Critical Moisture Content

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Graphical representation of a compaction curve produced by performing a Proctor/Fagerberg Test (PFT) on a solid bulk cargo. Source:

The Critical Moisture Content (CMC) is the point at which a graphical representation of the compaction curve of a solid bulk cargo, produced while performing the Proctor/Fagerberg Test (PFT) or the Modified Proctor/Fagerberg Test (MPFT), intersects the degree of saturation line equal to 70% or 80% depending on which test is being performed and what solid bulk cargo is being tested. This term was first used during Bengt Fagerberg's research into the PFT.[1]

Proctor/Fagerberg Test (PFT)[edit]

Appendix 2 of the International Maritime Solid Bulk Cargoes Code (IMSBC Code) states "the Transportable Moisture Limit (TML) of a cargo is taken as equal to the critical moisture content at 70% degree of saturation according to the Proctor/Fagerberg method test".[2]

Modified Proctor/Fagerberg Test (PFT)[edit]

Iron Ore Fines[edit]

The circular DSC.1/Circ.71 states "the TML of Iron Ore Fines is taken as equal to the critical moisture content at 80% degree of saturation according to the modified Proctor/Fagerberg method test".[3]


In the Modified Proctor/Fagerberg Method for Coal it states that "The critical moisture content is determined from the intersection of the compaction curve and the line S = 70% degree of saturation, with the gross water content corresponding to this intersection defined as the PFD70 value. The PFD70 value is reported as the Transportable Moisture Limit".[4]


  1. B. Fagerberg and A. Stavang, “Determination of Critical Moisture Contents in Ore Concentrates Carried in Cargo Vessels,” in Mineral Transportation, Vancouver, 1971. (Download PDF)
  2. International Maritime Organisation, International Maritime Solid Bulk Cargoes Code, 2013 Edition, London: International Maritime Organization.
  3. International Maritime Organisation, DSC.1/Circ.71 - Early Implementation of Draft Amendments to the IMSBC Code Related to the Carriage and Testing of Iron Ore Fines, 15 November 2013, London. (Download PDF)
  4. Modified Proctor/Fagerberg Method for Coal, 24 November 2014. (Download PDF)
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