| Storage climate conditions (SC) | [German version] |
Assignment to a particular class of storage climate conditions is carried out on the basis of the requirements a cargo places upon its storage atmosphere. Depending on the classification of the product, different parameters have to be set for the risk factors temperature, humidity/moisture and ventilation to prevent a reduction in product quality. The following definitions apply:
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Goods which require particular temperature conditions: Goods which, during storage, must not exceed a maximum temperature or fall below a minimum temperature and/or which are sensitive to temperature variations. |
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Goods which require particular humidity conditions: These include goods which make particular demands of the atmospheric water vapor content and in general interact with the water vapor in the air (hygroscopic goods). With such goods, it is necessary to ensure that the relative humidity in the hold complies with certain upper or lower limits. |
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Goods which require particular air exchange rate conditions: These are goods which release substances into the atmosphere which have to be removed or which have particular requirements with regard to the composition of the atmosphere, e.g. its oxygen content, such as coal (gas extraction), respiring products (oxygen supply, CO2 and ethylene removal), oxygen-consuming products etc.. They also include goods which for particular reasons must not be ventilated. |
These three different classes of conditions may occur individually or in combination. These definitions give rise to eight groups under which the various goods may be classified in accordance with the following table. To which class a product is assigned depends, among other things, on its Water content class (WCC) and its Biotic activity (BA) (see relevant cross-references).
| Classification | Storage atmosphere requirements |
|---|---|
| SC 0 | Cargo has no particular requirements as to storage climate conditions: Dry goods which contain no water (WCC 0) and do not absorb excessive amounts of water vapor (BA 0) when stored in an outdoor atmosphere and which do not have any particular storage temperature requirements. Nor do they exude harmful substances. Examples are industrial ceramics, ceramic fittings, porcelain etc.. This group also includes goods in hermetic packaging, i.e. packaging impermeable to water vapor, irrespective of whether the goods themselves are hygroscopic, unless the type of packaging requires a different classification. These include goods which create their own gas atmosphere, e.g. mineral oils and other gas-releasing liquids in tanks. They also include numerous goods which must not be ventilated, e.g. fatty oils and fats would be damaged if oxygen were supplied (rancidity). |
| SC I | Cargo requires particular ventilation conditions: A large number of goods, which contain no water (WCC 0) and also do not interact hygroscopically with their surroundings (BA 0) and which do not have any particular storage temperature requirements, do not have any particular requirements as to temperature and humidity but do require particular ventilation conditions in order to eliminate contaminants which are detrimental to health and form explosive mixtures in conjunction with air. Examples of these are motor vehicles, the exhaust gases from which must be removed during ro-ro operation. A number of hazardous materials should also be classified in this group, since many of them generate harmful substances which have to be removed by ventilation. |
| SC II | Cargo requires particular temperature conditions: These goods may suffer damage and a reduction in utility value if the temperature exceeds or falls below certain limit values. They include goods which contain no water (WCC 0) or only a little water (WCC 1). In addition, goods with thermoplastic properties, such as resins, waxes and bitumen, become soft and tend to deform if the upper temperature limit is exceeded. If they then enter a lower temperature zone, they may become jammed. |
| SC III | Cargo requires particular temperature and ventilation conditions: This group includes goods whose requirements constitute a combination of groups SC I and SC II, i.e. they are temperature-sensitive and require the removal of harmful substances. Examples are hazardous materials, gas-releasing products and chemicals. |
| SC IV | Cargo requires particular humidity/moisture and possibly ventilation conditions: This class includes goods which contain no water (WCC 0, BA 0) and may suffer depreciation due to humidity/moisture. These include all goods at risk of corrosion, which contain no water but have a tendency to corrode if a relative humidity of 50% is exceeded, e.g. metals, metal products, machines, instruments etc.. The value of industrial glass may also be reduced by „dulling“ caused by the action of humidity/moisture. All hygroscopic goods which contain only a little water, do not respire (BA 0) and do not generate any harmful substances, likewise belong to this group, e.g. crystalline goods. These contain only a little water (WCC 1), but deliquesce after absorbing water vapor from the ambient air once the flow moisture point is reached at approximately 70% relative humidity. If they subsequently release water vapor, they solidify and become jammed. These goods include crystalline chemicals, fertilizers, salts, sugar and cement. Their sorption isotherms tend to exhibit discontinuities. |
| SC V | Cargo requires particular humidity and ventilation conditions: This group includes goods which react sensitively to moisture and in so doing generate harmful substances. Examples are hazardous materials and goods which may generate flammable gases on contact with water. |
| SC VI | Cargo requires particular temperature, humidity and possibly ventilation conditions: This group includes goods with a low water content (WCC 2), which is constantly determined by the humidity and temperature conditions of the ambient medium. The sorption isotherms for these hygroscopic goods exhibit a continuous profile without sudden jumps. Undesirable changes occur as a function of relative humidity and temperature, in particular due to dampening (mold, rot, mildew stains, fermentation, deliquescence, self-heating) or desiccation (solidification, jamming/caking, fragmentation, drying-out). The goods in this group do not have any particular requirements as to ventilation conditions, since they are dry for shipment and do not respire (BA 3), e.g. fish meal, expeller etc.. Other examples of goods in this group are foodstuffs (risk of dampening, drying-out and loss of aroma), tea, green coffee beans, raw cocoa, green tobacco (risk of post-fermentation), dried fruits (risk of syrup formation and fermentation due to effect of humidity/moisture), furs, hides, packaging materials, natural fibers and fibrous materials, wood and wooden articles, furniture and musical instruments. Ventilation may possibly be necessary, if the required temperature and relative humidity parameters are to be achieved. |
| SC VII | Cargo requires particular temperature, humidity/moisture and ventilation conditions: This group includes in particular goods with 2nd order biotic activity (BA 2), i.e. living organs, in which respiration processes (= external respiration) predominate in transit, as a result of their being cut off from the parent plant and ventilation must ensure gas exchange. Examples are goods with a water content of 1.5 – 30% (WCC 2), such as grain, legumes, oil-bearing seeds and fruits, nuts, which sometimes have a tendency towards self-heating due to their high oil content, and also goods with a water content of 70 – 90% (WCC 3), such as all easily spoiled fruit and vegetable species. Meat and fish also belong to WCC 3, being easily spoiled foodstuffs of animal origin, but they exhibit 3rd order biotic activity (BA 3) and therefore require only circulating air. |
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