About Container Desiccant

What Type Of Container Desiccant Can Meet The Needs Of Sea Cargo Shipping.

Q: Why do import and Export Sea Shipments Get Damp?

A: The primary cause of dampness in sea shipments is temperature variation, which triggers condensation inside the container.

Warm air holds significantly more moisture than cold air. For example, at 40°C, a single cubic meter of air can hold up to 51.2 grams of water vapor. However, if the temperature drops to 20°C, that same air can only hold about 17.3 grams. The excess 33.9 grams condenses into liquid water—the same natural process that creates summer dew or autumn frost.

Because shipping containers are sealed, enclosed spaces, they are highly vulnerable to this process during ocean transit. When external weather causes the temperature inside the container to drop sharply, the trapped, moisture-heavy air has nowhere to escape. It condenses on the ceiling and walls, eventually dripping down onto the cargo in a phenomenon known in the logistics industry as "container rain."

In addition to the air itself, moisture can also be released from:

• Wooden pallets and container flooring

• The cargo itself (especially organic goods or hygroscopic materials)

Once this damp environment forms, goods become highly susceptible to mold, deterioration, and rust, ultimately leading to severe cargo damage.

Q: How Do Container Desiccants Prevent Cargo Dampness?

A: Container desiccants start absorbing moisture from the air inside the container from the moment they are installed. When used in adequate amounts, they help maintain optimal humidity levels inside the container. This ensures that even if temperatures drop suddenly, there won’t be excess moisture in the air to condense. As a result, “container rain” is avoided, and goods remain in a dry and safe environment throughout the shipping process until unloading.