Different classification of fires and fire extinguishers.
All fires are not the same. They are divided into classes, with each class requiring a different method to extinguish and different fire extinguishers. The use of an incorrect method can actually exacerbate the situation. Let’s discuss the different classification of fires and fire extinguishers.
In the United States, fires are classified as A, B, C, D, or K.
Class A are created when ordinary combustible materials, such as wood and paper, are ignited, and can be extinguished using water or dry chemicals.
Class B involve flammable materials such as gasoline or oil and require dry chemical or carbon dioxide fire extinguishers, with water being ineffective.
Class C involve the use of electricity, and must be extinguished with dry chemicals or carbon dioxide. As was the case with Class B, water cannot be used.
The most effective treatment for Class D, which originate from combustible materials, such as sodium or magnesium, is a dry powder agent. Not only is water ineffective for Class D, it can actually create an explosion if applied.
Class K originate in the kitchen when cooking oils or fats on the stove or in the oven. Placing a lid on a pot or closing the oven door is often an effective remedy. However, special types of kitchen fire suppression systems are available for these applications.
Extinguisher colors have evolved over the years. Most of today’s Class A, B, and C extinguishers are red, with yellow being used for Class D. Kitchen extinguishers are mostly white. In the past, color codes with embedded numbers were used on labels representing three basic types of extinguishers: (1) a green triangle with an “A” inside for Class A, (2) a “B” inside a red square for Class B, and (3) a blue circle containing the letter “C” for Class C. For the most part, letters have been replaced by symbols, although color designations have largely been maintained.
It should be noted that, even though extinguishers are available to treat the various classes of fires, extreme caution should be used. Prevention is always better than mitigation. Workplaces should be equipped with fire safety equipment appropriate for the task being performed, and employees should be given in depth fire safety training. Whenever there is any doubt, though, about whether a fire can be contained, the proper course of action is to immediately vacate the premises and call 9/11.