Before I get started, let me give you a little bit of my background. My family and I have been in the fire equipment business for a long time. My uncle started in 1970, and I started in 1980. During those years, fire fighting equipment has gone through many changes and advances, yet fire still claims the lives and property of the unprepared.
It is amazing to me, how many people I have met , who don't know how to use a fire extinguisher. It is also shocking to know that there are a great many people who don't know where the fire extinguisher in their workplace is located. Hopefully this article will help.
Before you fight a fire, it helps to understand it. Many of you may already know that fire is a chemical reaction, and there are the basic elements of heat, fuel, oxygen, and/or an ignition source. If any of the basic elements are removed, the fire will die. The basic elements of a fire are often referred to as: The fire triangle.
Now, let's take a look at the different classes of fires.
Looking at the classes of fires, you can determine which type of fire extinguisher to use, according to the hazard. For simplicity, class A fires involve any material that produces an ash. Class A fires can generally be put out by water.
2.5-Gallon Pressurized Water Fire Extinguisher
Class A fires can also be put out by other fire extinguishers, such as: Afff (Aqueous film forming foam), ABC dry chemical (monoammonium phosphate), Halon (bromodiflouromethane), Halotron, and soda and acid (Generally no longer used).
Deionized Water Mist Fire Extinguisher
2.5-Gallon AFFF (Foam) Extinguisher
9-Pound Halon 1211
5-Pound ABC dry chemical extinguisher.
1920's Soda and Acid by Elkhart Brass Company
Soda and acid extinguishers are no longer in use, and in many states, they are illegal.
As you can see from the pictures, there is more than one type of extinguisher for a particular application.
A class "B" fire involves flammable liquids, and depending on the temperature of the flame, determines the best extinguisher for the hazard. For example: An ABC fire extinguisher can be used on a grease fire, but it probably won't be as effective as a class "K" liquid extinguishing agent - which has the ability to cool down the grease.
Also. depending on whether the grease fire is animal fat or vegetable oil will make a big difference. Vegetable oil burns with a higher temperature, and the old fashioned baking soda trick won't work very well. Baking soda is the main ingredient in a BC dry chemical fire extinguisher, and it works by smothering the fire, and providing a barrier over the fire (animal fat or lard fires). This action is called: Sapponification.BC dry chemical typically does not work as well on vegetable oil fires because of the high temperature. CO2 is rated for flammable liquids, although it should be used according to the type of liquid. CO2 would be a poor choice for a hot grease fire, and is more suited for a small gasoline fire. AFFF (Foam) is an excellent choice for a wide range of liquid fires, as it has the ability to take the oxygen away, and blanket the fire with a barrier to prevent reignition. AFFF also has cooling ability. Halon and halotron are suited for class B fires, however it is a very expensive way to go, and they are usually used for delicate electronic equipment. Below are some pictures of class "B" rated fire extinguishers.
20-Pound BC Dry Chemical (Sodium bicarbonate) Extinguisher
20-Pound Purple K (Potassium Bicarbonate)
5-Pound CO2
A class"C" fire is an energized electrical fire, and usually will involve elements of a class "A" and "B" fire. Most of the extinguishers listed for use on class "B" fires will work on class "C" fires. IN NO CASE should water ever be used if electricty is a fire suspect.
Next we have class"D". Flammable metals. Usually these types of fires involve oxygen producing metals- or light metals such as: Magnesium,sodium, and titanium. The extinguisher for this type of fire is unique, in the fact that the extinguishing agent combines with the burning metal, and cancels out the oxygen. Usually the agent is salt, or it has varying degrees of fine particles of sodium. Generally a burning metal fire would be followed by foam after it is extinguished, to prevent reignition. Below is a class "D" fire extinguisher.
Class "D" Extinguisher
There are many more types of fire extinguishers, but I feel that the ones in this list are the most common. As for using a fire extinguisher, most of the ones in this list involve: Pulling the pin, aiming the hose (or nozzle) at the base of the fire, squeezing the handle, and using a side to side sweeping motion to distribute the extinguishing agent. In any case a fire extinguisher is intended to be used as a first line of defense, and when a fire is in its incipient stage. Never attempt to use a fire extinguisher if you are unsure of your safety.
