This assessment addresses the reported lamination on NGL service pipeline. The 30/32” pipeline was built in 1974 transporting C3+ NGL with a total length of 13.82 kilometers. According to API 5791 “Laminations are a plane of non-fusion in the interior of a steel plate that results from the steel manufacturing process and exist on one or more planes in the equipment”. The pipeline was built with non-HIC resistant material which support the existence of the lamination in the pipeline.

Recent conducted In-Line-Inspection (ILI) run reported high metal loss under identified lamination. Integrity Fitness for Service (FFS) was conducted according to API 579 Part 13 – Assessment of Lamination to evaluate the risk associated with this defect. The conducted FFS did not meet the standards requirements for conventional repair since the lamination identifications observed continuous and interacting with the girth welds based on the several inspection techniques findings applied in the field.

Accordingly, alternative repair methodology was developed as recommendation to be implemented in order to protect the pipeline and ensure mitigation measures are in place to resolve the risk associated with the lamination defects. In addition, due to the unknown extent of the lamination along the pipeline length, safe operating pressure evaluation was conducted to estimate the safe pressure until the completion of the UTCD ILI run in order to detect the magnitude of the lamination and to repair all alarming findings.