In order to prevent moisture damage, it is important to understand the potential sources of moisture inside of sea containers. Sources of moisture include:

Air:

Air contains moisture in the form of water vapor, which is measured as a relative humidity percentage. Moisture content can range from 0% to 100% relative humidity. If the relative humidity reaches 100% the air will be fully saturated and there will be condensation. Warm air can contain more air than cold air. Therefore, condensation will usually first take place on the coldest available surfaces such as the container walls or ceiling.

Products:

Organic products such as food and products made of wood contain moisture. Comparatively inorganic products such as metals, machinery and glass will not contain moisture.

As organic products contain moisture, they will absorb or release moisture depending on the surrounding relative humidity until reaching an equilibrium moisture content (EMC). As inorganic products do not contain water, they will not absorb or release moisture. However, both organic and inorganic products can have moisture damage. For example, organic products can develop mold and fungus while inorganic products such as metal can develop rust and water stains.

Packaging materials:

Organic packaging materials such as wooden pallets, cartons, kraft paper etc will also contain moisture. Whereas inorganic packaging materials such as plastic pallets or stretch wrap made of plastic will not contain moisture.

Container flooring:

Most containers have flooring that is made of wood and will therefore contain moisture.

In order to prevent moisture damages in sea containers it is important to:

1) Usage of desiccants to reduce moisture and the relative humidity of the container.

2) Keep the moisture content of the packaging and container flooring below 15%.