Fire Extinguisher FAQs (Frequently Asked Questions)
We’ve put together a collection of Frequently Asked Questions FAQs about Fire Extinguishers and Fire Extinguisher Servicing. If you have a question or need further assistance with your fire extinguishers or any of our other services, please Contact Us.
|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|
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).
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.