According to data, the local production of wood charcoal and carbon for domestic and export markets is about 53 million tonnes per year. These cargoes need to comply with the IMDG Code compliance and the aim of the guide is to highlight additional precautions to enhance their safe carriage.
As explained, the most combustible matter in the charcoal is carbon, which when stored in an environment containing oxygen, slowly oxidizes to form carbon dioxide and carbon monoxide. This reaction produces heat and since Charcoal is a relatively good thermal insulator, it traps the heat, increasing both the temperature and rate of oxidation, which gives rise to self-ignition.
In some cases, charcoal bags are stored in an open space before loading with inadequate protection from rain. The recommended vanning survey should assess whether the packages have been wetted. The maximum quantity of charcoal/carbon per bag should not exceed 50 kg.
In addition, if only partially burned wood pieces are in the cargo these may give rise to the possibility of lower than required temperatures during carbonizing process, which will leave the charcoal in chemically unstable condition.
Further, it must be noted that the quality of the manufacturing process, packaging and quantity can have an impact on self-heating properties. It is recommended that, prior to carriage, carriers satisfy themselves that the cargo has been packed and secured with a method that allows safe transportation, for example, by means of a photo story or container inspection.
A vanning survey should confirm that:
– Cargo is packed and secured in a proper manner
– Packaging is water resistant, in good condition and not torn
– The temperature of the cargo when loaded is not more than 5°C above the ambient temperature
– The packaging and interior atmosphere is clean and odourless, with no presence of fumes or smoke
When a shippers’ weathering report is requested, this report should include the following:
– A description of the whole cooling process and the chemical (or steam) used for activating
– Verification that there has been a minimum of 14 days of pre-cooling prior to packaging
– It is strongly recommended that charcoal/carbon not subject to the provisions of the IMDG Code (under IMDG Code Special Provision 925) should meet the requirements for container selection, packaging, stuffing, inspection, stowage and segregation set out in guidelines below for charcoal/carbon that is classified as dangerous goods.
– It is recommended to fill the container to the maximum amount permitted in order to reduce the free space in the container and thus reduce the volume of air (oxygen). Air circulation should be reduced as much as possible.
– The cargo should be properly stowed and secured. However, packing should take account of the weight of the bags so as not to cause those at the bottom to be crushed or to split.
– The temperature of cargo prior to stuffing should not be more than 5°C above the ambient temperature.
– Prior to carriage, carriers should satisfy themselves that the cargo has been packed and secured with a method that allows safe transportation, for example, by means of a photo story or container inspection.
Click to read the guide: Guidelines-for-the-Carriage-of-Charcoal-and-Carbon-in-Containers