Types of fire extinguisher and their uses.
Fire extinguishers are an important part of the premises’ emergency evacuation plan. Research carried out by the Fire Industry Association has shown that portable fire extinguishers successfully extinguish a significant number of fires in the UK every year and play a major part in fire safety. Their immediate availability for use enables suitably trained persons to make a prompt attack in the early stages of a fire. As such, correctly installed and maintained fire extinguishers form an important part of the fire safety arrangements for any premises and are safe and easy to use.
Types of fire extinguisher
Because no single fire extinguisher is suitable for extinguishing every fuel class, different types of fire extinguisher have been developed. Generally, there are five different types of fire extinguisher, water, foam, dry powder, carbon dioxide and wet chemical.
Classes of fire
Appropriate types of fire extinguishers should be provided in the workplace to deal with any potential fire hazard. When deciding the types of fire extinguishers to provide, it is important to first understand the different types of fire which can occur in the workplace. Fires are classified according to the type of fuel involved. The fire classes which the fire extinguisher is safe for use on is typically represented on the body of the fire extinguisher using the symbols shown below.
Class A – Fires involving combustible solid materials.
Paper, cardboard, wood, textiles.
Class B – Fires involving flammable liquids.
Diesel, petrol, oils, paints etc.
Class C – Fires involving combustible gases.
Methane, butane, propane.
Class D – Fires involving flammable metals.
Fires involving electrical equipment.
Photocopiers, printers, monitors, computers.
Class F – Fires involving deep fat fryers.
Fire extinguisher colour codes.
The different types of fire extinguisher are colour coded to allow the operator to quickly identify the contents and fire rating of the fire extinguisher to tackle the various classes of fire. Fire extinguishers complying with BS EN3 have a signal red coloured body. This British Standard allows an area of up to 10% of the surface of the fire extinguisher body to be colour coded as shown below.
Fire extinguisher colour codes and corresponding classes of fire:
Water fire extinguishers are colour coded signal red and are suitable for use on fires involving combustible solid materials such as paper, cardboard, wood and textiles.
Note: Water conducts electricity and should not be used around electrical equipment.
Foam fire extinguishers are colour coded cream and are suitable for use on fires involving combustible solid materials as for water and also on flammable liquid fires such as diesel, petrol, oils, paints etc.
Dry powder fire extinguishers are colour coded blue and are suitable for use on multiple fire classes.
Note: However, discharging a dry powder fire extinguisher inside a building can significantly reduce visibility and cause breathing difficulties which could delay or even prevent escape. Dry powder fire extinguishers therefore, should not be specified for use indoors unless a health ans safety risk assessment has been carried out.
Carbon dioxide fire extinguishers are colour coded black and are suitable for use on fires involving electrical equipment such as photocopiers, printers, monitors, computers. They are also suitable for fires involving flammable liquid fires.
Note: For fires involving electrical equipment the power source to the electrical appliance should be cut off first, if safe to do so.
Wet chemical fire extinguishers are colour coded canary yellow and are typically provided for fires involving deep fat fryers. Some may also be fire rated for fires involving combustible solid materials.