This paper provides details on a study performed for a liquids pipeline operator to evaluate the effects of ovality on the mechanical integrity of pipe bends in their 16-inch pipe system. Prior to this study, a caliper tool was run that indicated unacceptable ovality was present in the bends relative to the requirements set forth in ASME B31.4. An engineering investigation was performed based on the methodology of API 579 Fitness for Service. This standard provides guidance on evaluating defects using a multi-level assessment approach (Levels 1, 2, and 3) that rewards rigorous evaluation efforts by reducing the required design margins. Therefore, an extensive evaluation was performed that involved making field measurements of the bends in the ditch. Using these ovality measurements, calculations were performed using the closed-form equations in API 579 for Level 2 assessment. The ovality of several of the bends in the field was deemed unacceptable based on in-field measurements. Consequently, a Level 3 assessment was completed using finite element analysis (FEA). The results of this more rigorous analysis, coupled with more favorable design margins, resulted in this particular bend being acceptable. A tool was developed to permit a general assessment of pipe bends having ovality and was validated by performing a full-scale burst test.
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2012 9th International Pipeline Conference
September 24–28, 2012
Calgary, Alberta, Canada
Conference Sponsors:
- International Petroleum Technology Institute
- Pipeline Division
ISBN:
978-0-7918-4513-4
PROCEEDINGS PAPER
Evaluating the Effects of Ovality on the Integrity of Pipe Bends Available to Purchase
Chris Alexander
Chris Alexander
Stress Engineering Services, Inc., Houston, TX
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Chris Alexander
Stress Engineering Services, Inc., Houston, TX
Paper No:
IPC2012-90582, pp. 791-803; 13 pages
Published Online:
July 25, 2013
Citation
Alexander, C. "Evaluating the Effects of Ovality on the Integrity of Pipe Bends." Proceedings of the 2012 9th International Pipeline Conference. Volume 2: Pipeline Integrity Management. Calgary, Alberta, Canada. September 24–28, 2012. pp. 791-803. ASME. https://doi.org/10.1115/IPC2012-90582
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