There are several forms of material degradation that can affect the long-term integrity of buried pipelines, such as generalized corrosion, stress corrosion cracking, and fatigue crack growth. Pipeline operators must periodically assess the condition of their pipeline systems and address current repair priorities and then schedule the next inspection and maintenance programs. The analyses described in this paper have been used to determine the growth of typical cracks that could be found on buried pipelines using the pipeline operating pressure history and fracture mechanics techniques. The details that have been examined include the characterization of the pressure history using rainflow counting techniques and a review of typical pipeline defect types. Examples are provided to describe how the following variables affect the predicted crack growth history: • Pressure histogram ‘bin size’; • Initial crack dimensions. The general techniques and procedures can be used as an integral part of a pipeline integrity management program to establish failure risks and to schedule regular maintenance activities.

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