If You Have Doubts

A powder fire extinguisher, also known as a dry chemical fire extinguisher, is highly versatile and can be used on multiple types of fires. It uses a fine powder, typically monoammonium phosphate, to suppress the fire by interrupting the chemical reaction that fuels the fire.

Key Uses:

1. Class A Fires (Solid Materials):

   • Effective on fires involving common combustibles such as wood, paper, cloth, and plastics.
   • The powder helps cool and coat the material to prevent re-ignition.

2. Class B Fires (Flammable Liquids):

   • Suitable for fires caused by liquids like petrol, oil, solvents, paints, and alcohol.
   • The powder forms a barrier that smothers the fire and prevents oxygen from reaching the fuel.

3. Class C Fires (Electrical Equipment):

   • Safe for use on electrical fires, as the powder is non-conductive, making it ideal for electrical fires in appliances, circuits, or machinery.

4. Class D Fires (Flammable Metals):

   • Some specific powder extinguishers are designed for Class D fires (e.g., magnesium, sodium, or potassium). These require a special type of dry powder, which is distinct from the general-purpose type.

Not Suitable For:

• Class F Fires (Cooking Oils and Fats): Powder extinguishers should not be used on cooking oils or fats, as they can worsen the fire or cause dangerous splattering.

Advantages:

• Versatility: Can be used for a wide range of fire types (Class A, B, C, and sometimes D).
• Quick Suppression: The powder effectively interrupts the chemical reaction that sustains the fire, quickly extinguishing it.
• Wide Application: Common in environments where different types of fire risks are present, such as factories, garages, kitchens, and industrial sites.

Disadvantages:

• Messy: The powder can create a mess and may cause damage to sensitive equipment, especially electronics.
• Limited Cooling Effect: Unlike water extinguishers, powder extinguishers do not cool the burning material, which can sometimes lead to re-ignition if not fully suppressed.

Powder fire extinguishers are usually marked with a blue label and are ideal for places where multi-type fire hazards are present. They are particularly useful in industrial settings, automotive spaces, and areas with a mix of fire risks.

Class A fires are generally caused by a naked flame or items of high temperatures coming into contact with combustible, carbonaceous materials.

Almost all premises are at risk of Class A fires due to the widespread use of such materials. This includes offices, schools, warehouses, hospitals, and anywhere that uses or contains paper, cardboard, wood, etc.

There are several types of fire extinguishers that can be used on Class A fires. These are powder, foam, water and wet chemical.

Class B fires occur when flammable liquids, such as petrol and spirits, are exposed to a source of ignition. These types of liquid are flammable by design and extremely volatile, if not stored safely.

Many settings, including restaurants, bars, garages, construction sites, laboratories, hospitals and petrol forecourts, are at particular risk of Class B fires and must keep suitable fire extinguishers on-site and mandatory fire safety signage to highlight the proper safety procedures of everyone onsite.

Fire extinguishers suitable for Class B fires are powder, CO2 and foam.

Class C Fires involve flammable gases, such as propane and butane. Flammable gases must be stored correctly in sealed containers and only operated by a competent person.

Manufacturing and industrial warehouses, chemical plants or anywhere that stores large quantities of flammable gases are at particular risk of Class C fires.

Class C fires must be tackled using a powder fire extinguisher.

Powder fire extinguishers display a blue label.