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Worthington, OH, United States

Rosenfeld M.J.,Kiefner and Associates Inc.
Proceedings of the Biennial International Pipeline Conference, IPC | Year: 2010

It is often recommended that the operating pressure of a pipeline be reduced prior to investigating suspected mechanical damage in the field, due to the unknown severity of the damage. The primary question is: knowing only what can be inferred from in-line inspection and the characteristics of the pipeline, what is the appropriate amount of pressure reduction? Secondarily, operators also question whether the same pressure reduction is necessary for all pipelines, e.g. different Location Classes, and all modes of damage, e.g. rock-induced damage as opposed to encroachment damage. Two levels of assessment are provided: a conservative "Level 1" assessment relying on mainly qualitative information and requiring no calculation, and a "Level 2" assessment that is considerably more involved but which could justify a smaller pressure reduction in response to the damage. The choice of assessment level will depend on the information available to the operator, as well as on the degree of conservatism the operator desires to invoke. Copyright © 2010 by ASME.

Smart L.,Applus+ RTD | McNealy R.,Applus+ RTD | Haines H.,Kiefner and Associates Inc.
Proceedings of the Biennial International Pipeline Conference, IPC | Year: 2012

In-Line Inspection (ILI) is used to prioritize metal loss conditions based on predicted failure pressure in accordance with methods prescribed in industry standards such as ASME B31G-2009. Corrosion may occur in multiple areas of metal loss that interact and may result in a lower failure pressure than if flaws were analyzed separately. The B31G standard recommends a flaw interaction criterion for ILI metal loss predictions within a longitudinal and circumferential spacing of 3 times wall thickness, but cautions that methods employed for clustering of ILI anomalies should be validated with results from direct measurements in the ditch. Recent advances in nondestructive examination (NDE) and data correlation software have enabled reliable comparisons of ILI burst pressure predictions with the results from in-ditch examination. Data correlation using pattern matching algorithms allows the consideration of detection and reporting thresholds for both ILI and field measurements, and determination of error in the calculated failure pressure prediction attributable to the flaw interaction criterion. This paper presents a case study of magnetic flux leakage ILI failure pressure predictions compared with field results obtained during excavations. The effect of interaction criterion on calculated failure pressure and the probability of an ILI measurement underestimating failure pressure have been studied. We concluded a reason failure pressure specifications do not exist for ILI measurements is because of the variety of possible interaction criteria and data thresholds that can be employed, and demonstrate herein a method for their validation. Copyright © 2012 by ASME.

McCann R.,Applus+ RTD | McNealy R.,Applus+ RTD | Haines H.,Kiefner and Associates Inc.
Proceedings of the Biennial International Pipeline Conference, IPC | Year: 2012

This paper discusses a method based on Bayes' Theorem to estimate the probability that performance of an InLine-Inspection tool satisfies stated sizing accuracy specifications. This leads to a new method for accepting or rejecting tool performance that is entirely different from methods based on confidence intervals. Copyright © 2012 by ASME.

Rosenfeld M.J.,Kiefner and Associates Inc. | Gailing R.W.,Southern California Gas Company
PPIM 2013 - Proceedings of the 25th Pipeline Pigging and Integrity Management Conference | Year: 2013

A discussion on several issues in gas pipeline standards and regulations, historically and currently, nationally and in the state of California, covers the evolution of pipeline pressure testing requirements; records that were specifically required; relation of those records to establishing the maximum allowable operating pressure of a pipeline; existence of the so-called "grandfathered" pipelines; and the significance of recently articulated criteria for records accuracy. This is an abstract of a paper presented at the Proceedings of the 25th Pipeline Pigging & Integrity Management Conference (Houston, TX 2/13-14/2013).

Rosenfeld M.,Kiefner and Associates Inc. | Fassett R.,Kleinfelder , Inc.
Proceedings of the American Gas Association, Operating Section | Year: 2014

Conventional wisdom holds that pipe operating at hoop stress < 30%SMYS will only fail as a leak. Several low stress rupture were reported in 2008-2013. Review of PHMSA reportable incident database and Kiefner failure investigation noticed an interacting threat trend. A presentation covers the causes of service failures at low or moderate stress levels; common factors in lowest stress service failures; interacting threats; and its enhanced definition; limited number of injuries, no fatalities; and the benefits. This is an abstract of a paper presented at the 2014 AGA Operations Conference Proceedings (Pittsburgh, PA 5/20-23/2014).

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