Why do container side walls bulge during liquid transportation?
During liquid transportation, especially when using flexitank, sidewall bulging is a common occurrence. However, this is not caused by the flexitank but by different external factors.
Container sidewall bulging is usually related to loading, the structural condition of the container and external factors. To minimize such problems, proper container selection, careful loading procedures and regular quality checks are of paramount importance.
- Structural Strength of the Container
Standard sea containers are generally designed to carry dry cargo. The side walls of these containers may not be sufficiently resistant to the pressure generated during bulk liquid transportation. In old or previously damaged containers, fluid movements during transportation can lead to deformation.
- Container Metal Fatigue
Containers can experience metal fatigue in long-term use with different types of loads. Containers that have been overloaded or carried heavy equipment in previous shipments are at risk of structural deformation. When flexitank is used in such containers, the possibility of side walls bulging increases.
- Temperature and Weather Conditions
Extremely hot or cold weather conditions can cause metal containers to expand or contract. Temperature changes, especially in containers for liquid transportation, may cause flexing of the side walls and a slightly curved appearance. - Transportation and Stacking Conditions
Containers are stacked on top of each other on ships, in ports or in land transportation. The weight of the top container can put pressure on the walls of the bottom container, causing it to deform over time. Low-quality or old containers are particularly susceptible to this pressure.
5. Previous Damage to the Container
Containers that have previously been subjected to improper forklift handling, bumps or impacts can become unstable to internal pressure. The absence of visible damage prior to loading does not necessarily mean that the container is structurally sound. Previously weakened side walls become even more pronounced under the internal pressure of the liquid.
For these reasons, it is important to carry out a detailed structural inspection of the container before loading the flexitank and to use sound containers with appropriate certificates.
