Variables to take into consideration Temperature
Loading
Temperature abuse affects cargoes in different ways depending on the cargo. For fresh or frozen products this might include premature ripening, freezer burn, frosting and textural changes.
To prevent this the crew should check that the container set temperature complies with the shippers’ specified carriage instructions. The external integrity of the reefer container should also be checked for damage with any defects noted and photographed. The shipper should be notified of any physical damage to the container.
Poor airflow/ventilation through the cargo can lead to temperature hotspots developing. This can be due to poor stowage or packaging of cargo preventing airflow through the cargo or over stowage of cargo preventing return air to the refrigeration unit.
Air
When carrying frozen cargo, the fresh air ventilation ducts should always be closed. In contrast, for chilled live cargoes such as fruit and vegetables the products should be stowed to allow air flow to circulate throughout the cargo stow. This will remove product heat, as well as moisture and gases such as carbon dioxide and ethylene.
The exact ventilation requirements will depend on the type of product carried.
It is important to note that the reefer container is designed to maintain the cargo temperature rather than cool it. Ideally, all cargoes should be loaded at the intended carriage temperature to ensure product quality is maintained.
The most important point for carriers is to ensure that the carriage instructions and set temperature are checked and adhered to at the time the reefer container is loaded.
Monitoring
Continuous supply of power to the reefer containers is also of utmost importance during the voyage. The vessel’s crew should regularly monitor this and ensure that all incidents regarding the vessel’s diesel generators and reefer circuit breakers and their associated alarm systems are meticulously recorded.
Proper container monitoring and prompt action during a voyage will provide helpful information as to whether the carrier should appoint a surveyor to be present for opening of the container at the destination.
Record keeping
In the event of a claim, one of the most effective defences is the maintenance of clear and accurate records and documentation of each stage of the voyage from loading through to discharge.
For reefer containers, the crew can assist by maintaining detailed and accurate monitoring and maintenance logs as well as obtaining date-stamped photographs of incidents that occur during the voyage. However, the container’s datalogger is the most accurate log available.
And here are some examples of claims that involved damage to a varied cargoes of food products.
The container vessel had loaded cargo in a European port to be discharged in Asia. Several reefer containers with meat, fish and other food had been loaded. The containers had been filled with frozen food at a temperature of -20°C and the container temperature was set to freezing.
During the voyage an AB checked the containers twice a day and logged the temperature at between -19°C and -20°C.
One month later the vessel discharged the containers in Asia. When the cargo receivers inspected the meat, they found it to be thawing. According to the container units’ records, the temperature in the containers had increased over a couple of days after departure from -15°C to +5°C. All the alarms for the containers had been disabled.
The fresh air ventilation to the containers had been open. This allowed a continuous flow of warm air into the containers. Why this had been opened after departure is not known. The cargo was fully rejected and destroyed by the cargo receivers. The crew had not verified the correct temperature of the container but only written down what should have been the correct temperature in the log as the actual container’s digital log showed +5°C and not -20°C as in the vessel’s log.
THE REPORT | DEC 2023 | ISSUE 106 | 89
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