Flow table test for transportable moisture limit
The IMSBC Code appendix 2 paragraph 1.1 laboratory procedure that establishes a solid bulk cargo's flow moisture point on an ASTM C230-68 flow table.
The flow table test is the first of the six laboratory procedures the IMSBC Code carries at appendix 2 paragraph 1 for determining the transportable moisture limit of a solid bulk cargo. The Code states it is generally suitable for mineral concentrates or other fine material with a maximum grain size of 1 mm, and that it may also be applicable to materials with a maximum grain size up to 7 mm. The apparatus is the ASTM C230-68 standard flow table with its frame, mounting and mould.
The procedure establishes the flow moisture point, the percentage moisture content on a wet mass basis at which a flow state develops in a representative sample. Appendix 2 paragraph 1.1.4.4.3 then fixes the transportable moisture limit at 90 percent of that value. This is the source of the widely repeated but incomplete claim that the transportable moisture limit is always 90 percent of the flow moisture point: the relation belongs to this test and to the penetration test, not to the three Proctor/Fagerberg procedures.
The full article will cover the preliminary and main flow moisture tests, the apparatus tolerances, the sample preparation and the peat moss special case, in which the transportable moisture limit falls to 85 percent of the flow moisture point above a dry-basis bulk density of 90 kg/m3.