It may be impossible for crew to estimate the particle size but they can look out for signs of high moisture content.
Appendix 3, Art 2 of the IMSBC Code states “many fine particle cargoes, if possessing a sufficiently high moisture content are liable to flow”. There are two main concerns here for seafarers relating to liquefaction. Firstly, the fine particle size of the cargo and secondly, the high moisture content, i.e. the moisture content is higher than the cargo’s transportable moisture limit (TML). The threshold for ‘fine particle’ is not defined in the Code, although the Code mentions particle size distribution in the schedule for individual cargoes. However, it may not practical for the ship’s crew to estimate the particle size of the cargo being loaded and to compare it with its IMSBC schedule. What is practical is the visual tell-tale signs of excessive moisture. As rudimentary as our recommendations on can tests and looking out for cargo splatter sounds, a vigilant crew can or could have saved several lives.
To reduce the risk of loading cargo with an excessive moisture content, shipowners, managers and crew can take some precautionary measures such as:
- Ensure documents on moisture content provided by the shipper is authentic. Inaccurate declarations and certificates from shippers still appear to be at the heart of the problem.
- Request moisture content (MC) to be tested again if there is any suspicion.
- Check the stock piles, though this may be difficult in many ports.
- Appoint surveyors during loading.
- Take advice from cargo experts.
Compilation of Gard material on liquefaction (2014)