Dry freight containers, also known as ordinary containers, generally include 20GP, 40GP, 40HQ, and so on. They are usually used to transport daily necessities, textiles, handicrafts, chemical products, hardware, electronics, instruments, and machine parts. These containers have a wide range of uses and account for 70% to 80% of the total number of containers. Their structural features are often closed, with a door at one end or on the side.
Many customers may be confused as to why their cargo becomes damp when it's placed in a tightly sealed container. In fact, there's no such thing as a fully sealed container, as the container's structure determines the existence of gaps, especially near the doors. In addition, containers also have ventilation holes. The moisture in the container comes not only from the air inside, but also from the cargo itself, packaging materials (such as cardboard boxes, wooden boxes, etc.), pallets, the wooden floor of the container, and the gaps in the container. So, how can we implement effective preventive measures and protect the cargo from damage and economic losses caused by moisture?
Moisture prevention should be taken seriously in the raw material, production, and storage stages. For moisture-sensitive products, the moisture content should be used as a quality inspection standard. The humidity for packaging paper should be controlled at 5%, the humidity for inner boxes should be controlled at 10%-12%, the humidity for outer boxes should be controlled at 13%-15%, and the humidity for the wooden pallets used for storage or transportation should not exceed 20%. Suitable drying agents should be used for packaging.
The moisture absorption of different goods is different, so different packaging methods, such as boxes, bags, bundles, etc., can be used to minimize moisture damage.
Preferably, load the container on a sunny day and avoid loading during periods of high humidity in the afternoon or evening. The loading area should have a rain cover that extends at least 3 meters beyond the container to ensure a dry loading environment in any weather.
Check and ensure that the container is intact, not leaking, the container doors are functioning normally, and the locking mechanism is secure before loading the container (to confirm that the container is not leaking: during the day, go into the container and close the door to check for light; at night, go into the container, close the door, and use a high-power flashlight to check for light leakage).
In general, containers with wooden floors with a humidity of more than 20% should not be used (please use professional instruments to measure it). If the humidity of the wooden floor in a dry freight container exceeds 25%, the container should be returned, or the goods should be shipped after the container has dried. Before loading, it should be ensured that there are no residual materials from the previous batch of goods on the wooden floor of the container.
The transport environment of the dry freight container determines that the drying agent used inside the container must have a high and stable moisture absorption rate, be resistant to high temperatures, and have a long absorption time.