Key data
| Stowage factor | 1.20–1.55 m³/t (typical 1.30)42.4–54.7 ft³/t (typical 45.9) |
|---|---|
| Form | Bulk |
| IMSBC group | A and B Cargoes that can both liquefy and carry a chemical hazard. |
| Angle of repose | ~35 |
| BCSN | COAL |
ft³/t values are per metric tonne (1 m³/t ≈ 35.31 ft³/t). Stowage factors are indicative — see note below.
Description
Coal is among the highest-volume dry bulk trades, moving from mines to power stations and industry worldwide. Its stowage factor and behaviour vary widely with rank, source and particle size, so two parcels both called 'coal' can handle quite differently. With a typical factor near 1.30 m3/t it usually fills the holds at about the point the ship reaches her deadweight, sitting close to the line between a deadweight and a measurement cargo.
Stowage & loading
Coal is loaded quickly by conveyor or grab and trimmed reasonably level to limit the surface area available for the air ingress that feeds self-heating. The cargo is kept clear of any heated structure such as fuel tanks, and bilges are confirmed clean and working so that water and the acidic liquor coal can produce are managed. The loading temperature is noted as a baseline for monitoring at sea.
Hazards & handling
Coal presents several hazards at once. It can self-heat towards spontaneous combustion, it can emit methane which forms an explosive atmosphere in enclosed spaces, and it depletes oxygen, making cargo spaces dangerous to enter. Finer coals can additionally liquefy if shipped wet. Ignition sources are excluded and the holds are treated as potentially flammable and oxygen-deficient throughout the voyage.
Carriage & discharge
Cargo and space temperatures, methane, carbon monoxide and oxygen are checked on a routine through the voyage, with surface ventilation used to clear accumulated methane while avoiding a through-draught that would feed any self-heating. A rising carbon monoxide trend is the classic early sign of heating. Discharge is by grab or unloader; spaces are ventilated, gas-freed and certified safe before anyone enters.
Key hazards
- Self-heating that can progress to spontaneous combustion within the stow
- Emission of methane, forming a flammable atmosphere in cargo and adjacent spaces
- Oxygen depletion making enclosed spaces immediately dangerous to enter
- Possible liquefaction of finer, wetter grades
Loading precautions
- Trim level to reduce the surface exposed to air and record a baseline cargo temperature
- Keep the cargo clear of heated structure and exclude all ignition sources
- Establish gas-monitoring and ventilation routines before sailing
Stowage factors are indicative and vary with grade, origin, moisture and packing. Always verify against the shipper's cargo declaration and the applicable IMSBC Code schedule before fixing or loading. This is general information, not professional or safety advice.