Fire Extinguisher FAQs

Fire Extinguisher FAQs (Frequently Asked Questions)

Below is a collection of Frequently Asked Questions about Fire Extinguishers and Fire Extinguisher Servicing.

There are many types of fire extinguisher because there are many different types of fire. Each extinguisher is designed to be used on a specific class of fire. It is important to use the right extinguisher to ensure that your actions are as effective as possible and don’t further ignite the fire.
Class A – fires involving solid materials such as wood, paper or textiles
Class B – fires involving flammable liquids such as petrol, diesel or oils
Class C – fires involving gases
Class D – fires involving metals such as potassium or magnesium
Class E – fires involving live electrical apparatus*
Class F – fires involving cooking oils such as in deep-fat fryers
* Technically ‘Class E’ doesn’t exist. Before this classification system, there was a classification of electrical fires, but since electricity itself is a cause of fire, these types of fires have been incorporated into the main classes. Once you have turned off the electricity the fire becomes the same as any other.
Different chemicals are used for each different type of fire.

Dry chemical extinguishers use a powder-based agent which prevents chemical reactions involving heat, oxygen and fuel, this extinguishes the fire. The substances used for this are Monoammonium phosphate, sodium bicarbonate, potassium bicarbonate, potassium chloride and sodium bicarbonate based dry chemical (Foam compatible).

Foam extinguishers use an aqueous film forming foam, alcohol-resistant foams, film-forming fluoroprotein and a compressed air foam system. These smother the fires and prevent oxygen from fuelling it.

Water extinguishers use water to cool the burning material. This can be pump type water, air pressurized water and water mist

Wet chemical and water additives extinguish a fire by forming a soapy foam blanket over burning oil and cooling the oil down below its ignition temperature. They use wetting agents, antifreeze and loaded stream (an alkali metal salt solution which when added to water lowers its freezing point).

Carbon Dioxide extinguishers put out fires by displacing oxygen and removing heat from the combustion zone. They use halocarbon replacements, CO2, novec 1230, potassium aerosol and E-36 cryotec.

WATERMIST – there are no chemicals in the water mist extinguisher, it does, however, contain water. What makes water mist different or standard water extinguishers is the nozzle on the extinguisher disperses ‘dry’ water mist particles at a microscopic scale (ranging from 50 to 300µm, 50µm (micrometres) is 5/100ths of 1millimeter).
Fire extinguishers have colour codes labelling the type of extinguisher they are. These are represented on a band at the top of the extinguisher. Their purpose is to make identification easier and faster for the user. Each extinguishing medium is assigned its own colour code: Red for water, cream for foam, blue for dry power, and black for carbon dioxide. A fifth colour, yellow, is added for the new Wet Chemical type of fire extinguisher.
There aren’t any all-purpose fire extinguishers yet however, dry chemical extinguishers can be used on the majority of fires with a few exceptions.
Dry chemical extinguishers can be used on all fire except oil fires (class F fires)

Foam extinguishers are best used on combustible materials (class A) and flammable solids and liquids (class B)

Water extinguishers can only be used on combustible materials such as wood, paper, cloth, trash, and plastics (class A)

Wet chemical extinguishers can be used on combustible materials (class A) and oil fires (class F). These extinguishers have been specifically developed to tackle fires involving cooking oils and fats and contain potassium salts which both cool the flames and smother the fire’s oxygen content.

CO2 extinguishers can be used on flammable liquids (class B) and electrical fires.

Fire extinguishers with a Class C rating are suitable for fires in “live” electrical equipment. Both monoammonium phosphate and sodium bicarbonate are commonly used to fight this type of fire because of their nonconductive properties.
You should not spend more than ten seconds taking control of a fire. Do not put yourself or others at risk and always keep your means of escape behind you when tackling a small fire. Read our guide which explains how to use the different types of fire extinguishers.
Using the wrong extinguisher could make matters worse; water on an oil/electric fire would cause the fire to get bigger. It’s safer to make sure you use the correct one.
DON’T! It could cause injury due to the high pressure if you have a damaged fire extinguisher call a professional to replace it.
Fire extinguishers must be serviced every 12 months or after each use by a BAFE SP101 certified service provider. If an extinguisher is found to be leaking, it should be serviced immediately.
Fire extinguishers should be collected and disposed of in an environmentally sound way by your appointed Service Provider. A waste transfer note should be issued by your Service Provider to evidence that the extinguisher has been disposed of in accordance with regulations.