Last reviewed: 7 November 2026
Updated November 2026. These Grade 8 classes of fire notes explain what fire needs to burn (the fire triangle), the classes of fire, how to control each class, and the dangers of fire. A fire needs three things at once: fuel, heat and oxygen. Remove any one and the fire goes out. Fires are grouped into classes by what is burning, because the right way to put out a wood fire can make a cooking-oil or electrical fire worse.
The questions are original practice for Kenyan junior school learners, not an official paper or a substitute for fire-safety training. For other Grade 8 science topics, see the Grade 8 Integrated Science revision guide and the Grade 8 notes hub.
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What the Grade 8 Curriculum Covers
Classes of fire is a sub-strand under Mixtures, Elements and Compounds in the Kenya Institute of Curriculum Development’s Grade 8 Integrated Science design. It covers causes and classes of fire, the fire triangle, fire control by breaking the triangle and using fire extinguishers, and the dangers of fires, with a poster project on fire classes and control. The design is listed on the KICD Grade Eight curriculum designs page.
The Fire Triangle
- Fuel: anything that can burn, such as wood, paper, petrol, cooking gas or cooking oil.
- Heat: enough to raise the fuel to its ignition temperature, from a match, spark, hot surface or faulty wire.
- Oxygen: from the air.
Fire control works by breaking the triangle:
- Starving removes the fuel, for example turning off a gas cylinder or clearing dry grass to make a firebreak.
- Cooling removes heat, for example with water on burning wood.
- Smothering removes oxygen, for example with a fire blanket, sand, foam or carbon dioxide.
Classes of Fire
Kenyan textbooks commonly use the lettered classes below, which match the classes used by fire services such as Surrey Fire and Rescue’s guide to extinguishers and fire classes. Some countries, such as the USA, use different letters for some classes, so always read the label on an extinguisher.
| Class | What is burning | Examples |
|---|---|---|
| A | Ordinary solid materials | Wood, paper, cloth, plastics |
| B | Flammable liquids | Petrol, paraffin, paint, spirits |
| C | Flammable gases | Cooking gas (LPG), biogas, methane |
| D | Burning metals | Magnesium, sodium, potassium |
| Electrical | Live electrical equipment | Sockets, wiring, computers |
| F | Cooking oils and fats | Chip pan or deep fryer fires |
Controlling Each Class
The guidance below follows Warwickshire Fire and Rescue Service’s guidance on fire extinguishers, which also notes that no single extinguisher works on every class.
| Class | Suitable methods | Never use |
|---|---|---|
| A | Water, foam, dry powder | — |
| B | Foam, carbon dioxide, dry powder | Water (spreads burning liquid) |
| C | Turn off the gas supply first if safe; dry powder | Water jets on a leaking cylinder |
| D | Specialist dry powder, dry sand | Water (can react violently) |
| Electrical | Switch off power at the mains; then carbon dioxide or dry powder | Water or foam on live equipment (electric shock) |
| F | Turn off heat; wet chemical extinguisher or fire blanket | Water (causes a violent fireball) |
Using an extinguisher: PASS
Pull the pin, Aim at the base of the fire, Squeeze the handle, Sweep from side to side. Only tackle a small fire if you have a clear escape route and an adult is present. Otherwise, leave, raise the alarm and call for help.
Causes and Dangers of Fire
- Causes: unattended cooking, careless disposal of matches and cigarettes, overloaded sockets and faulty wiring, leaking gas cylinders, candles and lamps near curtains, burning of farm waste, and lightning.
- Dangers: burns and loss of life, smoke inhalation, destruction of homes, schools and property, loss of forests and wildlife, and air pollution.
Original Practice Questions With Worked Answers
- Name the three parts of the fire triangle. Fuel, heat and oxygen.
- Which class of fire involves burning petrol? Class B.
- Why should water not be used on a chip-pan fire? Water turns to steam instantly and throws burning oil out, causing a fireball.
- What should you do first in an electrical fire? Switch off the power at the mains, if safe.
- How does a fire blanket put out a fire? It smothers the fire by cutting off oxygen.
Cover the answers and attempt each question first. For timed practice, use the Grade 8 revision papers or the Grade 8 CBC Challenge. These notes are free; full revision access is available with the KSh 20 Day Pass or the KSh 500 Monthly Pass.
Frequently Asked Questions
What is the fire triangle?
The three things a fire needs: fuel, heat and oxygen. Removing any one puts the fire out.
What are the classes of fire?
Commonly A (solids), B (flammable liquids), C (gases), D (metals), electrical fires, and F (cooking oils and fats).
Which extinguisher is used for electrical fires?
Carbon dioxide or dry powder, after switching off the power if it is safe to do so.
Why is water dangerous on some fires?
It conducts electricity, spreads burning liquids, reacts with some burning metals and turns burning oil into a fireball.