Water Isn't Always the Answer: A Guide to Extinguishing Different Types of Fires
Most people understand how to extinguish a simple camp fire - douse it with water. However, not everyone knows that there are many different types of fire and each type has a specific method of extinguishing it. Throwing a pail of water into a fire may not be the best idea when the situation calls for a different method, such as spraying foam or pouring sand on the flames. Understanding these different types of fires and learning the best ways of putting them out is important and will ensure that everyone knows how to react and stay safe in different situations.
Ordinary Combustibles (Class A)
A fire categorized as Class A burns from ordinary materials, such as paper and wood. These fires usually start when the conditions are right, such as a pile of dry wood and paper and a low breeze to fan the flames. Other types of combustible materials include clothing, rubber and plastics, which become fodder for the flames when exposed to extreme heat. Fire extinguishers containing water can easily stop the fire from spreading.
Flammable Liquids and Gases (Class B)
The second type of fire, which burns from gasoline, paint thinner, kitchen oils, propane and acetylene, requires a Class B fire extinguisher, which usually contains carbon dioxide. The use of water during these situations increases the risk of endangering human lives. Gasoline and oils float to the water's surface and continue to burn while water spills all over the place. Instead of lowering the temperature through water, cut off the fire's oxygen supply through exposure to carbon dioxide, which turns to white foam when expelled from a pressurized container.
Electrical Fires (Class C)
The use of water on a Class C electrical fire increases the risk of electrocuting survivors and firefighters. Once the main electrical line is down, use fire extinguishers labeled ABC or BC to kill Class C fires, which often start from faulty electrical equipment or torn electrical wiring. These fire extinguishers contain either carbon dioxide or dry chemical agents that stop air from fueling the flames.
Combustible Metals (Class D)
Some metals also burn hotly when exposed to heat. Fire due to reactive metals, such as potassium, sodium and magnesium, require fire extinguishers specially labeled D. These fire extinguishers usually contain sodium chloride (salt). Lithium and lithium alloy fires, on one hand, require the graphite metal-based powder in a special Class D fire extinguisher developed by the US Navy. Be aware, though, that carbon dioxide strongly reacts to these metals and may worsen the situation.
Kitchen Fires Involving Cooking Oils and Fats (Class K)
Kitchen fires are similar to Class B fires because water will not stop them. Cooking oil usually causes kitchen fires and throwing water on it will only spread the fire around the kitchen. A fire extinguisher labeled ABC or BC with either carbon dioxide or dry chemicals in it kills a kitchen fire fast. Fortunately, records from USFA indicate that the presence of fire alarms in kitchens lower the rates of death and property loss in kitchen fires.
The US Fire Administration recorded almost 400,000 structural fires, which mostly happen in residential and commercial buildings, occurred each year since 2005. These fires have caused thousands of deaths and injuries and millions of property losses, which translates to countless lives destroyed. Putting them out may not have been easy, but our valiant firefighters competently do so year after year. However, saving lives and property also involves implementation of preventive measures, such as fire extinguishers, which all home and business owners should know how to use and maintain.