Stress corrosion cracking (SCC) is a major concern for many gas and oil pipeline operators. Extensive efforts continue to be made to develop strategies for a better management of the problem. Predictive models for stress corrosion crack growth were developed using lab testing data, limited inspection and excavation measurements since mid 70s and early 90s, respectively. In this paper, a systematic study of crack growth rates was conducted on the Imperial Oil Rainbow 24 NPS pipeline based on the two consecutive UltraScan Crack Detection (USCD) tool runs and field measurements. Findings of this study provide, perhaps, for the first time since the phenomenon was discovered, a direct measurement of crack growth rates for shallow cracks (in the category of <12.5%wt). Future integrity of the pipeline was assessed and the integrity management strategies were refined using the determined crack growth rate and fracture mechanics based approach. In addition, the susceptibility of SCC was studied in detail using a decision tree approach for data mining. Some important correlations between SCC susceptibility and environmental and mechanical variables were identified and presented. Findings on SCC susceptibility are discussed in terms of environmental and loading parameters such as soil, drainage, topography, pressure, and CP along the pipeline.

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