Sources of Moisture

  Cargo Sweat

  Container Sweat

  Heat Radiation

 Definitions

The risk of condensation damage during a voyage is very real, especially in general purpose containers. in serious cases this leads to huge losses and resultant claims.

The following section highlights the problems associated with condensation and also identifies the main sources of condensation during a voyage.

Container Sweat

Container Sweat occurs when the skin of the container is cooled to a temperature below that of the dew point of the air in the container. The water vapour condenses on the inside surfaces of the container when moving from tropical or temperate climates to cooler regions.

Container sweat results in water droplets forming on the interior roof and side panels, then dripping down on the cargo causing mould and water damage. Cargo that spontaneously heats from within can increase the problem.

For example:

Cargo loaded in the tropical belt in warm conditions with high Relative Humidity, is transported to cold winter conditions in Europe. During the voyage the temperature outside the container gradually dropsThis drop in temperature gradually gets transferred to the inside of the container which contains relatively warm air. When the dew point of the trapped air is reached, condensation takes place inside the container and this condensation will continue until the dew point of the interior air is equal to that of the outside air.