Addendum to API RP 1183 for Improved Dent Screening

In December 2020, American Petroleum Institute (API) published Recommended Practice 1183, First Edition (RP 1183), Assessment and Management of Dents in Pipelines. Since being issued, RP 1183 has been applied by pipeline operating companies and engineering consultants providing services to the energy pipeline industry to evaluate dents and deformations on pipeline systems and to support mitigation and repair decisions. RP 1183 includes various screening tools to estimate the remaining fatigue life of a dent in a pipeline.

Based on practical experiences from applying RP 1183 to assessing dents and communications with end users, API became aware that of the various screening tools included in RP 1183, Table 6 (“Dent Fatigue Life Spectrum Severity Criteria”) is not the most conservative dent screening method in all cases (see references listed below). Considering this finding, API issued Addendum 1 to RP 1183 in May 2024, removing Table 6, and its accompanying guidance,  from the document pending completion of revisions to RP 1183 and publication of the second edition, which is currently under development.

API has prepared this alert to raise awareness and inform pipeline operators of the basis for publishing Addendum 1 to RP 1183 and removal of Table 6. Pipeline operating companies should decide whether additional evaluation is needed pertaining to prior analyses of dents and deformations using RP 1183 First Edition.

If any pipeline operator has experienced a dent failure following an engineering assessment using Table 6 of RP 1183, please provide technical information to API’s RP 1183 Task Group through its staff contact, Patty Fusaro, Senior Manager, Midstream Standards, at fusarop@api.org. The RP 1183 Task Group is currently working on the 2nd Ed. of RP 1183. If anyone is interested in participating in this revision effort, contact John Buflod, API, at buflodj@api.org. 

References:

S. Polasik, S. Wu, J. Bratton, R. Dotson and R. Sager, "The State Of Dent Screening And Shape-Based Assessments," 14th International Pipeline Conference, 2022.

X.-K. Zhu, "A verification study of fatigue-based methods in API RP 1183 for estimating fatigue life of pipeline dents," International Journal of Pressure Vessels and Piping, vol. 205, 2023.