The occurrence of ground-piercing activity such as excavations in the vicinity of buried onshore pipelines can lead to an inadvertent impact of the pipeline wall, for example by an excavator bucket. This impact can lead to damage such as a dent, a gouge, or a combination of the two.
The implication of the damage depends on the dent depth, the gouge depth, and the gouge length. A dent alone does not generally have any safety implications, although it affects serviceability. However, depending on the depth of the gouge, a breach of the pipeline wall can occur which, depending on the length of the breach, can lead to a rupture running up to several pipe lengths.
Third Party Damage is recognised as one of the major causes of pipeline failure. There are a number of different approaches available for Third Party Damage Assessments. AFAA adopt a probabilistic approach that compares the failure probability for four of the most commonly used approaches.
AFAA have developed very sophisticated in-house software for undertaking Third Party Damage studies, it has been subjected to extensive validation and verification processes.