Length adaptive pressure assessment (L.A.P.A.) of metal loss data
Pipeline Integrity International has developed a method for the assessment of pipeline inspection tool data that will likely reduce the conservatism inherent in methods currently employed. This development has been undertaken in response to the industry's requirements for more accurate prioritization of anomalies and allows for precise excavation and repair of those defects that pose a threat to the integrity of the pipeline. Such analysis enables rehabilitation strategies to be developed on sound engineering principles rather than in reaction to codes that are recognized as being ultra-conservative. In recent years, the introduction of RSTRENG has led to a more precise way of assessing metal loss and therefore the actual strength of the remaining pipe wall. The use of RSTRENG has gained wide acceptance in the pipeline industry. However, it is a tool that must be used 'in the ditch' after the excavation has been performed. One can argue that once the costs of excavating the defect have been incurred, the value of RSTRENG as a cost saving tool is significantly diminished. What is needed then is a method for analyzing metal loss data collected by an accurate inspection tool, incorporating the benefits of RSTRENG'S more accurate evaluation of remaining pipe strength prior to incurring the costs of excavation. This document addresses the evolution of defect assessment methods and subsequent evolution of data processing and reporting techniques, a more specific overview of the RSTRENG method, and describes the new approach for assessing metal loss data from an inspection tool: Length Adaptive Pressure Assessment (LAPA). Pipeline operators who use LAPA have experienced lower populations of metal loss called out as 'significant'. Although the LAPA method is relatively new, the information the authors receive from clients indicates that the approach holds a great deal of promise for realistic prioritization of repairs while still maintaining a consistent and prudent safety factor.
- Research Organization:
- Pipeline Integrity International, Houston, TX (US)
- OSTI ID:
- 20002583
- Report Number(s):
- CONF-990401-; TRN: IM200002%%583
- Resource Relation:
- Conference: Corrosion NACExpo 99, 54th Annual Conference and Exposition, San Antonio, TX (US), 04/25/1999--04/30/1999; Other Information: 1 CD-ROM. Operating Systems: Windows 3.1, '95, '98 and NT; Macintosh; and UNIX; PBD: 1999; Related Information: In: Corrosion 99: Proceedings, [3500] pages.
- Country of Publication:
- United States
- Language:
- English
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