Identifying the hazard type (A,B,C,D and K) and proper means of protecting your facility is a key element in determining the correct type of fire extinguisher for the specific hazard. It also is necessary for extinguishers to be positioned within the travel distance guidelines for the hazard and its potential severity (as stated in NFPA 10). Various types of agents are used to fight various types of fires. These include water, dry chemical, CO2, Purple K, Halotron I Clean Gas, and so on. Each of these carries a different rating and has different characteristics that are specific to the class of fire it is used to fight.