When most people think of a fire extinguisher, they might not realize how many different kinds of them actually exist. However, using the wrong type of fire extinguisher can be very dangerous. It is good to know as much as possible about both the fire and the fire extinguisher to avoid any preventable damage, and to maximize the results of your fire safety precautions.
There are essentially four categories of fire extinguishers. Each category is based on a particular type of fire. Numbers are used as a rating system to indicate just how much fire that extinguisher can handle. Basically, the higher the number, the greater the fire-fighting power a unit has.
Class A Fires and Fire Extinguishers
Class A fire extinguishers are for fires that result from paper, wood, cardboard, most plastics, and other normal combustible elements. In a Class A fire extinguisher, the numerical rating will represent the amount of water it contains, as well as the extent of the fire it can extinguish.
Class B Fires and Fire Extinguishers
Various combustible liquids, such as gasoline, kerosene, grease, and oil, are the source of a Class B fire. The numerical rating on a Class B fire extinguisher is referring to the size of fire it can extinguish, which is measured in square feet and is approximate.
Class C Fires and Fire Extinguishers
A Class C fire usually starts with electrical equipment. Wiring, appliances, circuit breakers, and outlets have the capacity to generate a Class C fire. One of the most important things to remember about a Class C fire is that it cannot be put out with water. If water is used on an electrical fire, there is a serious risk of shock. Class C fire extinguishers have an extinguishing agent that is non-conductive. They do not have a numerical rating.
Class D Fires and Fire Extinguishers
Mainly located in chemical laboratories, Class D fires involve combustible metals, including magnesium, titanium, potassium, and sodium. Because they are specifically intended for Class D fires only, Class D fire extinguishers will not have a rating.
Air-pressurized water (APW) extinguishers only work on Class A fires caused by ordinary combustible materials. They should never be used on grease fires, electrical fires, or Class D fires. Otherwise, the flames of the fire could grow bigger and spread further. Typically, water extinguishers are filled with water and pressurized with air.
Dry Chemical Extinguishers
Since there are some fires that feature a combination of the classifications above, chemical fire extinguishers are equipped to combat two combinations of Class A, B, and C fires:
The BC fire extinguisher is a dry chemical extinguisher filled with either sodium bicarbonate or potassium bicarbonate. When a BC fire extinguisher is used, it leaves a residue that is mildly corrosive and must be cleaned immediately to avoid damage.
The ABC fire extinguisher is also considered the “multi-purpose” dry chemical extinguisher. It is filled with monoammonium phosphate, which is a yellow powder that leaves a sticky residue. Similar to the residue left by the BC fire extinguishers, the residue from ABC fire extinguishers can cause damage, especially to computers and electrical appliances.
The Carbon Dioxide (CO2) Fire Extinguisher is used for Class B and Class C fires. Carbon dioxide is a non-flammable gas and it is highly pressurized in a CO2 fire extinguisher. In fact, the pressure has even been known to release particles of dry ice from the nozzle.
Choosing the Right Fire Extinguisher
As you can see, there are plenty of options available to you in fire extinguishers. The key to choosing the right one is to understand how it will be used. For example, CO2 fire extinguishers are not very effective on Class A fires, and the insufficient oxygen might reignite the fire.
Dry chemical fire extinguishers do leave a substance on whatever has been extinguished, but it is non-flammable and might reduce the risk of re-ignition. And CO2 fire extinguishers do not leave any harmful residues; excellent for electrical fires on or near a computer or other valued equipment. Different rooms may require different types of fire extinguishers, depending on what is in the room. Look at the materials and items in a room to determine which extinguisher is appropriate.
Overall, if you are not sure of which fire extinguisher to purchase, check with an expert or fire marshal. To make sure that your fire extinguishers are located in the correct places and are compliant with the British Columbia fire codes in your area, please contact GetFirePlan.com. You can schedule a free consultation by calling (778) 574-2895 or with the form below.