguishers?
If you are getting a fire extinguisher for your home or office, or any other space, then you must also know how to use it. Ideally, fire extinguishers should only be operated by people who have professional training to put out fires, but such people aren’t always around when a fire breaks out. Therefore, you should think about getting proper training. One of the most important things to remember that you should only start using a fire extinguisher on a fire when most of the people have evacuated the building or at least cleared out the space where a fire has started.
It is always ideal to have a fire alarm installed before you use the fire extinguisher. By doing so, you will be immediately alerted about the smallest fire and you will be able to bring other people to safety before you attempt to put out the fire.
If you don’t want to receive any formal training, you can have a look at the following steps that you can apply to use a fire extinguisher properly.
Pull
There is a pin located just beneath the handle, which locks the handle and prevents any accidental usage of the fire extinguisher. You have to remove it to break the tamper seal.
Aim
Next, grab the fire extinguisher and point its nozzle to the base of the fire, for which you will have to aim low rather than somewhere in the middle. If you have a CO2 extinguisher, with a black label, make sure to keep your hands off the horn, as it can be very cold.
Squeeze
Once you have aimed the nozzle, squeeze the handle with all your force, and this should cause the extinguishing agent to release towards the fire.
Sweep
With the handle pressed, move the nozzle from side to side in a sweeping motion. This will allow the extinguishing agent to cover a greater surface area and increase the chances of smothering the fire. Keep doing this, and don’t release the handle, until you notice the fire dying out.
The above steps can be memorized by remembering the acronym: P.A.S.S (Pull, Aim, Squeeze, Sweep).
What are Other Types of Fire Extinguishers?
The fire extinguishers that we have mentioned above refer to the red-coloured cylindrical containers that you may have noticed in public spaces, offices, and other buildings. However, there are other types of fire extinguishers as well. For starters, you can also find automatic fire extinguishers, which are mostly used in vehicles and are activated if there is a fire in the engine bay.
Apart from these, you can also find smaller fire extinguishers and place them inside your vehicle, in case there is a short circuit in the wiring that leads to a fire. Not only that, but you may also be able to use your fire extinguisher to help someone else on the road, or if you notice a vehicular fire close to yours.
This brings us to the end of our guide on fire extinguishers and how you can choose the best one for your home, office, or property. Fire safety is always of paramount importance and should never be neglected. You may think that since you have never experienced such an incident, you don’t need fire extinguishers, but they can be the one difference between life and death for you or the people around you.