Class A: Fires that involve carbonaceous solids like paper, fabrics, wood based products, plastics and rubbish.
Class B: Fires that involve flammable or combustible liquids. This could include chemical based cleaning products, paint, petrol, diesel, solvents and lubricants.
Class C: Fires that involve a flammable gas. Liquified petroleum gas for example.
Class D: Fires that involve a combustible metal such as magnesium, sodium, lithium, potassium etc.
Class E: Fires that involve energised electrical equipment. Switchboards, computers, amplifiers etc.
Class F: Fires that involve cooking oils or fats. Deep fryers or stove top fryers.
There is no one type of fire extinguisher that will cover all classes of fires. For this reason careful consideration needs to be given to all the factors in the fire hazard under review in order to select the most suitable fire extinguisher or combination of fire extinguishers. Where a fire including an electrical hazard can be expected the extinguishant must be electrically non-conductive in addition to having the relevant classification. The marking of E on the fire extinguisher indicates that the extinguishant as discharged is electrically non-conductive.