Fire & Electrical
By Nick Markowitz
Not the Alphabet ABC's, but the Class "A," "B," and "C" fire categories used when classifying the different types of fire extinguishers used to extinguish fires.
Class "B: extinguishers are used on fires that involve
and certain chemical fires.
Class "C" extinguishers are used on electrical fires.
Class "D" extinguishers are used on fires that involve
flammable metals, like Magnesium, Sodium, And Potassium.
When fighting a fire, it is always important to use the right extinguisher. Not doing so will either result in failure to extinguish the flames or worse, injury to yourself or someone else. For example, Never mix extinguishers and fire classes. For example, Class A extinguishers should never be used on Class C electrical fires or Class B oil fires, as immediate injury or death could result.
The older Class A extinguishers, that contain water, and the Class BC extinguishers, that contain Carbon Dioxide, can also pose a danger if the person using them is not properly trained. Both of these extinguishers are often found in older buildings within the same fire cabinet. Grab the Class A extinguisher by mistake and use it on an electrical fire and you have a deadly situation-- electrocution! Use the Class BC extinguisher next to it on a Class A-type paper fire and it will not always smother it. In addition, a Class BC extinguisher can cause severe frost burns, due to the cold Carbon Dioxide gases contained within it.
General Class ABC
Many extinguisher manufactures are steering toward an all- purpose ABC extinguisher that can be used on all three fires types without worry. Class ABC extinguishers, which can range in price from as little as $10 to over $100, usually contain a white chemical powder.
Although you do not have to worry about the type of fire when using a general-purpose, Class ABC extinguisher, there are still safety rules must be followed. For instance, avoid breathing the vapors that any of these extinguishers produce.
Another concern, as stated in previous articles in this publication, certain types of fire extinguishers should never be used as they are obsolete under NFPA, 1978 standards. This includes the old brass- and copper-type extinguishers, held together with rivets. These contain Carbon Tetrachloride, which can produce toxic Phosgene gas. Some of these old extinguishers also contain a Soda Acid propellant that can produce pressures of 300 pounds or more; under the right conditions they can explode. If you happen upon one, please take it out of service and replace it with a general-purpose, Class ABC model.
It is also important to select an extinguisher that you know is large enough to put out a fire or at least control the flames until firefighters can arrive. Consider a 2l-pound, Class ABC or larger for vehicle and kitchen use and a 10-pound unit for commercial and business applications. Remember, knowing your ABC's in an emergency can mean the difference between success and failure, safety and injury, life and death.