A pressure surge is generated in a pipeline system when there is an abrupt change in the rate of flow of liquid in the line.
In tanker operations it is most likely to occur as a result of one of the following during loading:
- Closure of an automatic shut down valve.
- Slamming shut of a shore non-return valve.
- Slamming shut of a butterfly type valve.
- Rapid closure of a power operated valve.
If the pressure surge in the pipeline results in pressure stresses or displacement stresses in excess of the strength of the piping or its components, there may be a rupture leading to an extensive spill of oil.