The procedures were developed for assessing the significance of defects found by inspection or excavation for BP’s Finnart-Kinneal crude oil and multi-product pipelines in Scotland, its deepwater Mardi Gras system in the Gulf of Mexico, and the BTC pipeline in Azerbaijan and Georgia; however, they are, of course, applicable to any pipeline.
These procedures, known as pipeline defect evaluation procedures (PDEv), have as their objective the provision of procedures that gives guidance on the identification, investigation, and assessment of defects in a pipeline system. The requirements and timescales for remedial actions are also defined.
The procedure gives details of the following:
identification of defect types (using photographs and diagrams);
inspection requirements (what should be measured) for different defects;
assessment and categorization of defects according to their type and location;
actions to ensure safety following defect identification (e.g. pressure reduction);
actions to be taken, with timescales, following defect categorization;
the reporting procedure for the defect assessment;
the requirement for further inspection or expert referral of defects;
options for defect repair (such as cut-out, sleeve, composite, grind).
The majority of pipeline defects are covered by the procedures, including those resulting from internal and external corrosion, dents and ovalities, gouges, dent-gouge combinations, cracking, and manufacturing and construction defects.