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Stress Corrosion Cracking on Insulated High-Temperature Pipelines, AER Bulletin 2021-36

Link to Bulletin Summarized

Oil and Gas – Pipeline Inspections

The AER observed numerous pipeline incidents over the past five years resulting from stress corrosion cracking. The incidents involved high-temperature carbon steel surface pipelines that had mineral wool insulation and aluminum cladding but no external corrosion barrier under the insulation. The AER noted that the pipelines lacked this barrier because of their high operating temperature. The AER was concerned with these incidents, as they were occurring in areas of relatively low stress, such as straight sections.

The AER emphasized that licensees are required to consider the risk of corrosion cracking as part of their integrity management program.

Following the occurrences, the AER recommended that licensees:

  • Conduct an engineering assessment to determine whether the insulated pipelines are susceptible to stress corrosion cracking and what portions could be susceptible to failure;

  • Inspect pipelines that may be at risk. If there is a potential that the insulation is wet, select representative locations on the pipeline and conduct investigative inspections to identify corrective actions;

  • Evaluate and repair potential defects according to CSA Z662-19 clauses 10.10 and 10.10.5;

  • Consider replacing old cladding and incorporate new cladding designs and techniques into pipeline construction practices to help prevent moisture from accumulating;

  • Review leak detection programs, including right-of-way inspection, and adjust as necessary;

  • Report any leak and rupture incidents to the AER as per standard reporting requirements; and

  • Advise the local AER field center of insulated pipelines with stress corrosion cracking, even if they are not leaking, and adjust inspection and leak detection programs in response to findings.

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