Types of Portable Fire Extinguishers

Class A

• Class A extinguishers are designed to extinguish items that are classified as ordinary combustibles. Ordinary combustibles are defined as any natural material such as wood, rubber and cloth. Typically, Class A extinguishers are filled with pressurized water, since these fires can be easily controlled.
  
  

Class B

• Class B extinguishers are intended to be used on flammable liquids such as refined petroleum products, greases and solvents. These fre extinguishers use either carbon dioxide or a dry chemical compound as the suppression material. This is because water will spread, rather than suppress, these liquids when they are on fire.
  
  

Class C

• Class C fires involve electrically charged appliances and tools. Since water reacts with electricity, these extinguishers use either carbon dioxide gas or a dry chemical powder as the suppression material. If it is practical to de-energize the appliance, the fire can then be treated as a Class A fire, since the electrical hazard has been mitigated.
  
  

Class D

• Flammable metals, such as magnesium and lithium, are classified as Class D fires. While these most often occur in a commercial factory settings, they can occur anywhere these metals are used, such as in motor vehicle engines or batteries. The most common suppression material found in a Class D extinguisher is dry chemical powder. These fires are also identifiable since they burn in colors other than yellow and orange, due to the particular metals.
  
  

Class K

• Class K fires are a relatively new classification that involve combustible cooking materials. These cooking fats and greases, while similar to Class B products, are typically found in commercial kitchens, where they are kept in large quantities. The amount of the material, however, does not affect its classification, since any amount of the material, when burning, would be considered a Class K fire.
  
  

Warnings

• All of these types of portable fire extinguishers are designed to extinguish a small contained fire. This means that the fire is typically confined to a single surface or container, such as a wastebasket. Before attempting to use the extinguisher, ensure you have an escape route that is not blocked by fire. Additionally, because of the weight and amount of force needed to use an extinguisher, some people may not possess the physical strength needed to safely operate one.
  
  

Multi-use Extinguishers

• Some extinguishers are capable of being used on more than one type of fire. These extinguishers will be clearly labeled so that the users will know what kinds of fires it may be used on. These portable fire extinguishers generally use a dry chemical powder as the suppression material, since it is often the least-reactive to multiple types of fire.