The term “risk factors” refers to the characteristics of transport technology that the consignor should take into account when preparing for the transport of goods in order to minimize or exclude potential risks from the outset.
Therefore, all technological processes require information to be provided in a form suitable for the application in order to control and optimize them. The information required for the transport, transshipment and storage processes in the transport system must also be available as completely as possible.
The following risk factors are taken into account in the commodity information:
- Biotic activity
- Mechanical influences
- Toxicity/Hazard to health
- Pest infestation/diseases
Risk factor temperature
Most goods may change adversely under the influence of temperature, i. e. they may suffer quality reductions/damages. This is why we speak of the temperature sensitivity of the goods.
The more optimally the temperatures in the container can be adapted to the requirements of the goods, the better their quality can be maintained.
Travel or transport temperature
In general, the travel or transport temperature is the optimum storage temperature of a product that should be aimed at in order to achieve maximum shelf life. For most non-temperature controlled goods, temperature ranges of 5-20 °C as optimal.
However, higher temperatures are to be expected on journeys to the subtropics and tropics and cooler temperatures in the temperate latitudes in the winter months.
Basically, the information about the optimal temperature range is helpful because it shows that a transport always entails a certain danger.
Upper and lower limits of the travel temperature
If the upper temperature limit is exceeded, fruits and vegetables, for example, can suffer considerable deterioration in quality and damage as a result of intensified enzymatic and microbiological processes. Increased temperatures can also lead to self-heating or cargo firing of goods containing oil. Exceeding the upper temperature limit results in drying out, breakage and pulverisation of raw tobacco, for example.
Therefore, it is important to avoid the proximity of heat sources, e. g. tank ceilings, engine room bulkheads. If the temperature falls below the lower temperature limit, for example, cold storage damage (chilling) is to be expected for fruit species and ice blasting is to be expected for beverages and water-containing preserves.
Due to temperature changes when passing through different climatic zones, there may be a softening and melting as well as subsequent hardening and blocking, e. g. with natural rubber, bitumen, gums and resins (Japanese wax, paraffin, shellac). When the containers are unloaded, the blocked natural rubber bales can tear.
The above examples show that many goods cannot survive transport without controlled temperatures: they must either be heated, such as many sweetening oils, or they must be chilled or frozen for perishable goods. This is referred to as temperature-controlled transport.
Temperature-controlled transport by heating
By cooling down, sweet oil approaches its solidification point and it becomes ointment and finally solid. One speaks of the cold cloudiness (segregation). This segregation and the associated change in consistency occurs the higher the solidification point of the sweet oils is. Sweet oils to be transported in heatable tank containers require certain loading, travel and pumping temperatures. For example, palm oil:
Solidification range 24-19 °C
Charging temperature 35 °C
Travel temperature > 24 °C
Pumping temperature 50-55 °C
Temperature-controlled transports through cooling and/or freezing
The transport of perishable foodstuffs with high water content and high biotic activity is carried out in refrigerated containers, where the desired loading, travel and unloading temperatures are achieved by means of refrigeration units.
Loss prevention advice
Exceeding the upper temperature limit has, for example, led to bombing of canned food and hot blasts of non-alcoholic beverages (especially in glass bottles). Thermal bombs are most often seen in the area of the container ceiling. It is therefore recommended that the standard containers are stowed below deck and not near heat sources.
If the temperature falls below the lower temperature limit, the same groups of goods can be iced, and it is also recommended that the containers are stowed below deck during the winter months.
If ventilated containers are used, e. g. in the winter months for transporting green coffee (travelling from warm to cold), the ventilation in the hold must be reduced so as not to supply too much cold air, which can cause condensation water to form when the dew point is fallen below.
Damage caused by temperature fluctuations during the voyage leads to blocking of crystalline goods, e. g. during sugar transport. That is why transport in double sacks (outer jute, inner plastic) has proven its worth.
In the event of temperature fluctuations, e. g. when travelling from cold to warm in the winter months, it is advisable to load particularly cost-intensive goods, such as high-quality machines, precision instruments, etc., into refrigerated containers that do not require connection. The thermally insulated walls of the refrigerated containers do not cause high temperature fluctuations, which would cause the temperature to fall below the dew point, and the formation of sweat and corrosion can be prevented.
Especially in the cold season, it is necessary to unload (stripping) the containers at the port of destination, e. g. for green coffee and raw cocoa. Coming out of the relatively sheltered environment of the ship’s cargo hold, one can still count on a core temperature of 18-20 °C for coffee loads.
If they are now exposed to the much lower outside temperature, the result is a rapid increase in humidity in the containers. Condensation on the container ceiling and walls causes unavoidable damage to the cargo caused by moisture.
In summary, it can be said that the temperature sensitivity of the goods can be assessed very differently. If there is a risk of ice blasting or chilling, for example, the cargo must be transported at a controlled temperature. If the consequences of exceeding or falling below the temperature limits are rather minor, it must be decided in individual cases whether the risk can be taken. The product information provides a good decision-making aid.