Types of Fire Extinguishers – Portable Fire Extinguishers
If a fire breaks out, you may be tempted to grab the nearest portable fire extinguisher to try to put it out. But before you do, make sure you know the following:
- Are you sure that the fire is not too large to be put out with a portable fire extinguisher?
- Is the extinguisher you have the right type or size for that fire?
- What is the proper sequence of steps to be taken when using a portable fire extinguisher?
Unless you know the answers to all of these questions, you should not attempt to extinguish a fire. Otherwise, your actions could result in extensive property damage, as well as injury and even death.
The Occupational Safety and Health Administration (OSHA) regulates portable fire extinguisher use in the workplace. While fire extinguishers are addressed in many other sections of the OSHA regulations, the primary OSHA standards regarding fire extinguishers in construction are found in 1926:150 (Construction) and the primary standards for general industry are found in 1950:157.
When portable fire extinguishers are provided for employees in the workplace, OSHA requires employers to provide their employees with an educational program covering the principles of fire extinguisher use.
Employees must also be provided with information about the hazards associated with incipient, or early-stage, fire-fighting. In addition, actual hands-on training in the use of fire-extinguishers must be provided to those employees designated to use an extinguisher as part of their job such as fire brigade members and fire watchers.
This article covers the considerations for selecting the proper fire extinguisher for the type of fire you are facing.
It also explains the acronym PASS, which can help you remember the four sequential steps to operate a portable extinguisher.
We also discuss some Dos and Don’ts to remember every time you use a portable fire extinguisher.
The first thing to remember is that portable fire extinguishers are not intended for fighting large fires. They are only intended for use on what are known as incipient stage fires which are defined as follows:
- Are in their initial stages
- Can be handled safely using portable fire extinguishers
- Do not require the use of special personal protective equipment (PPEs) such as respirators
When faced with a large fire, immediately evacuate the area and alert others. You should also evacuate the area anytime you are not comfortable with using an extinguisher.
Proper Selection of Portable Fire Extinguishers
There are many different types of portable fire extinguishers and using the wrong type on a fire means that you may not be able to extinguish it safely and effectively. For example, almost everyone knows that oil and water do not mix. That is the reason you will not want to use an extinguisher that sprays water on burning liquids that can actually make the flames spread.
Some extinguishers are intended for use on a single type or class of fire materials while others are intended for use on a combination of two or more classes of fires. Just check the labels on your extinguishers to know which type or types of fires they are intended to extinguish.
Class A rated fire extinguishers will be marked with the appropriate symbols and are intended to use on ordinary combustible materials such as wood, paper, cardboard, dry vegetation and some plastics. Basically, anything that leaves an ash is a Class A fire material. Class A fire extinguishers often contain water that is sprayed on the fire material and should not be used to extinguish flammable liquid fire. Water should also not be used to extinguish an electrical fire.
Class B Rated fire extinguishers are suitable to use on fires involving flammable liquids such as gasoline, diesel, thinners, solvents, oil and grease. CO2 fire extinguishers, which contain gaseous carbon dioxide, displace the oxygen so that the fire cannot continue burning. These extinguishers are usually used on Class B fire materials. While they are effect, the CO2 can displace the oxygen in a small enclosed space and therefore only used these fire-extinguishers only where there is enough natural ventilation. Also, the horn shaped nozzle where the gas is discharged can become extremely cold- cold enough to cause frostbite. Caution should therefore be used when handling these type of extinguishers.
Class C Rated fire extinguishers mean they can be used in near or on areas involving energized electrical equipment. This designation is normally seen on combination type fire-extinguishers that are suitable to use on other types of fires too.
Class D Rated fire extinguishers are intended to be used on fires involving combustible metals which can actually burn such as magnesium, sodium or potassium.
Class K Rated fire extinguishers, which are the latest on the market are speciality fire extinguishers that are designed for use on kitchen fires, specifically those involving deep fryers which contain animal based oils or fats, as well as vegetable oils.
Some class of fire extinguishers are meant to be used on only one class of fire material such as class A, B or D.
However, most extinguishers are designed for use on two or more classes of fire material. For example, a foam extinguisher is rated for use on fires in class A and B.
The most prevalent fire extinguishers found in most work places are combination A, B and C.
These commonly contain a dry powder that can smother out a fire much like you would with a blanket.
They can be used to extinguish fires involving ordinary combustible material, flammable liquids and electrical equipment.
You should therefore check the labels of your portable fire extinguishers in your workplace so you will know what type or types of fires they are rated to extinguish.
One more thing to consider when you are using a portable fire extinguisher is the size.
A relatively small fire extinguisher will only last for six to ten seconds before emptying. A larger extinguisher (like a 20 ABC), will last somewhere between 25 to 35 seconds before it is emptied.
While that is a relatively longer time, most people are surprised at how fast even a large fire extinguisher can be completely emptied.
PASS Method of Using Portable Fire Extinguishers
There are four basic steps of using portable fire extinguishers. However, people often panic when they see a fire and forget exactly what to do. To help you remember the four basic steps of portable fire extinguisher use, just remember the acronym PASS. It stands for:
- Pull the pin. Stand several feet away from the fire while holding the extinguisher on one hand and then insert your finger on one end of the retainer pin and firmly pull. Don’t worry, because the thin plastic band that holds the retainer pin in place in most extinguishers will break relatively easy.
- Aim the nozzle or discharge hose at the base of the fire. The idea is to apply the fire extinguisher media at the material that is burning and not at the flames that may be leaping up high.
- Squeeze the handle to discharge the fire extinguisher. If you let go of the handle the discharge will stop and if you squeeze again the discharge will continue.
- Sweep from side to side as you slowly approach the fire. This allows you to cover all the burning material and not just that located in the centre of the fire.
Extinguishing Fires – Dos and Don’ts
- Maintain a safe escape path. Never get yourself in a position where you could be trapped should the fire spread. Always maintain a clear path to the nearest exit or other safe area and evacuate immediately if the flames, heat or smoke seem to be getting out of control.
- Once you have extinguished the fire, keep an eye out for flare-ups. Sometimes, the fire continues to smoulder below the burning debris and it is not uncommon for the fire to re-ignite several minutes later
- Beware of slippery floors. Fire extinguishing media such as foam and water can collect on the floor around a fire and cause you to slip, as can ash or liquids from containers that might have burst during a fire. So don’t run- just walk in a controlled manner so that you do not slip and fall.
- Keep an eye out for any boxes, pallets or other materials that are placed on shelves or stacked near the fire area as they could become unstable from fire damage and fall over on you.
- Recharge all used extinguishers. Turn over all extinguisher that have their pins pulled out to be checked. Even if did not squeeze the handle, you may have broken the internal seal that retains the pressure inside of the extinguisher. So play it safe and get it checked out.
Take some time to familiarize yourself with the various types of fire extinguishers around the workplace as well as any that you may have at home or in your vehicles.
If you discover a fire and you are going to attempt to extinguish it, notify someone else about the fire and then remember PASS. These are the four basic steps to use for portable fire extinguishers.
Also keep in mind the importance of maintaining the awareness of your surroundings so that you do not become trapped or injured when trying to put off a fire.
Finally, never attempt to use a fire extinguisher if you are not comfortable doing so. Instead, you should evacuate and go to a safe area as prescribed in your organization’s emergency action plan.
If you have any questions about the use of portable fire extinguishers, talk to a safety supervisor at work.