Fire Classes Explained: A, B, C, D, and F/K
Plain-English guide to the 5 main fire classes \u2014 what they are, how they behave, and exactly which extinguisher type to use for each.
There are 5 main fire classes: A (paper, wood, cloth), B (flammable liquids like petrol or alcohol), C (electrical equipment), D (combustible metals \u2014 rare in homes), and F/K (cooking oils and fats). Most home fires are Class A or F/K. The wrong extinguisher on the wrong class can make a fire dramatically worse, which is why a multi-class compact extinguisher like the LifeSafe StaySafe All-in-1 is what most homes actually need.
Why Fire Classes Matter (And Why The Wrong One Costs You Your House)
Fires aren't all the same. A pan of burning olive oil behaves differently from a smouldering laptop battery, which behaves differently from a flaming bin of paper. Different fires need different suppression methods — and using the wrong method doesn't just fail to put out the fire. It often makes it dramatically worse.
That's why the global fire safety community categorises fires into classes — letters that tell you what's burning, how it behaves, and which extinguisher type will actually stop it. Understanding these classes is the difference between a contained kitchen incident and a complete loss of your home.
You don't need to memorise the chemistry. You just need to know which classes apply to your home, which extinguisher you currently own, and whether they match. Most homes have a mismatch — and most homeowners don't realise it until it's too late.
The 5 Fire Classes Explained
Class A: Ordinary Combustibles
What it is
Paper, wood, cloth, plastic, rubber, household trash. The most common fire in homes.
How it behaves
Smoulders before flaming. Spreads via dry materials. Generally easy to suppress in early stage.
What to use
Water, foam, dry powder, or a multi-class extinguisher rated for A.
What NOT to use
CO₂ extinguishers — they don't cool effectively and the fire will reignite from embers.
Class B: Flammable Liquids
What it is
Petrol, diesel, alcohol, paint thinners, kerosene, lighter fluid. Anything liquid that burns.
How it behaves
Spreads fast across surfaces. Vapours can ignite from sparks across a room. Can flash back after suppression.
What to use
Foam, dry powder, CO₂, or a multi-class extinguisher rated for B.
What NOT to use
Water — it spreads burning liquid and intensifies the fire.
Class C: Electrical Fires
What it is
Live electrical equipment — outlets, wiring, appliances, computers, EV charging cables.
How it behaves
Often invisible at first (smoke from inside an appliance). Can electrocute anyone using a conductive extinguisher.
What to use
CO₂, dry powder, or a non-conductive multi-class extinguisher rated for C and electrical safety up to a known voltage.
What NOT to use
Water or foam on live circuits — both conduct electricity and can electrocute the user.
Class D: Combustible Metals
What it is
Magnesium, sodium, titanium, lithium metal. Rare in homes but found in some industrial settings and certain laboratory equipment.
How it behaves
Burns at extreme temperatures. Reacts violently with water. Specialised fire — most home extinguishers are not rated for it.
What to use
Specialised Class D dry powder only. Not covered by typical home extinguishers.
What NOT to use
Water (explosive reaction), foam, CO₂ — all ineffective or dangerous on Class D.
Class F/K: Cooking Oils & Fats
What it is
Hot cooking oil, animal fats, deep-fryer fires. Burns hotter than other liquid fires.
How it behaves
Reignites easily even after appearing extinguished. Water creates fireballs. Most dangerous home fire class for the average cook.
What to use
Wet chemical extinguishers, fire blankets for very small flames, or a multi-class extinguisher rated for F/K like the LifeSafe StaySafe All-in-1.
What NOT to use
Water (creates fireball), flour (can explode), or standard ABC dry powder (spreads burning oil).
What Class Of Fire Is Most Likely In Your Home?
Kitchen
Most likely: Class F/K (cooking oil), Class A (towels, paper). Less common: Class B (cleaning solvents), Class C (appliances). Recommended: Multi-class extinguisher rated for at minimum A, B, C, and F/K. Store within 6 feet of stove.
Living Room
Most likely: Class A (furniture, fabrics). Less common: Class C (electronics, lithium-ion in phones/laptops). Recommended: Multi-class A/B/C/lithium-ion-rated unit near charging stations.
Garage / Workshop
Most likely: Class B (fuel, solvents), Class C (power tools). Less common: Class A (sawdust, rags), lithium-ion (tool batteries). Recommended: Multi-class A/B/C/lithium-ion-rated unit, plus a larger Class B-specific canister for fuel storage areas.
Garage With EV
Most likely: Class C (charging cable shorts), lithium-ion (battery thermal events). Less common: Class A, B. Recommended: A multi-class compact unit specifically rated for electrical above 1,000V and lithium-ion thermal runaway.
Bedroom
Most likely: Class A (bedding, furniture), lithium-ion (charging phones, laptops). Less common: Class B, C. Recommended: Compact multi-class unit accessible from bed-side. Especially critical near charging points.
Bathroom
Most likely: Class A, Class C (hairdryers, electric toothbrushes). Less common: Class B (aerosol cans). Recommended: Compact multi-class unit. Important for older homes with degraded electrical systems.
What We Recommend For Most Homes
Most homes don't need a different extinguisher per room. They need one or two multi-class compact units placed strategically. After testing 14 small fire extinguishers across all 5 fire classes, the LifeSafe StaySafe All-in-1 covers the four classes that matter for homes — A, B, C, and F/K — plus lithium-ion battery fires, in a single 9-oz aerosol unit.
For Class D fires (rare in homes), you'll need a specialised industrial Class D extinguisher — but unless you store magnesium or work with specific metals, you don't need one.
Our Top Multi-Class Pick
The LifeSafe StaySafe All-in-1 covers A, B, C, F/K, and lithium-ion fires in a 9-oz compact format.
Frequently Asked Questions
Know Your Fire Class. Get The Right Extinguisher.
Most home fires are Class A or F/K. The StaySafe All-in-1 covers both \u2014 plus B, C, and lithium-ion \u2014 in a single 9-oz canister for $29.99.