What Do the Symbols on a Fire Extinguisher Indicate?

Living in a high-rise environment like Singapore, fire safety is not just a personal responsibility but a community one. Whether you are in an HDB flat, a private condominium, or a commercial office in the CBD, the sight of a red canister in the corridor is familiar. However, simply having one nearby is not enough. If a fire breaks out, you need to know exactly what that canister can do.

The symbols on a fire extinguisher are a universal language, but they are also strictly regulated in Singapore under the SS 578 standard. Understanding these labels is a core part of any comprehensive fire safety in Singapore for residents and business owners alike.

The Importance of Fire Classification in Singapore

In Singapore, the SCDF categorises fires based on their fuel source. Using the wrong extinguisher can be disastrous. For instance, using water on a burning frying pan in a hawker centre or a home kitchen will cause a massive fireball.

By familiarising yourself with these symbols during a fire risk assessment, you ensure that you are prepared for the specific risks in your environment, whether it is a server room filled with electronics or a warehouse storing wooden pallets.

Understanding the Primary Fire Class Symbols

On any SCDF-approved extinguisher, you will see specific pictograms. These usually consist of a letter and an image representing the fuel. Here is the breakdown of what those symbols indicate:

Class A: Ordinary Combustibles

The Class A symbol features a pictogram of burning rubbish, wood, or paper.

• What it means: This extinguisher is designed for organic solids such as paper, wood, cloth, and plastics.
• Commonly found in: Residential corridors, HDB lift lobbies, and general office areas. A water fire extinguisher or a foam unit is typically used here.

Class B: Flammable Liquids

The Class B symbol shows a fuel container pouring liquid onto a fire.

• What it means: This indicates the unit is suitable for flammable liquids like petrol, oil, thinners, and paints.
• Commonly found in: Car parks, workshops, and industrial estates in Jurong or Tuas where hazardous substance storage is common.

Class C: Flammable Gases

Class C is represented by a pictogram of a gas cylinder with a flame.

• What it means: This is for fires involving gases such as LPG (common in some older kitchens) or town gas. In Singapore, it is vital to shut off the gas supply before attempting to extinguish the flame.
• Commonly found in: Kitchens and gas meter rooms.

Class D: Combustible Metals

The Class D symbol features a gear or metal shard on fire.

• What it means: This is for specialist fires involving metals like magnesium or titanium. Water must never be used on these fires as it can lead to an explosion.
• Commonly found in: Specialist manufacturing plants or chemistry laboratories.

Electrical Equipment: The Lightning Bolt

Under Singapore standards, electricity is a source of ignition rather than a class of fuel. However, it is marked with a blue lightning bolt or a picture of a plug on fire.

• What it means: This confirms the extinguisher is non-conductive and safe for use on live electrical equipment. A CO2 fire extinguisher is the gold standard here as it leaves no residue on sensitive circuit boards.
• Commonly found in: Server rooms, data centres, and near electrical distribution boards (DB boxes).

Class F: Cooking Oils and Fats

The Class F symbol shows a frying pan on fire. (Note: This is sometimes referred to as Class K in American systems, but Singapore uses Class F).

• What it means: This is specifically for high-temperature cooking oils and fats. Standard extinguishers cannot cool the oil enough to stop it from re-igniting.
• Commonly found in: Hawker centres, commercial kitchens, and residential kitchens.

The “Prohibition” Symbols: What Not to Do

One of the most important things a Singaporean consumer can look for is the symbol with a red diagonal line through it. This is a prohibition sign.

If you see a red circle with a line through a lightning bolt, it means the extinguisher is water-based and conductive. Using it on an electrical fire could result in a fatal shock. Checking for these negative indicators is a mandatory part of fire safety training for employees in Singapore.

Colour Coding Standards (SS 578)

While the symbols provide the detail, the colour-coded band allows for instant identification from a distance. In line with internationally influenced standards, all SCDF-compliant extinguishers are red, with a specific colour band:

• All Red: Water (Class A only). 
• Cream Band: Foam (Class A and B).
• Blue Band: Dry Powder (Class A, B, and C).
• Black Band: Carbon Dioxide (Electrical and Class B).
• Yellow Band: Wet Chemical (Class F).