Shipping containers are designed and built to standard sizes. This standardisation makes packing, loading and transporting them around the world a far more efficient process. Similarly, the weight capacity of shipping containers is also standardised.
The shipper is the responsible party for packing and loading cargo into shipping containers. While the shipper has the freedom and flexibility to pack and load cargo accordingly, there are correct loading practices in place.
The weight of the cargo should be evenly spread over the entire area of the container’s floor. If the container weight is densely concentrated, it should be distributed with bedding. A shipper may not exceed the maximum weight capacity of a container. This is better known as the container payload.
Knowing and logging a shipping container’s weight is incredibly important and keeping records of container weights is a necessary precaution all shippers must take. Incorrect weights pose a stability and stress issue for ships. While accidents such as capsizing generally only happen in extreme circumstances, incorrect weights can lead to stacks collapsing and cargo being lost overboard. By far the most important factor to consider is the risk of personal injury or death to seafarers and shore-side workers.
There are three relevant weights concerning shipping containers: The Tare Weight, the Gross Weight and the Payload. These are painted on the outside of the container doors when it is in shipping service or before it has been repainted for another application.