Fire extinguishers are essential safety tools designed to control small fires before they spread and cause major damage. Each type of extinguisher targets a specific class of fire, ensuring that the right method is used for maximum effectiveness.
From water and foam to CO2 and wet chemical extinguishers, every variant works differently, cooling flames, cutting off oxygen, or smothering fuel sources. Understanding how these extinguishers work and choosing the right one for your environment can make a life-saving difference, whether at home, in the workplace, or in public spaces.
How Fire Extinguishers Work
Fire extinguishers are designed to stop fires by disrupting the fire triangle – a concept involving three components: oxygen in gas form, fuel or substance to burn, and a source of ignition. Extinguishers function by cutting off one element.
Removing oxygen works through equipment like foam, leaving fires starved of oxygen. Removing fuel involves turning off the gas supply or moving away flammable objects. Removing heat uses water as a liquid cooling fuel, preventing it from burning further. Using these three methods, extinguishers tackle specific categories effectively across 5 main types available today.
Types of Fire Extinguishers
Water Fire Extinguishers
Standard water fire extinguishers are used for fires involving flammable solids and remain useful in buildings like warehouses and storage facilities. Available in 3, 6, and 9 litre sizes, they work when directed at flames, the water’s extreme cooling effect lowers the temperature of material on fire.
They feature a white-coloured label stating Water and a red body for easy identification. Current guidelines recommend foam extinguishers for broader coverage, but water types excel in areas with large amounts of combustible material like paper mills and textile factories. Do not use for electrical fires, cooking fires, or flammable liquids.
Foam Fire Extinguishers
Foam extinguishers, also called AFFF foam fire extinguishers, are generally used for fires involving flammable solids and liquids. Available in 2, 3, 6, and 9 litre sizes (6 litre being most common), they’re identified by a cream-coloured label and cream body.
They work in two ways: being water-based, they lower the fire’s temperature, while aqueous film forming foam (AFFF) smothers the fire, preventing reigniting. Ideal for places with multiple fire risks like hotels, offices, garages, and factories. Use for Class A fires and some flammable liquids (Class B fires). Do not use for cooking fires or flammable gases.
Dry Powder Fire Extinguishers
Dry powder fire extinguishers, also known as dry chemical fire extinguishers or multi-purpose fire extinguishers, are incredibly versatile and used on almost every kind of fire. Available in 1, 2, 3, 6, and 9 kg sizes, they feature a blue label and blue body.
They work by smothering fires, placing a barrier between oxygen and fuel. They suppress fires very quickly but do not cool the fire, so it could reignite. Suitable indoors and outdoors for garage forecourts, commercial boiler rooms, and large workshops. Use for Class A, B, C fires, and electrical items under 1000v. Do not use in enclosed spaces.
CO2 Fire Extinguishers
CO2 fire extinguishers, or carbon dioxide fire extinguishers, are mainly used for electrical fires. Guidelines advise they’re paired with foam extinguishers for complete coverage. Identified by a black label, distinctive black nozzle, and black body, they discharge carbon dioxide stored as a liquid that converts to gas when released.
They do not cool fires; instead, they replace oxygen with carbon dioxide, making them very effective for electrical fires. Particularly recommended for offices, schools, and hospitals with lots of electrical equipment. Available in 2 and 5 kg sizes. Use for electrical fires and some flammable liquids. Do not use for Class F fires.
Wet Chemical Fire Extinguishers
Wet chemical fire extinguishers, or Class F fire extinguishers, are the only extinguisher that can be safely used for fires involving cooking oil, making them essential in professional kitchens and fast food restaurants.
They have a yellow label and yellow body, plus a longer hose than standard extinguishers. Potassium is the chemical component, which is gently sprayed to create a film over grease to suffocate the fire. Available in 2, 3, and 6 litre sizes. Excellent at extinguishing grease fires, though they produce toxic fumes, so areas must be ventilated. Use for Class F fires and Class A fires.
Clean Agent Fire Extinguishers
The final extinguisher type is termed Clean Agent, named because it uses inert gases or liquids that are non-conductive and non-volatile. These can be used on electrical fires since they do not leave any liquid behind when sprayed.
They can also be used for Class B and C fires effectively. Clean agent extinguishers are identified by a green body, green label, or green band, making them easy to recognize in emergency situations when quick identification is crucial for fire safety response.
Choosing the right Fire Extinguisher
Identification by Colour: Coding Extinguishers are identified based on coloured labels or bands on the body that indicate which classes of fire they’re used for: water (red), foam (cream), dry chemical powder ABC (blue), CO2 (black), wet chemical (yellow), clean agent (green).
Understanding Fire Extinguisher Type Classifications: With so many types of fire and fire extinguisher options, it’s important that the right extinguisher is selected when a fire breaks out. Reference the fire extinguisher type table showing extinguisher type, fire class A, fire class B, fire class C, fire class D, fire class F, and electrical compatibility.
Workplace Hazard Assessment: It’s unlikely your workplace will need every type of fire extinguisher since many are not needed in certain settings. Any organisation must consider the potential hazards of their workplace when purchasing fire extinguishers to ensure proper coverage.
Selecting Based on Specific Needs: For example, a restaurant that uses deep fat fryers will need a wet chemical extinguisher in case the fryers catch fire. A key consideration after selecting suitable fire extinguishers is ensuring they match your workplace’s specific fire risks and operational requirements.
Employee Training Requirements: Providing training to employees ensures they can use extinguishers effectively. The standard way to use them is remembered by PASS: Pull the pin from the top of the extinguisher, Aim at the base of the fire with the nozzle, Squeeze the lever to spray, Sweep from side to side across the fire to put it out.
Special Operating Instructions: Some extinguishers require more specific guidance to operate properly. For instance, foam extinguishers must be sprayed at the rear of the fire first, then spread across the fuel or substance to form a protective blanket that effectively smothers the flames and prevents reignition.
Fire Extinguishers in the Workplace
Fire extinguishers should be checked regularly in any workplace. Government guidance suggests inspections take place at least once a month to check if the extinguisher is clearly visible, not been tampered with or damaged, not been used, and still suitable for use as indicated by its pressure gauge.
Extinguishers should undergo a basic service annually, plus extended services every 5 or 10 years depending on contents. Since fire extinguishers are pressurised, it’s important when inspecting to check the pressure gauge is within the green area. Fire safety is vital – ensure correct extinguishers are located somewhere accessible. Fire safety is vital – ensure correct extinguishers are located somewhere accessible, and always complement them with a smoke alarm system for early fire detection and safety.
Conclusion
Understanding the different types of fire extinguishers and their specific uses is essential for creating a safe environment, whether at home, in offices, or industrial spaces. From water and foam extinguishers to CO2 and wet chemical types, each plays a vital role in tackling unique fire hazards effectively. Regular maintenance, staff training, and correct placement ensure quick response during emergencies, potentially saving lives and property. Don’t leave safety to chance—equip your premises with the right fire protection tools today.
Visit K Force Security or contact us to get expert guidance and certified fire safety equipment tailored to your needs.