Development of Long Range Ultrasonic Methods of Assessing Pipeline Condition (Phase 4)

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Abstract:

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Need: Previous work to develop a long range low frequency ultrasonic technique for detection of corrosion and other flaws in long lengths of pipeline, both above ground and buried has demonstrated the applicability of the technique on 18in. and 36in. pipe and that metal loss defects can be detected. However, the site trial conducted in the previous phase on a buried line with a bitumastic coating demonstrated that a more easily deployable transducer was required and that there is a significant attenuative effect due to bonded bitumastic coatings.

Result: The purpose of this phase of the work was to establish the performance of the technique with regard to defect detection, so that its application as a field inspection tool could be assessed. To this end, trials were conducted at the GRI West Jefferson Pipeline Simulation Facility near Columbus, Ohio, on a 24in. diameter specimen, situated in the pull rig, containing 128 controlled, well documented metal loss defects, used primarily to assess resolution of internal inspection tools.

Benefit: An extensive study was carried out on this specimen, which enabled firm conclusions to be drawn about the defect detection capabilities of the technique. In addition to this specimen, the flow loop at West Jefferson enabled the performance and achievable test range of the 24in. transducer, which was produced to be assessed. Both the flow loop and the defect specimen were coated with fusion bonded epoxy, which enabled the concerns of the NDT Supervisory Committee about the effect of such coatings on the long range ultrasonic technique to be addressed.

Price: $395.00

L51785e is included in the Ultrasonic Pipeline Reports Compendium
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