Fire Extinguisher Class Table
| Fuel / heat source | Europe / UK | Australia / Asia | United States |
|---|---|---|---|
| Ordinary combustibles (wood, paper) | A | A | A |
| Flammable liquids | B | B | B |
| Flammable gases | C | C | (no class) |
| Combustible metals | D | D | D |
| Electrical equipment (hazard) | unclassified | E | C |
| Cooking oil or fat | F | F | K |
| Type (AU/NZ band) | Band colour | Classes |
|---|---|---|
| Water | signal red | A |
| Wet chemical | oatmeal | A, F |
| Foam | ultramarine blue | A, B |
| Dry chemical | white | A, B, C, E |
| Dry powder (metal fires) | lime green | D |
| Carbon dioxide | black | (A), B, E |
| Halon | golden yellow | no longer produced; illegal to own or use in Australia |
Fire class letters are not an international language. The fuel is the same everywhere, but the letters wrapped around it differ by region - the sharpest edge being the letter C, which grades flammable gases in Europe and Australia while naming electrical fires in the United States, where flammable gases have no dedicated class at all. The table maps all six fuels against the three systems side by side, so an imported label, an overseas workplace or a movie prop can be read correctly instead of dangerously.
The second system hiding on every extinguisher is color. Modern cylinders are red almost everywhere - RAL 3000 red across Europe and the UK under BS EN 3, signal red in Australia and New Zealand under AS/NZS 1841 - with a small band of 5 to 10 percent of the body carrying the content code: ultramarine for foam, black for carbon dioxide, lime green for metal-fire powder, oatmeal for kitchen wet chemical. Before 1997, UK extinguishers were painted the full body color of their contents; those all-red bodies with museum-piece colors are exactly why the band exists now.
How to use
- Identify the fuel first, then read its row: wood and paper are A everywhere, oils and fats are F or K, live electrical is US-C or AU-E - the letter on the label means nothing until you know which country wrote it.
- Match the agent to the fuel, never the reverse: water is an A-only tool; foam and dry chemical cover flammable liquids; carbon dioxide and dry powder serve electrical; wet chemical is the kitchen oil specialist (F/K); metal fires demand the dedicated lime-green class D powder.
- Learn the band colors before the emergency: in smoke and darkness the 10 percent band is what you can actually read - blue foam, white powder, black CO2, green powder-for-metals - and the color table doubles as the shopping checklist for which cylinder belongs in which room.
Frequently asked questions
Why does class C mean different fires in the US and Europe?
Because the two systems grew up solving different problems and the letters never harmonized. In the American scheme, C does not describe a fuel at all - it certifies that the extinguishing agent is non-conductive and safe on live electrical equipment (the fuel behind it is usually a burning appliance or panel). In the European and Australian schemes, C grades flammable gases - propane, butane, natural gas - while electrical fires were once class E in Australia and are today unclassified in Europe: the guidance is simply to disconnect the power, after which the fire is whatever ordinary class its fuel happens to be. The practical consequence is real: a label shouting CLASS C is a gas-fire tool in London and an electrical-rating in Chicago, and the only portable way to read any extinguisher is to find the fuel in the table first and let the region column tell you the letter.
What is the difference between class F and class K?
Same fire, different initials: F is the European, UK and Australian letter for fires in cooking oils and fats, K is the American one (historically for commercial kitchens). What makes the class special is chemistry rather than fuel size - burning cooking oil behaves unlike other flammable liquids because it is stored above its own flash point in deep, hot pools, and the agent designed for it is wet chemical, which sprays a fine mist and then reacts with the oil surface to form a soapy crust (saponification) that seals and cools it. That is why kitchen extinguishers are oatmeal-banded in Australia and why the class exists as a separate letter at all: water erupts explosively in deep fat, and a generic B-rated foam or powder knocks the flames down without cooling the oil, so it re-flashes. Home cooks with a fryer or commercial-style range are the audience for an F/K unit; everyone else still needs the table to see why their ABC dry chemical says nothing about the chip pan.
What do the cylinder colors mean?
The band is the contents decoder. Australia and New Zealand (AS/NZS 1841) give every extinguisher a signal-red body with a band covering at least 10 percent of its length: signal red band = water (class A), ultramarine blue = foam (A, B), white = dry chemical powder (A, B, C, E), black = carbon dioxide (B and electrical), lime green = dry powder for combustible-metal fires (D), oatmeal = wet chemical for cooking oils (A, F), golden yellow = halon - which is no longer produced and illegal to own or use in Australia without an essential-use exemption because of ozone depletion. The UK and Europe follow BS EN 3: the whole body is red RAL 3000 and a band or circle of 5 to 10 percent of the surface names the contents. Before 1997, British bodies were painted full-color by contents - so an old all-blue water cylinder or all-black CO2 unit in a stairwell is a legacy piece to retire, not a style choice.
Can I use a water extinguisher on an electrical or oil fire?
No on both counts, for two different reasons. Water conducts electricity, so a jet aimed at live equipment makes the operator part of the circuit - electrical fires take non-conductive agents (carbon dioxide or dry powder, the black and white cylinders), ideally after the power is cut. On deep cooking oil, water is worse than useless: it sinks below the burning oil surface, flashes to steam and ejects burning oil in a fireball - the mechanism behind a large share of severe kitchen burns. Oil fires belong to the wet-chemical F/K class, which cools and crusts the surface instead of erupting through it. The one-sentence field rule the whole table compresses into: cool solids with water, smother liquids with foam or powder, starve electrical with CO2, crust kitchen oil with wet chemical, and never fight metal fires with anything but the dedicated class D powder.