What are the classes of fire
There are six classes of fire, each requiring different fire fighting medium (extinguishers) to fight them. Modern standards mean that all extinguishers must have clear instruction labels, with a pictogram of what fire to use each extinguisher on.
The different classes of fire, and fire ratings explained:
Class A - Solid Fuel Fires
In a Class A Fire, the fire rating is decided based upon the size of a fire that can be extinguished in cubic metres, and is denoted by a number - for example 16A.
The appropriate extinguisher in the instance of a Class A Fire would be a Water Fire Extinguisher (designed to tackle Solid Fuel Fires such as wood, paper, straw, textiles, coal, etc) foam fire extinguishers and some powder extinguishers are also suitable.
Class B - Liquid Fuel Fires
For Class B Fires, the fire rating is derived from the quantity of flammable liquid that this extinguisher can comfortably put out, measured in litres, for example 32B.
The Foam Fire Extinguisher is ideally suited where both Class A and B fire risks exist. Aqueous Film Forming Foam (AFFF) is designed to fight liquid spills such as petrol, oil, fats, paints etc. by forming a film over the liquid to extinguish the fire. This extinguisher has passed the electrical conductivity test at 35kv, but not for electrical fires.
The Carbon Dioxide Fire Extinguisher is also suitable for Class B fire risks where flammable liquids and electrical problems are the most likely fire hazard. CO2 is harmless to electrical equipment, and is ideally suitable for modern offices, electrical faults and fires caused by combustion of liquids such as oils, fats, solvents.
Class C - Gas Fires
Class C Fires are very difficult to test, as flammable gas is difficult to measure with any accuracy. The fire rating is dependant on the ratio of gas to air in the local atmosphere.
The Powder Fire Extinguisher is especially designed to tackle an environment where more than one fire risk is a possibility. It is a good all round fire extinguisher as it is suitable to handle gaseous fires such as methane, propane, hydrogen, natural gas. The ABC powder fire extinguisher is efficient at tackling Class A, B and C Fires.
Class D - Metal Fires
Class D Fires are measured in cubic metres. This relates to the area of fire that the extinguisher is efficient at putting out.
The required fire extinguisher is specialist in nature and requires additional training in its use. For use on molten metal fires common in a foundry or blacksmiths.
We do not sell these online, please contact us for a telephone order.
Electrical Fires
The CO2 Fire Extinguisher is non-damaging and ideal where electrical appliances are involved in fire, until the electric has been isolated. However, as it extinguishes the fire by displacing the oxygen, it does not cool down and there is a possibility that the fire could re-ignite.
Most powder fire extinguishers can be used on electrical fires, but will render the appliance as ruined afterwards.
Class F - Cooking Oil Fires
A Class F Fire is measured in the same way as a Class B Fire. It indicates the litres of flammable liquid of 20L (cooking Oil etc) that can be comfortably extinguished using a single fire extinguisher.
Wet Chemical Fire Extinguishers are especially designed to deal with oil/deep fat fryer (or Class F) Fires. They are however, also efficient at tackling Class A Fires (wood, paper, straw, textiles, coal, etc.) This fire extinguisher has also passed the electrical conductivity test at 35kv.
The different classes of fire, and fire ratings explained:
Class A - Solid Fuel Fires
In a Class A Fire, the fire rating is decided based upon the size of a fire that can be extinguished in cubic metres, and is denoted by a number - for example 16A.
The appropriate extinguisher in the instance of a Class A Fire would be a Water Fire Extinguisher (designed to tackle Solid Fuel Fires such as wood, paper, straw, textiles, coal, etc) foam fire extinguishers and some powder extinguishers are also suitable.
Class B - Liquid Fuel Fires
For Class B Fires, the fire rating is derived from the quantity of flammable liquid that this extinguisher can comfortably put out, measured in litres, for example 32B.
The Foam Fire Extinguisher is ideally suited where both Class A and B fire risks exist. Aqueous Film Forming Foam (AFFF) is designed to fight liquid spills such as petrol, oil, fats, paints etc. by forming a film over the liquid to extinguish the fire. This extinguisher has passed the electrical conductivity test at 35kv, but not for electrical fires.
The Carbon Dioxide Fire Extinguisher is also suitable for Class B fire risks where flammable liquids and electrical problems are the most likely fire hazard. CO2 is harmless to electrical equipment, and is ideally suitable for modern offices, electrical faults and fires caused by combustion of liquids such as oils, fats, solvents.
Class C - Gas Fires
Class C Fires are very difficult to test, as flammable gas is difficult to measure with any accuracy. The fire rating is dependant on the ratio of gas to air in the local atmosphere.
The Powder Fire Extinguisher is especially designed to tackle an environment where more than one fire risk is a possibility. It is a good all round fire extinguisher as it is suitable to handle gaseous fires such as methane, propane, hydrogen, natural gas. The ABC powder fire extinguisher is efficient at tackling Class A, B and C Fires.
Class D - Metal Fires
Class D Fires are measured in cubic metres. This relates to the area of fire that the extinguisher is efficient at putting out.
The required fire extinguisher is specialist in nature and requires additional training in its use. For use on molten metal fires common in a foundry or blacksmiths.
We do not sell these online, please contact us for a telephone order.
Electrical Fires
The CO2 Fire Extinguisher is non-damaging and ideal where electrical appliances are involved in fire, until the electric has been isolated. However, as it extinguishes the fire by displacing the oxygen, it does not cool down and there is a possibility that the fire could re-ignite.
Most powder fire extinguishers can be used on electrical fires, but will render the appliance as ruined afterwards.
Class F - Cooking Oil Fires
A Class F Fire is measured in the same way as a Class B Fire. It indicates the litres of flammable liquid of 20L (cooking Oil etc) that can be comfortably extinguished using a single fire extinguisher.
Wet Chemical Fire Extinguishers are especially designed to deal with oil/deep fat fryer (or Class F) Fires. They are however, also efficient at tackling Class A Fires (wood, paper, straw, textiles, coal, etc.) This fire extinguisher has also passed the electrical conductivity test at 35kv.
