Fundamentals
Fire classes
Fires are classed by what is burning. The class decides what you are allowed to fight it with.
Key facts
- Class A: solid materials, usually organic (wood, paper, coal), burning with glowing embers.
- Class B: liquids (diesel oil, petrol, alcohols) and meltable solids like grease or tar.
- Class C: gases, for example methane, acetylene and hydrogen.
- Class D: metals and light metal alloys, like magnesium, sodium and aluminium.
- Class F or K: cooking oils and fats in galley equipment. It is the same class; the letter depends on the standard (F in Europe, K in the USA).
- Ignition needs fuel, oxygen and heat (the fire triangle); extinguishing means taking one of those away.
Watch out
Live electrical equipment has no class of its own. It is fought with non-conducting agents (CO2, dry powder), and the rules speak of extinguishers "with an agent suitable for electrical equipment" as an addition to the class.
Legal basis
European standard EN 2 (classes of fires); extinguisher requirements on ships: FSS Code chapter 4.
This is not a legal text: when in doubt, the current wording of the Convention and the FSS Code decides.
Related STCW training
Fire prevention and fire fighting (STCW A-VI/1-2).