Integrity Assessment of Pipelines Containing Circumferentially Oriented Surface Defects

Abstract

The main external defects on pipelines can be introduced during handling, welding and during service by the aggressiveness of the soil. Mechanical damage scratches occur during handling, storage, laying, backfill, rip rap dumping, etc. ll these defects present on the external surface of the pipe, significantly reduce its strength and constitute potential sources of damage. The hydrostatic test has little value for circumferential defects; the main stress is in the direction of the hoop and has little significance for defects. Therefore, the hydrostatic test is not a test for defects located on the circumference of the pipe. This approach will address the weaknesses of the hydrostatic test when assessing the structural integrity of pipes with circumferential surface defects using non-destructive examination (NDT) in-depth and a numerical simulation before the commissioning of the defective pipe.