Advanced ultrasonic techniques in pipeline girth welds examination

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Advanced ultrasonic techniques in pipeline girth welds examination

Cataldo, Giuseppina / Legori, Roberto

Installation of pipelines onboard a lay-barge requires rapid inspection and judgement of all girth welds prior to leaving the vessel. Furthermore, the new philosophy of Engineering Critical Assessment (ECA) based on the principles of fracture mechanics to assess the severity of a defect on its vertical extent requires the application of an inspection system able to accurately assess height, length and through thickness location of the defect in order to reducing the number of unnecessary repairs. Automated Ultrasonic Testing (AUT) is rapidly replacing radiography as standard method of inspecting pipeline girth welds, reducing pipeline costs through increased productivity and avoiding the radiation hazard and the chemical waste of the film processing. This paper describes SAIPEM experience with the new Phased Array AUT technology carried out on several projects, particularly with reference to the ultra-deep water Blue Stream Project, which required an extensive qualification of the AUT System in accordance to DNV Rules (1,2).