Fire Saftey: Three Main Types of Fire Extinguishers and How to Effectively Use Them

I'm sure you've noticed there are generally a bountiful amount of fire extinguishers at your place of work or school. Some of these fire extinguishers are red, and others are silver and shiny. They all do the same thing - extinguish fires, so they must all be the same, right? That's where you're wrong. Using the wrong type of fire extinguisher may actually be detrimental to your health, and may do minimal (if any) known down to the fire itself. For example: There's a computer tower that has caught fire at the office that you work at. As you look around you spot a shiny, silver fire extinguisher and try to put out the fire before it spreads to the rest of the office.

While you were in good heart, there is the possibility of you getting hurt since that type of fire extinguisher (shiny/silver) is generally known as a "Water Can", meaning it contains water (and sometimes other agents such as AFFF), and the computer is an electric appliance. The correct fire extinguisher for this job would have been a CO2 (class C) fire extinguisher. The "Water Can" (class A fire extinguisher) is used for paper and wood fires only.

Keep in mind that fire extinguishers should have a gauge stating how much extinguishing agent is left within the extinguisher. Also, remember that fire extinguishers should be properly checked and maintained.

The 3 Main Types of Fire Extinguishers:

The Water Can (Class A) - The Water Can is one of the most common types of fire extinguishers. Sometimes it only contains pressurized water, while other times it may also contain AFFF (Aqueous film forming foams), or other types of foaming agents that help knock down fires. The Water Can is used for paper, cardboard, plastic, and wood fires only, and under no circumstances should be used for oil, chemical, electrical, or combustible metal fires.

Dry Chemical (Class A, B, and C) - Dry chemical fire extinguishers are the most versatile extinguishers since they can knock down an array of different classifications of fires. This is the only class of fire extinguishers that should be used against an oil, gasoline, grease, or any flammable liquid fire. However, these extinguishers can be dangerous for close quarters since it's dispersant's work as a mild nerve agent.

Carbon Dioxide (Class B and C) - These types of fire extinguishers are generally used for electrical fires (see the example in the first paragraph), but they may also be used for class B fires as well. What the Carbon Dioxide (also known as CO2) fire extinguisher does is displace the oxygen from the fire, extinguishing it. The CO2 fire extinguisher should not be used on class A (wood, paper, cardboard, plastic, ect.) fires, as it may actually worsen the fire in the long run. I've seen first hand at the fire academy how weak this fire extinguisher is on a wood fire (it was a pile of wood pallets). Another firefighter completely shrouded the flaming wooden pallets with a CO2 fire extinguisher and did it minimal knock-back.

There are other kinds of fire extinguishers (for example: Class D [combustible metals] cans known as "Purple K"), but above are the three main types that the average person would see in general public areas.

Knowing which fire extinguisher to use is only half of what you need to know, now you need to know how to use it. There's a simple acronym you may see on walls at hospitals, schools, or your place of work that simplifies the methodology is utilizing a fire extinguisher. This acronym is known as "PASS". This stands for:
P - Pull the pin. This disengages the locking mechanism and allows you to utilize the fire extinguisher.
A - Aim at the base of the fire. This is the most effective and fastest way of knocking down a fire - at it's source.
S - Squeeze the handle to discharge the flame-fighting agent.
S - Sweep the projected firefighting-agent at the base of the fire to extinguish it successfully. As the flames diminish you may get closer, but always keep a safe distance from the fire. Check whichever fire extinguisher you're using for more detailed information on safe operating distances.

There are many classes out there that teach you about fire and it's classification hands-on, and also allows you to actually use an array of fire extinguishers. Check with your local fire department and/or fire academy regarding this if you'd like to continue to learn or get a real hands-on learning experience about fire extinguishers.