External Stress Corrosion Cracking

White Paper: External Stress Corrosion Cracking

External Stress Corrosion Cracking (SCC) of buried onshore pipelines is a time-independent threat to the structural integrity of high-pressure pipelines.

Although no cases of external SCC have been reported in the UK, numerous instances have been reported in Europe, the US, and Canada. Several pipelines in the UK and Europe have been in service for more than 50 years, and the majority of them are protected with Coal Tar Enamel (CTE) and asphalt (bitumen) type coatings that have known associations with external SCC mechanisms.

The detection and management of SCC is more critical when the industry is moving towards the re-purposing of pipelines to transport hydrogen or hydrogen-blended natural gas, as hydrogen can potentially influence the toughness and resistance to crack growth.

This white paper outlines why and where stress corrosion cracking can occur and how operators can detect and manage the threat that external SCC poses to pipelines.