Transportable Moisture Limit

TRANSPORTABLE MOISTURE LIMIT (TML)

Solid bulk cargoes such as metal concentrates may appear to be in a relatively dry granular state when loaded, however they may still contain sufficient moisture to become fluid under the stimulus of the compaction and vibration that occurs during a voyage. The resulting cargo shift can be sufficient to capsize the vessel.

Cargoes that contain a certain proportion of small particles and a certain amount of moisture may liquefy when the moisture content exceeds the Transportable Moisture Limit (TML). In the resulting viscous fluid state, cargo may flow to one side of the ship with a roll one way but not completely return with a roll the other way, causing the ship progressively to reach a dangerous heel and capsize suddenly.

It is therefore vital to know before loading if the material is safe to transport by ship, and to provide mariners transporting the cargo with an accurate TML and moisture content.