Understanding Condensation

Warm air holds more moisture than cold air. As temperatures drop, relative humidity increases, and if the air cools sufficiently, condensation occurs. The dew point, the temperature at which air becomes saturated with water vapor, plays a crucial role. When the air cools further, water vapor condenses into liquid, leading to dew formation. A temperature drop of 5° is often enough to cause problems. This often happens when day shifts to night and climate zone changes.

Container Rain: A Consequence of Condensation

Container rain manifests when condensation forms on the coolest surfaces within the container, typically the ceiling or walls. This condensed water can drip onto the cargo, causing substantial damage.

Crucial Container Conditions

1. Container Airtightness: The container must be in good condition, devoid of holes or damaged doors. Ensuring this is a minimum requirement before loading. Although no container is entirely airtight, a well-maintained container significantly slows down air and moisture exchange, reducing the risk of moisture ingress. For dry cargo, it's advisable to tape the ventilation holes.

2. Moisture Content Inspection: Containers, especially those washed before loading, might contain excess water. Pay attention to the container floor, as pallets and wooden dunnage can introduce additional moisture. Goods, especially organic or hygroscopic materials, may also contain moisture. Monitoring their moisture content is essential to assess the risk.