Skip to Main Content
Skip Nav Destination
Asset Integrity Management of Critical Infrastructure
Editor
Mamdouh M. Salama
Mamdouh M. Salama
MMS4Aim LLC, USA
Search for other works by this author on:
Dragan Komljenovic
Dragan Komljenovic
Hydro-Québec, Canada
Search for other works by this author on:
Jovica R. Riznic
Jovica R. Riznic
Canadian Nuclear Safety Commission, Canada
Search for other works by this author on:
ISBN:
9780791887738
No. of Pages:
180
Publisher:
ASME
Publication date:
2024

Pipeline dents form from different causes including third-party damage, backfilling issues, pipe sitting on rocks. US DoT includes dent repair and remediation criteria based upon dent depth, dent location (top or bottom side), pressure cycling, strain, and dent interaction with other threats like welds, corrosion, cracks. These criteria are easy to apply, however, they may cause conservative excavations.

Over 80 deformation excavation results were reviewed in this paper. The results were compared against In-Line Inspection (ILI) reported values.

The paper is targeted to gas pipelines, but some of the conclusions can be applied to liquid pipelines and facilities.

This paper includes a review of in the ditch excavation results versus ILI data. ASME B31.8 includes repair criteria for plain dents considering susceptibility for crack initiation during dent formation. As found results were reviewed and no cracks were found in the majority of excavations with high dent strain.

The depth and strain based dent assessment criteria as required by various government regulations and industry codes have served the pipeline industry as an evaluation method to determine fitness for service. However, this criteria can result in unnecessary excavations. Excavation results are reviewed versus as called to investigate the level of conservatism embedded in critical strain values recommended by ASME B31.8. Megarule Part 2 has a maximum level for dent strain (10%) where engineering critical analysis is not allowed and dent must be repaired. The as found results were compared where this strain level was achieved for any possible crack initiation.

The review results and conclusions will be one source to improve integrity repair decisions and can be used to support modifications of guidelines, standards, or regulatory documents. Information presented will be of interest to pipeline operators, in-line inspection (ILI) companies, integrity management specialists and regulators.

This content is only available via PDF.
You do not currently have access to this chapter.
Close Modal

or Create an Account

Close Modal
Close Modal