The choices amongst fire extinguishers for sale are vast, and can be confusing. Before selecting one, many things are important to know and understand. By understanding the types of fires you are likely to face and the types of fire extinguisher available, you are much more likely to purchase one that is appropriate for your specific needs.
Types of Fires
There are five different classes of fires; A, B, C, D, and K. The substance that is burning categorizes the fire. Different substances, such as wood, liquid, gas and metal burn differently and require different things to extinguish them.
Class A fires are fires that consist of burning paper, wood, cloth or other common combustible solids. These fires are usually slow burning and can be put out by several types of fire extinguishers. Class A fires are common and can generally be extinguished by suffocation or dousing with water.
Class B fires consist of burning flammable liquids and gasses such as gasoline, propane, and common solvents. These fires are also easy to extinguish, but cannot be put out with other liquids. Liquids, such as water, can often make these fires worse by spreading the flammable liquid out and causing the fire to cover a larger area. Dry substances are used to put out these types of fires.
Class C fires consist of electrical fires. Fires involving live electrical current can be a challenge without the proper fire extinguisher. Some substances, like water, can conduct electricity, causing a risk of electrocution. Therefore, an extinguisher best puts out these fires.
Class D fires are less common and consist of burning metals. Certain metals such as magnesium and lithium are combustible, and can only be extinguished by a dry powder fire extinguisher. These fires can spread rapidly and become very difficult to put out.
The last class of fires are class K fires. These fires are most commonly kitchen fires and involve burning cooking fuels such as grease and oil. Only a wet chemical fire extinguisher can put out these fires. In the event that a fire extinguisher is not available, they can be covered in substances like baking soda, but only while they are very small.
Fire extinguishers contain a variety of substances that are specially designed to put out fires quickly and effectively. Because different substances are needed to extinguish different types of fires, they are labeled according to the types of fires they can extinguish, and are often color-coded accordingly.
Dry chemicals can be used to extinguish many common fires. Dry chemical extinguishers can usually extinguish Class A, B or C fires. Common ingredients include sodium bicarbonate, ammonium phosphate or potassium chloride. Dry chemical fire extinguishers are the most common available.
Dry powder extinguishers are used for burning metals. Combustible metals can catch on fire easily and should be stored properly. If these metals are stored or used often, a dry powder extinguisher for putting out Class D fires should always be kept available and up to date.
You will also easily be able to find a water fire extinguisher for sale, but they are only for use on class A fires. Because water can only be used on substances such as wood or paper, this type of extinguisher is most often used while camping or burning brush. Because other substances can also be used on class A fires, it may be best to purchase a more versatile extinguisher however.
Fire extinguishing foam can be used on class A or B fires. Foam is used to coat the flammable substance and starve the fire of oxygen to put it out. Some foams, like Fire-Ade, can even render the flammable material inert and prevent it from burning again. Foam is ideal for a fire that is spreading because it can be used progressively without the risk of flashback, or the fire reigniting or exploding when reintroduced to oxygen.
Wet chemicals are used for kitchen fires. Potassium acetate, carbonate, or citrate forms a foamy coating that breaks up the burning substance and then extinguishes the fire. These chemicals can break up the greasy substances that commonly cause kitchen fires. Wet chemical fire extinguishers are required in commercial kitchens due to their effectiveness.
Halogenated fire extinguishers can be used on class A, B, or C fires. This extinguisher type has been banned in Europe and can only be produced for military use in the US. Halon, the main ingredient in halogenated extinguishers, has been proven to deplete ozone and have an extended atmospheric life. While there are new types of halon being developed, these extinguishers are not recommended at this time.
Carbon dioxide extinguishers can be used on class B or C fires. These extinguishers work by displacing the oxygen that is fueling the fire and replacing it with carbon dioxide, which is not flammable. These fire extinguishers are effective, but limited to liquid, gas or electrical fires. Because of their limited ability to work on flammable solids, a dry chemical extinguisher may be a better option.
Types of Fire Extinguishers
There are two fire extinguisher types. Pressurized extinguishers contain extinguishing agents under pressure that are released when the trigger on the extinguisher is pulled. Cartridge-operated extinguishers use propellant cartridges that are punctured just prior to use to propel the extinguishing agent out.
Pressurized extinguishers are the most common type of fire extinguisher. These units are found everywhere and come in varying sizes. They can be small enough to be stored in a small cupboard or the trunk of a car or big enough to put out brush fires. Because of their versatility, pressurized fire extinguishers are easy to find and purchase.
Cartridge-operated extinguishers are most often designed for industrial use. These units are often bulky and often have wheels to move them. Because the cartridge needs to be replaced after each use, they are also more expensive to maintain.
There are many types of fire extinguishers for sale. Which extinguisher you purchase should depend on the type of fire you are likely to encounter and how big the fire is likely to be. By purchasing the fire extinguisher appropriate for your needs, you can ensure that you will be prepared in the event of a fire, and where it is safe to do so, you will be able to extinguish the fire or control it until emergency assistance arrives. One final comment. There is also the option of looking at used fire extinguishers for sale. There is a market for ex business lots that have been fully inspected and found to be in proper working order. Be very careful though to confirm the validity of the inspection process.