Flow moisture point

The flow moisture point is defined at IMSBC Code section 1.7 as the percentage moisture content, on a wet mass basis, at which a flow state develops under the prescribed method of test in a representative sample of the material. A flow state is separately defined as saturation to the extent that, under vibration, impaction or the ship’s motion, the mass loses its internal shear strength and behaves as a liquid.

The flow moisture point is a test result, not a carriage limit. The carriage limit is the transportable moisture limit, and only two of the six appendix 2 procedures derive it from a flow moisture point at all: the flow table test at appendix 2 paragraph 1.1 and the penetration test at paragraph 1.2, both of which set the transportable moisture limit at 90 percent of the flow moisture point under paragraph 1.1.4.4.3. The three Proctor/Fagerberg procedures read a critical moisture content off a compaction curve instead, which is why there is no general rule that the limit is 90 percent of the flow moisture point across IMSBC Group A cargoes .

The full article will cover the definition in context, the physical meaning of a flow state, the peat moss exception at 85 percent, and why quoting a flow moisture point without naming the test method that produced it is not enough to support a loading decision.