2.4: Classes of Fire
- Page ID
- 66873
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Fires are classified by the fuels that are being oxidized in the reaction.1 As a firefighter it is critical to have an understanding of each of these classes, as they also correspond to ideal extinguishing methods that can be utilized as well as hazards that may be encountered.
- Class A – Fire involving fuels comprised of ordinary combustible materials. These fuels include wood, paper, textiles and most plastics. Class A fuels are the most common fuels. Class A fuel fires are typically extinguished by cooling, or removing the heat from the reaction.
Copyright: "Dumpster fire in front of the Waldo building" by bousinka, licensed CC BY-SA 2.0.
- Class B – Fire involving flammable and combustible fluids (liquid and gaseous state) such as gasoline, diesel, propane or alcohols. Class B fires are typically extinguished by separating the oxygen from the fuel, utilizing foam.
Copyright: "LP Gas Fire Training" by Greenville, NC. Public Domain.
- Class C – Fire involving energized electrical components. This includes appliances, wiring, electrical storage systems or solar panels. Class C fires, once deenergized, are classified based on their primary fuel. Class C fires need to be extinguished using materials or techniques that do not conduct electricity, or should be deenergized before extinguishment.
Copyright: "Computer fire clipart" by j4p4n licensed CC0.
- Class D – Fire involving combustible metals. Magnesium, titanium and lithium are a few examples of these metals. Class D fires are very difficult to extinguish, often the fire is separated from oxygen or the chemical chain reaction is inhibited.
Copyright: Robert Smith, CC BY NC.
- Class K – Fire involving cooking oils, greases or fats. Class K fires are extinguished by separation of oxygen from the fuel and cooling of the fuel. Water should never be used on Class K fires.
Copyright: "A volunteer attempts to extinguish a grease fire..." by A1C Brittain Crolley. Public Domain.
| Fire Class | Fuel Type | Common Examples | Typical Extinguishment Method | Notes |
|---|---|---|---|---|
| Class A | Ordinary combustible materials | Wood, paper, textiles, most plastics | Cool the material, usually by removing the heat from the reaction | Class A is the most common type of fire. |
| Class B | Flammable and combustible fluids (liquid and gaseous states) | Gasoline, diesel, propane, alcohols | Separate the oxygen from the fuel using foam | |
| Class C | Energized electrical components | Appliances, wiring, electrical storage systems, solar panels | Use non-conductive extinguishing materials or techniques, or deenergize before extinguishment | Once deenergized, classify the fire based on the material burning, such as Class A or B. |
| Class D | Combustible metals | Magnesium, titanium, lithium | Separate the fire from oxygen or inhibit the chemical chain reaction | Class D fires are very difficult to extinguish |
| Class K | Cooking oils, greases, or fats | Cooking oils, grease, fat | Separate oxygen from the fuel and cool the fuel | Never use water on Class K fires. |
References
1. National Fire Protection Association. (2026). NFPA 10: Standard for portable fire extinguishers. https://link.nfpa.org/free-access/publications/10/2026