Common problems associated with the transportation of coal in bulk include self-heating and methane production. Self-heating can lead to fires, and the production of carbon monoxide (CO) and methane lead to an explosive atmosphere being generated in a hold. From our experience with coal cargoes loaded in Indonesia, self-heating is a frequently encountered problem.
Hawkins regularly deal with problems associated with self-heating coal cargoes. For example, following loading of a cargo, the vessel begins to monitor the hold atmosphere and notes very high carbon monoxide levels. We can assist by attending in order to determine the actual situation or provide advice on how to avoid problems associated with self-heating coal becoming a major issue. Below is advice on the loading of coal cargo and actions the Master can take.
The IMSBC Code provides mandatory requirements for the loading and carriage of coal. Of particular note are the following:
Drager X-am 7000 used in the detection of gases and vapours
Self-heating normally occurs in localized hot spots within a bulk cargo, and temperature measurements are unlikely to identify any problems. However, when coal self-heats it produces CO, so measuring the concentration of CO is the most effective method to identify a self-heating cargo. The atmosphere in each cargo hold should be monitored, at least on a daily basis, for CO, oxygen, hydrogen sulphide and flammable gas (LEL). If the holds are being ventilated, then ventilation should be stopped at least 4 hours prior to gas measurements being taken.
If there is a fire or high levels of CO are detected, the vessel should:
Despite the risks associated with the transportation of coal cargoes, the majority of vessels carry them without incident, and adhering to the requirements and recommendations in the IMSBC Code greatly reduces the risk of fire. Hawkins have many years of experience in assisting Owners and P&I Clubs preventing an incident from becoming a major casualty. If the Master only allows cargo below 55˚C to be loaded and regularly checks the cargo, then problems can be identified at an early stage and thereby prevented from escalating.
Dr John Allum has investigated a wide variety of marine incidents on ships and yachts, including fires on bulk cargo vessels, container ships and tankers. He has provided advice on 'live' ship fires involving cargoes such as DRI, coal and agricultural products.