Due to the various classes of fire (A, B, C, D and K), it is necessary to provide the correct type of fire extinguisher for the site-specific hazard. It is also necessary for extinguishers to be positioned within the travel distance guidelines for the hazard and its potential severity. Various types of agents are used to fight specific types of fires. These include water, dry chemicals, CO₂, Purple K, Metal-X, FE36, etc. Each of these carries a different rating and has different characteristics that are specific to the class of fire it is used to protect.
Following is a description of the various fire class types: