Kiefner and Associates Inc.

Worthington, OH, United States

Kiefner and Associates Inc.

Worthington, OH, United States
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Farrag K.A.,Gas Technology Institute | Francini R.B.,Kiefner and Associates Inc.
Proceedings of the Biennial International Pipeline Conference, IPC | Year: 2010

The paper presents the results of a testing program to characterize mechanical damage (dents and gouges) to pipelines at low operating pressures (i.e., at stress levels below 40% of the Specified Minimum Yield Strength, SMYS of the pipe material). The testing program was performed on pipelines of different sizes and grades; and the pipes were subjected to various gouges and dents when pressurized at 40% SMYS. The results of rupture tests on the pipes were compared with the 'European Pipeline Research Group (EPRG) Simplified Model' criterion. The results show that the model is sufficiently conservative to be used for evaluating mechanical damage of low-stress gas pipelines. The results provide guidelines for gas utilities to assess the damage at these stress levels. These guidelines allow a pipeline operator to assess the repair needs of a pipeline based on its operating pressure and damage level. Copyright © 2010 by ASME.


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).


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).


Quickel G.T.,DNV GL | Beavers J.A.,DNV GL | Kiefner J.F.,Kiefner and Associates Inc. | Leis B.N.,Consultant Inc.
Proceedings of the Biennial International Pipeline Conference, IPC | Year: 2014

On November 1, 2007, a liquid propane pipeline ruptured near Carmichael, Mississippi. Several pipeline industry experts collaboratively concluded the likely origin of the failure was a defect in the longitudinal electric resistance welded (ERW) seam.[1] These experts also noted that a seam-integrity assessment did not prevent the failure. Following the National Transportation Safety Board's (NTSB's) public report, they issued Recommendation P-09-1, which called upon the Pipeline and Hazardous Materials Safety Administration (PHMSA) to conduct a comprehensive study to identify actions that can be used by operators to eliminate catastrophic longitudinal seam failures in pipelines, and indicated the required scope. NTSB directed that PHMSA conduct a comprehensive study of ERW pipe properties and the means to assure that they do not fail in service. Battelle contracted Kiefner and Associates, Inc. (KAI) and Det Norse Veritas (U.S.A.), Inc. (DNV) with the objective to assist PHMSA in favorably closing NTSB Recommendation P-09-1. One of the tasks performed by DNV was to identify the best method(s) to characterize the toughness properties of ERW seams.[2] The objectives of the task were met by performing 1) a literature search to identify current and new practices for characterizing seam weld properties and 2) Charpy V-notch (CVN) impact testing. The findings from the literature search support the use of the Charpy test for the assessment of the toughness of line pipe steels in general, and the ERW weld seams in particular. CVN testing was performed on specimens 1) where the notch varied in circumferential location from the bond line and 2) on bond line specimens, at and away from seam weld features/defects. The results indicated a significant decrease in the Charpy energy for non-post weld heat-treated (PWHT) pipe with decreasing distance from the bond line. Surprisingly, the Charpy energies (upper shelf) at the bond line were higher adjacent to the five confirmed (lack of fusion) LOF defects compared to away from the defects. Failure pressure calculations using CorLAS™ on various (direct current) DC ERW failures, where the pipe dimensions, tensile properties, and flaw geometry were known, revealed that very low Charpy energies (<1.4 J, [1 ft lb] back-calculated) are needed to cause failure. While the data are very limited in this study, they do not support the notion that CVN tests of the bond line can be used in integrity assessments of bond line defects. This paper will outline some basic steps to be performed to establish a range of bond line Charpy energies. Copyright © 2014 by ASME.


Smart L.,Kiefner and Associates Inc. | Haines H.,Kiefner and Associates Inc.
Proceedings of the Biennial International Pipeline Conference, IPC | Year: 2014

It is important to validate the accuracy of in-line inspection (ILI) tools to know how many excavations are needed to maintain the integrity of a pipeline segment. Performing sufficient excavations is important to ensure there are no defects left in the pipeline that have even a remote chance of failure. In some cases additional excavations may be necessary to ensure safety where in other cases no excavations may be necessary. This paper looks at using spatially recorded metal-loss data collected "in-the-ditch" to measure the accuracy of ILI tool results. Examples of spatial in-ditch data are laser scans for external corrosion and UT scans for internal corrosion. Spatially mapped metal loss, because all of the corrosion area is mapped, has the advantage of allowing more comparisons to be made for a given corrosion area and also allows the interaction among corrosion pits to be studied for examining burst pressure calculation accuracy. From our studies we find the depth error for shallow corrosion 10%-20% wt deep is often not representative of deeper corrosion in the same pipeline and the interaction criteria for ILI tools needs to be larger than the interaction criteria for in-ditch data. Examples are shown with these types of results, and by interpreting the results in conjunction with API 1163, certain ILI runs are shown that require no excavations where others may require additional excavations than suggested by normal +/-10% wt ILI data. Copyright © 2014 by ASME.


Kiefner J.F.,Kiefner and Associates Inc. | Nestleroth J.B.,Kiefner and Associates Inc. | Beavers J.A.,DNV GL | Maier C.J.,DNV GL
Proceedings of the Biennial International Pipeline Conference, IPC | Year: 2014

The track record of in-line inspection crack detection technology with respect to locating and characterizing seam defects in electric-resistance-welded (ERW) pipe was examined on the basis of 13 tool runs on 741 miles of hazardous liquid and natural gas pipelines. Results for three types of tools were examined: (ultrasonic angle beam, circumferential magnetic flux, and electromagnetic acoustic transducer (EMAT). The methods for validating the locations, types, and sizes of anomalies included in-the-ditch NDE (UT and MT), and removal of pipe for metallurgical investigation and/or burst testing. The work indicates that in-the-ditch NDE is not always reliable for confirming the ILI findings. The metallographic examinations and burst tests sometimes confirmed the ILI findings, but in other cases, they revealed defects did not compare well in size with the anomalies indicated by the ILI or the in-the-ditch NDE. In some cases, anomalies that caused failures in burst tests had not been identified by the ILI. Because the toughness of the bond line region may differ significantly from that of adjacent material, predictions of failure pressure based on ILI-indicated dimensions using a single toughness level are unreliable. It is concluded that significant improvements in ILI crack-detection technologies will be needed in order for pipeline operators to be able to have adequate confidence in the ERW seam integrity of a pipeline inspected by means of an ILI crack-detection tool. It is also concluded that significant improvements of in-the-ditch NDE methods are needed for such methods to be considered a reliable means of validating ERW seam anomalies found by ILI. These results should not discourage the use of technologies for ERW seam integrity assessment. The tools clearly are useful for finding and eliminating some seam defects. Only by continuing to use and develop the tools can pipeline operators expect to see the technologies improve to the point where operators can have a high degree of confidence in the ERW seam integrity of an inspected pipeline. Copyright © 2014 by ASME.


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.


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.


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.


Haines H.,Kiefner and Associates Inc. | Johnston D.,Kiefner and Associates Inc.
NACE - International Corrosion Conference Series | Year: 2010

ILI data typically has an uncertainty associated with the reported anomaly size. Typically this is reported as ±10 percent of the wall thickness for 80% of the data. This uncertainty is also present in the failure pressure calculated from the ILI data. Pressure calculations are often applied using a two parameter assessment method such as modB31G or an effective area calculation such as KAPA or RSTRENG. Effective area calculations are often preferred because there is less conservativeness in the failure calculation. Recently the authors studied the effect of tool uncertainty on the uncertainty of the calculated failure pressure through modeling. While modB31G calculations have a fair amount of uncertainty in the calculated failure pressure, caused by the uncertainty of the tool sizing the flaw, effective area calculations have less uncertainty. This paper shows an example of this reduced uncertainty from theoretical calculations. As a result of this work we believe there are two reasons to use effective area calculations with ILI measurements, one because the calculated failure pressures are less conservative and two because there is less statistical uncertainty in the calculated failure pressures. © 2010 by NACE International.

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