While professional firefighters are always the ultimate line of defence, a correctly chosen and well-maintained fire extinguisher can tackle a small blaze before it escalates, protecting lives and property. But with different types of fires and a variety of extinguishers available, how do you know which one is right for the job?

This guide will walk you through the different classes of fire, the types of fire extinguishers designed to combat them, and how to make the best choice for your specific environment. It's about empowering you with the knowledge to react swiftly and effectively if a small fire takes hold.

Understanding the Classes of Fire

Fires are categorised into different classes based on the type of fuel involved. This classification is crucial because it dictates which extinguishing agent will be effective and safe to use. Using the wrong type of extinguisher can not only be ineffective but also incredibly dangerous.

Class A Fires: Ordinary Combustibles

Class A fires involve common combustible materials such as wood, paper, textiles, and plastics. Think of a wastepaper bin fire in an office or a pile of cardboard boxes in a warehouse. These fires produce ash and typically leave behind glowing embers.

Class B Fires: Flammable Liquids

Class B fires involve flammable liquids like petrol, oil, grease, paint, and solvents. These fires spread rapidly and produce intense heat. A spillage in a workshop or a kitchen oil fire are examples of Class B hazards.

Class C Fires: Flammable Gases

Class C fires involve flammable gases such as propane, butane, and natural gas. These fires are particularly hazardous because a gas leak can lead to an explosion. A faulty gas heater or a ruptured gas line are examples of Class C risks. It's important to turn off the gas supply before attempting to extinguish a Class C fire.

Class D Fires: Combustible Metals

Class D fires are less common in general workplaces but are a significant risk in industrial settings. They involve combustible metals such as magnesium, titanium, potassium, and sodium. These fires react violently with water and require specialised extinguishing agents.

Electrical Fires (formerly Class E)

While electrical fires used to be classified as "Class E," they are now generally considered a subcategory of other fire classes, as the fuel source itself is what dictates the class once the electricity is turned off. However, the presence of live electrical equipment means that the extinguishing agent used must be non-conductive to prevent electrocution.

Class F Fires: Cooking Oils and Fats

Class F fires involve cooking oils and fats, typically found in kitchens. These fires burn at very high temperatures and traditional water-based extinguishers can cause the fire to spread rapidly. This is a very specific hazard that requires a particular type of extinguisher.

Matching Extinguishers to Fire Classes

Once you understand the different fire classes, you can then match them to the appropriate fire extinguishers. Each extinguisher type contains a specific agent designed to combat certain types of fires safely and effectively.

Water Extinguishers

Water extinguishers are suitable for Class A fires only. They work by cooling the burning material, removing the heat element of the fire triangle. They are not suitable for Class B, C, D, or F fires, and can be dangerous if used on electrical fires.

Foam Extinguishers (AFFF)

Foam (AFFF - Aqueous Film Forming Foam) extinguishers are versatile and effective on Class A and Class B fires. The foam creates a blanket over the burning liquid, cutting off the oxygen supply and cooling the fuel. They are safe for use where electrical equipment might be present, but care should be taken.

CO2 Extinguishers (Carbon Dioxide)

CO2 extinguishers are primarily used for electrical fires and Class B fires. They work by displacing oxygen, suffocating the flames. Since carbon dioxide is a non-conductive gas, it's safe for use on live electrical equipment. They leave no residue, making them ideal for sensitive equipment.

Dry Powder Extinguishers (ABC/BC)

Dry powder extinguishers are multi-purpose, suitable for Class A, B, and C fires. Some specialised dry powder extinguishers are also available for Class D fires. They work by smothering the fire and interrupting the chemical reaction. However, they can create a mess and impair visibility, and are not recommended for use in enclosed spaces where people are present due to potential inhalation issues.

Wet Chemical Extinguishers

Wet chemical extinguishers are specifically designed for Class F fires involving cooking oils and fats. The chemical creates a non-combustible soap-like film over the burning oil, cooling it and preventing re-ignition. They can also be used on Class A fires.

Specialist Extinguishers

For Class D fires, specific dry powder extinguishers are needed, often containing agents like sodium chloride or graphite. These are highly specialised and should only be used by trained personnel.

Choosing the Right Extinguisher for Your Workplace

Selecting the correct fire extinguishers for your workplace involves a thorough assessment of the potential fire hazards present. This is where your fire risk assessment comes into play. The responsible person for fire safety in your building should identify the types of combustible materials and ignition sources.

Consider the following steps:

Identify Fire Classes Present: Walk through your premises and identify the potential fuels. Is there paper and wood (Class A)? Are there flammable liquids like cleaning solvents or fuels (Class B)? Do you use gas appliances (Class C)? Do you have a commercial kitchen (Class F)?

Assess the Risk Level: How likely is a fire involving each class of material? What are the potential consequences?

Consult Regulations: Ensure you comply with relevant UK fire safety regulations and British Standards, such as BS 5306, which guides the selection and installation of portable fire extinguishers.

Placement and Accessibility: Extinguishers should be strategically placed near potential hazards, clearly visible, and easily accessible. They should not be blocked by furniture or equipment.

Staff Training: Even with the right extinguishers, they are ineffective if staff don't know how to use them. Comprehensive training on the different types of extinguishers and their appropriate use is essential.

Maintenance and Servicing

Having the right fire extinguishers is only half the battle; they must be regularly inspected and maintained to ensure they are always ready for use. Fire extinguisher maintenance and servicing is crucial.

Monthly Visual Checks: A designated person should conduct monthly visual checks to ensure the extinguisher is in its correct place, visible, unobstructed, and that the pressure gauge (if applicable) is in the green zone. The tamper seal should be intact.

Annual Professional Servicing: A qualified technician should carry out an annual inspection and service of all fire extinguishers. This involves a more detailed check of all components, refilling if necessary, and ensuring compliance with industry standards.

Extended Servicing: Every 5-10 years, depending on the type, extinguishers will require an extended service, which may involve a test discharge and refill.

At Magni Fire, we not only help you choose the right fire extinguishers for your specific hazards but also provide comprehensive maintenance and servicing to ensure they are always in perfect working order. Our expert team understands the nuances of different environments and can offer tailored advice to keep your premises safe.

Choosing the right fire extinguisher is a vital part of your overall fire safety strategy. By understanding fire classes and the capabilities of different extinguishers, you empower your workplace with the tools to prevent a small incident from becoming a major disaster. A proactive approach to fire safety, combining correct equipment with regular maintenance and thorough staff training, builds a truly secure environment.

Unsure about the fire extinguishers needed for your business? Contact Magni Fire today to speak with our experts and ensure your workplace is fully protected.