Crack detection In-Line Inspection (ILI) is commonly deployed by operators as the primary integrity assessment technique to manage Stress Corrosion Cracking (SCC) due to its coverage and relative convenience. Given the high cost, especially for gas pipelines, crack detection ILI can quickly become non-viable from a budgetary perspective across a large pipeline network. A robust method is required to expedite threat screening across pipelines thus enabling a balanced, cost-effective response.

This paper describes how TAG, a natural gas operator with over 40 pipelines, carrying a credible SCC threat, have developed a comprehensive risk-management process for SCC utilising bespoke software tools to:

• Screen for SCC threat drivers at the network level to prioritise highest threat pipelines
• Visualise joint-level SCC susceptibility per pipeline utilising aligned historical operational, design, environmental and inspection data sets
• Identify priority locations with escalated threat to perform exploratory digs per pipeline
• Enable a continuous improvement loop of ‘training’ the baseline model based on dig results and the collection of complementary datasets until sufficient model performance is demonstrated.
• Act as a central repository to store, align and visualise SCC-related data
• Produce a risk-driven short, medium and long term management plan for each pipeline section.

The process ensures that high-cost integrity management activities such as crack detection ILI are only deployed when the risk is deemed sufficient. Aligned with the industry SCC management best practice of utilising complementary assessment techniques, if ILI is justifiable for any pipeline, the ‘trained’ models also support the prioritisation of ‘true’ SCC amongst the reported population of reported ‘crack-like’ anomalies, further reducing unnecessary spend. Finally the approach described in this paper can also be used as a key SCC management tool where crack detection ILI is not possible. This is currently a significant issue for circumferential cracking in gas pipelines where ILI options are limited.