Understanding fire classes and which extinguisher type to use for each, so you can choose the right extinguisher and avoid making a fire worse.
Using the wrong type of fire extinguisher on a fire can make the situation dramatically worse — water on an electrical fire can electrocute you; water on a cooking oil fire creates an explosive steam reaction. Understanding fire classes and which extinguisher type addresses each is fundamental to using a fire extinguisher safely.
Different fuels burn differently and require different suppression methods:
| Class | Fuel Type | Examples |
|---|---|---|
| A | Ordinary combustibles | Wood, paper, fabric, plastics |
| B | Flammable liquids | Petrol/gasoline, diesel, cooking oil, paint |
| C (Europe/AUS: Class E) | Electrical equipment | Computers, wiring, appliances |
| D | Flammable metals | Magnesium, sodium, lithium |
| F (Europe/AUS) / K (US) | Cooking oils and fats | Deep fryers, cooking oils |
Note: European and Australian classification uses A, B, C (for gases), D, E (electrical), and F (cooking oils). US classification uses A, B, C, D, and K. The practical differences are minor — the key point is that cooking oil fires (Class F/K) require a specific wet chemical extinguisher, not standard ABC powder.
| Feature | Detail |
|---|---|
| Classes covered | A, B, C (not F/K) |
| How it works | Powder interrupts chemical chain reaction of combustion |
| Best for | General use; most common household and vehicle extinguisher |
| Limitations | Leaves damaging powder residue on electronics; poor visibility after discharge; does NOT work on cooking oil fires |
| Colour code | Blue (UK/Europe) |
The most versatile general-purpose extinguisher. Suitable for most home fires except cooking oil.
| Feature | Detail |
|---|---|
| Classes covered | B, C (electrical) |
| How it works | Displaces oxygen; reduces temperature |
| Best for | Electrical fires; computer equipment; small flammable liquid fires |
| Limitations | No cooling effect — fire can re-ignite; does not work on Class A or F/K fires; harmful in confined spaces |
| Colour code | Black (UK/Europe) |
Preferred for electrical and electronic equipment — leaves no residue.
| Feature | Detail |
|---|---|
| Classes covered | F/K (cooking oils); also A |
| How it works | Chemical reaction creates a soapy layer that seals the oil surface |
| Best for | Kitchen fires involving cooking oil and fat |
| Limitations | Expensive; specialist application; not suitable for electrical fires |
| Colour code | Yellow (UK/Europe) |
Required for any kitchen where deep frying occurs. A cooking oil fire cannot be safely managed with a standard ABC extinguisher.
| Feature | Detail |
|---|---|
| Classes covered | A only |
| How it works | Cools fuel below ignition temperature |
| Best for | Wood, paper, fabric fires |
| Limitations | NEVER use on electrical, flammable liquid, or cooking oil fires — dangerous or lethal outcomes |
| Colour code | Red (UK/Europe) |
Least versatile; highest risk if misused. Generally not recommended for households that also have other fire types.
| Feature | Detail |
|---|---|
| Classes covered | A, C (electrical) |
| How it works | Microscopic water droplets cool and suppress without conducting electricity |
| Best for | General use; electrical; safe around computers |
| Limitations | Not rated for cooking oil fires; relatively expensive |
| Colour code | White (UK/Europe) |
A modern alternative to dry powder for households — no powder residue; safer around electronics.
| Location | Recommended Type |
|---|---|
| Kitchen (no deep fryer) | Dry powder ABC + fire blanket |
| Kitchen (with deep fryer) | Wet chemical Class F/K + fire blanket |
| Living areas | Dry powder ABC or water mist |
| Garage / workshop | Dry powder ABC |
| Office / electronics | CO2 or water mist |
| Vehicle | Dry powder ABC (compact) |
A household minimum is:
⚠️ Never put water on a cooking oil fire. The water instantly vaporises and creates an explosive steam-and-oil fireball. Use a fire blanket to smother the fire, or a Class F/K wet chemical extinguisher.
| Fire Type | Use This | Never Use |
|---|---|---|
| Wood, paper, fabric (Class A) | ABC powder, water mist, water | — |
| Flammable liquid (Class B) | ABC powder, CO2 | Water |
| Electrical (Class C/E) | CO2, water mist, ABC powder | Water |
| Cooking oil (Class F/K) | Wet chemical, fire blanket | Water, CO2, ABC powder (not effective) |
| Electronics | CO2 (no residue) | ABC powder (damaging residue) |
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