What Are The Different Classes of Fire and How Should They Be Dealt With?
When selecting a fire extinguisher for your building, you will notice that there are many different types available. How do you know which one to choose? Or how many you will need? The different types of fire extinguishers are actually categorized for the class of fire they are designed to extinguish. The class of fires depends on the type of material(s) that are burning. This means that the type of business you run, as well as the equipment inside, play a role in how dangerous a fire would be, and what kind of extinguisher you will need.
While you will need to speak to your local fire department and arrange for an expert to come in and assess your needs, it’s still important that you educate yourself about the basics of fire safety.
In short, the higher the class of fire, the more powerful the extinguisher needs to be.
Class A Fires
Class A refers to ordinary combustibles, including trash, paper, cloth, rubber, cardboard, empty boxes, most plastics, etc. Essentially, it includes combustibles that leave ash. It can be generally be put out with water-mist type extinguishers. Other agents that may be used include Halotron, Halotron 1211, or foam.
Class B Fires
This class involves fires that are fueled by combustible or flammable liquid, which could be gas, oil, grease, or kerosene. The best type of extinguisher for Class B fires are ones with smother effects. When looking at extinguishers for this class of fire, there is a numerical rating that indicates the estimated number of square feet of fire it is capable of putting out.
Class C Fires
Electrical equipment is the cause of Class C fires. This includes wiring, outlets, appliances, fuse boxes, circuit breakers, etc. You obviously would NEVER want to use water-based extinguishers on an electrical fire. The C classification of a fire extinguisher means that the agent (usually carbon dioxide) is non-conductive.
Class D Fires
This classification of fire refers to those found in a chemical lab. They include combustible metals, including titanium and magnesium, shavings of combustible metals, and powders. The dry powder chemical agent that is used to deal with Class D fires is sodium chloride. Guidelines recommend that the extinguisher be placed within 75 feet from the hazard point. The sodium chloride works by smothering and absorbing heat.
Class K Fires
Class K refers to industrial or commercial kitchen fires and involves oils, grease, and fats. Installation of Class K extinguishers is required in these types of environments. Dry or wet chemical agents may be contained in the extinguisher. However, they should ONLY be used after a built-in hood suppression system is activated. If not activated, then this class of fire extinguisher is not a necessity.
About Fire Extinguisher Ratings
You’ve probably noticed that types of extinguishers can be used on more than one class of fire. Clean agent extinguishers, for instance, are for Class B and C fires. Water extinguishers, however, are for Class A fires only.
A multipurpose dry chemical can be effective on Classes A, B, and C, while the ordinary dry chemical is only for Classes B and C.
Another thing you will want to take into consideration is that fire extinguishers come in different sizes and different varieties, as some are portable. Once again, it’s important that you talk to an expert who will help you determine which size and type would be ideal for your business.