Undermatching and Low Strain In-Service Failures in X70 Line Pipe: Contributions From Standards, Specifications and Coating

Author(s):  
Frank Barbaro ◽  
Leigh Fletcher

Abstract Some 10 incidents of low strain in-service and pre-service hydrotest failures in girth welds have been reported in North America since the Enterprise Products ethane pipeline failure in 2015. No such failures have been reported in Australia, despite the similarities in Standards, the line pipe data, and the use of manual SMAW using fully cellulosic procedures. There are however significant differences that warrant further investigation and adoption in terms of best practice to ensure the security and safety of our pipeline networks. Some unique differences and observations in terms of pipe properties, weld qualification procedures, test methods and even full scale pressure burst tests before and after coating are described to highlight subtle differences in the standards that may provide clarity in explaining pipeline girth weld failures and it is anticipated may also provide guidance for the future.

Author(s):  
Brian N. Leis

The consequences of a dynamic fracture in a gas-transmission pipeline require that they be designed to avoid such incidents with great certainty. Because of the complexity of this fracture process, the only certain approach to determine fracture-arrest conditions involved full-scale experiments. As time passed empirically calibrated balance equations between the crack-driving conditions and the line-pipe steels crack-arrest capabilities were developed. Such models worked well until the introduction of high-toughness line pipe, for which to full-scale test predictions were non-conservative, and increasingly so as toughness increased. Problems with early CVN-based models led to development of alternative schemes. This paper presents results of experiments done to evaluate plausible alternatives to the CVN practice, which rely on an impact test identical to or adapted from the drop-weight tear-test (DWTT). As this practice is comparable to that of the CVN practice save for using an up-scale specimen geometry, results are presented and contrasted for these test methods, for pipe grades from B to X70, and toughness from less than 10 J in excess of 300 J. Data are analyzed to reveal trends not typically reported for such testing. It is shown that there is no essential difference between data developed from the CVN and DWTT practices, provided the results are compared at similar levels of impact-machine excess-energy capacity. Further, it is shown that non-conservative predictions of full-scale test behavior for higher-toughness steels can be traced to using the early CVN-based models at toughness levels well outside the range of their empirical calibration.


Author(s):  
Guiyi Wu ◽  
Longjie Wang

Development of remote energy requires large pipeline networks to be placed in more challenging environments such as offshore in deeper waters or on land in Arctic or near-Arctic locations. Pipeline installed and operated in such regions may be subjected to large plastic strains. Engineering critical assessments (ECA) are commonly carried out during design, installation and operation of offshore pipelines to determine acceptable flaw sizes in pipeline girth welds. A number of fracture mechanics-based procedures are available for ECA of pipeline girth welds. Most of these methods are primarily stress-based assessments and are therefore not directly applicable to cases where the displacement-/strain-controlled loading generates large amounts of plastic deformation. For such cases, strain-based fracture assessment for pipeline/girth welds should be carried out instead. However, limited guidance on strain-based assessment is available in the current codes and standards used primarily by the oil and gas industries. This paper reviews the existing strain-based fracture assessment methods, and reports the results of preliminary studies performed to compare the methods reviewed with the available full-scale pipe test data.


Author(s):  
Richard Kania ◽  
Ralf Weber ◽  
Stefan Klein

The occurrence of low-frequency Electric Resistance Welded (LF-ERW) or Electric Flash Welded (EFW) line pipe imperfections has been the root cause of many integrity management initiatives to minimize and mitigate the risk of pipeline failure across the oil & gas pipeline industry. Since their first appearance in the 1920s, defects in or near the LF-ERW and EFW seam repeatedly lead to either hydrostatic test or in-service failures. Where in the past In-Line Inspection (ILI) technologies might have experienced limitations in addressing vintage ERW line pipe defects, modern smart ILI technologies show enhanced capabilities. High resolution Electro-Magnetic Acoustic Transducer (EMAT) and Circumferential Magnetic Flux Leakage (CMFL) ILI technologies have advanced in the recent years enabling more challenging inspections. This paper summarizes the inspection results of 22″ ERW line pipe defects detected and reported by EMAT and CMFL. Correlation of ILI and manual NDE data enables evaluation of current ILI capabilities and improvement of current defect assessment methods.


2017 ◽  
Vol 11 (2) ◽  
pp. 143-168
Author(s):  
Aditya Paramita Alhayat

Meskipun Indonesia telah mengenakan tindakan anti-dumping terhadap beberapa jenis produk baja, namun impor produk tersebut masih meningkat. Salah satu kemungkinan penyebabnya adalah importasi melalui produk yang dimodifikasi secara tidak substansial atau melalui negara ketiga yang tidak dikenakan tindakan anti-dumping, yang dalam perdagangan internasional umum disebut sebagai praktik circumvention. Studi ini ditujukan untuk membuktikan bahwa circumvention mengakibatkan tindakan anti-dumping atas impor produk baja Indonesia tidak efektif dan untuk memberikan masukan berdasarkan praktik di negara lain supaya kebijakan anti-dumping Indonesia lebih efektif. Circumvention dianalisis dengan membandingkan pola perdagangan antara sebelum dan setelah pengenaan bea masuk anti-dumping (BMAD) menggunakan data sekunder dari Badan Pusat Statistik (BPS) maupun Global Trade Information Services (GTIS). Hasil analisis menunjukkan adanya indikasi kuat bahwa circumvention mengkibatkan pengenaan tindakan anti-dumping impor produk baja di Indonesia menjadi tidak efektif. Oleh karena itu, sangat penting bagi Pemerintah Indonesia untuk segera melakukan penyempurnaan terhadap Peraturan Pemerintah No. 34/2011 tentang Tindakan Antidumping, Tindakan Imbalan, dan Tindakan Pengamanan Perdagangan dengan memasukkan klausul tindakan anti-circumvention yang setidaknya mencakup bentuk-bentuk dan prosedur tindakan, sebagaimana yang telah dilakukan beberapa negara seperti: AS, EU, Australia, dan India. Although Indonesia has imposed anti-dumping measures on several types of steel products, the import of steel products is still increasing. One possible cause is that imports are made by non-substantial modification of product or through a third country which is not subject to anti-dumping measures, which is generally referred as circumvention practice. This study is aimed to prove that circumvention made Indonesian anti-dumping actions on the steel products ineffective. This also study provides recommendation for a best practice for other countries so that Indonesia's anti-dumping policy can be more effective. Circumvention was analyzed by comparing trade patterns between before and after the imposition of anti-dumping duty using secondary data from the Central Bureau of Statistics (BPS) and the Global Trade Information Services (GTIS). The results of the analysis indicate that circumvention became the reason why Indonesian anti-dumping measures on imported steel products are ineffective. Therefore, it is very important for the Government of Indonesia to immediately make amendments to the Government Regulation No. 34/2011 on Antidumping, Countervailing, and Safeguard Measures by adopting clauses of anti-circumvention. This can be done bycovering the forms/types and procedures of action, as has been implemented by several countries such as the US, EU, Australia, and India.


2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Elizabeth Wager ◽  
◽  
Sabine Kleinert

Abstract Background Inaccurate, false or incomplete research publications may mislead readers including researchers and decision-makers. It is therefore important that such problems are identified and rectified promptly. This usually involves collaboration between the research institutions and academic journals involved, but these interactions can be problematic. Methods These recommendations were developed following discussions at World Conferences on Research Integrity in 2013 and 2017, and at a specially convened 3-day workshop in 2016 involving participants from 7 countries with expertise in publication ethics and research integrity. The recommendations aim to address issues surrounding cooperation and liaison between institutions (e.g. universities) and journals about possible and actual problems with the integrity of reported research arising before and after publication. Results The main recommendations are that research institutions should: develop mechanisms for assessing the integrity of reported research (if concerns are raised) that are distinct from processes to determine whether individual researchers have committed misconduct; release relevant sections of reports of research integrity or misconduct investigations to all journals that have published research that was investigated; take responsibility for research performed under their auspices regardless of whether the researcher still works at that institution or how long ago the work was done; work with funders to ensure essential research data is retained for at least 10 years. Journals should: respond to institutions about research integrity cases in a timely manner; have criteria for determining whether, and what type of, information and evidence relating to the integrity of research reports should be passed on to institutions; pass on research integrity concerns to institutions, regardless of whether they intend to accept the work for publication; retain peer review records for at least 10 years to enable the investigation of peer review manipulation or other inappropriate behaviour by authors or reviewers. Conclusions Various difficulties can prevent effective cooperation between academic journals and research institutions about research integrity concerns and hinder the correction of the research record if problems are discovered. While the issues and their solutions may vary across different settings, we encourage research institutions, journals and funders to consider how they might improve future collaboration and cooperation on research integrity cases.


2019 ◽  
Vol 4 (Supplement_1) ◽  
pp. 12-22 ◽  
Author(s):  
Susan B Sisson ◽  
Kaysha Sleet ◽  
Rachel Rickman ◽  
Charlotte Love ◽  
Alexandria Bledsoe ◽  
...  

ABSTRACT Background Native American (NA) children have a high prevalence of obesity contributing to lifespan health disparities. Dietary intake is important to promote healthy weight gain, growth, and development. In 2017, the USDA enforced changes to the Child and Adult Care Food Program (CACFP). The CACFP provides reimbursement to qualifying Early Care and Education (ECE) programs that serve foods that uphold the program's nutrition requirements. Objective This study had the following 2 objectives: 1) Describe a novel index to evaluate ECE menus based on revised CACFP requirements (accounting for food substitutions) and best practices for 3- to-5-y-old children, and 2) analyze CACFP requirement and best practice compliance and nutrient changes in 9 NA ECE programs before and after enforcement of the revised CACFP requirements. Methods This longitudinal study is within a larger community-based participatory research study. Menus and meals served were evaluated for 1 wk at each of 9 programs before and after enforcement of the revised meal patterns. Nutrient analysis, CACFP requirement and best practice compliance, and substitution quality were evaluated. Differences were determined using a paired t-test or Wilcoxon matched test. This trial was registered at clinicaltrials.gov as NCT03251950. Results Total grams of fiber consumed increased (5.0 ± 1.2 compared with 5.9 ± 0.8 g, P = 0.04) and total grams of sugar consumed decreased (53.8 ± 12.6 compared with 48.4 ± 7.9 g, P = 0.024), although room for further improvement exists. Although total grams of fat remained unchanged, grams of saturated fat significantly increased (7.8 ± 1.4 compared with 10.5 ± 3.4, P = 0.041). Other nutrients remained unchanged. Overall CACFP requirement and best practice compliance scores improved, although this finding was not statistically significant. No significant changes in food quality associated with substitutions occurred. Conclusions This study provides early evidence to support the beneficial impact of the revised CACFP requirements. Understanding barriers to compliance within rural NA communities would be an important next step in enhancing the health of vulnerable children.


Author(s):  
Hidenori Shitamoto ◽  
Nobuyuki Hisamune

There are several methods currently being used to install offshore oil and gas pipelines. The reel-lay process is fast and one of the most effective offshore pipeline installation methods for seamless, ERW, and UOE line pipes with outside diameters of 18 inches or less. In the case of the reel-laying method, line pipes are subjected to plastic deformation multiplication during reel-laying. It is thus important to understand the change of the mechanical properties of line pipes before and after reel-laying. Therefore, full-scale reeling (FSR) simulations and small-scale reeling (SSR) simulations are applied as evaluation tests for reel-laying. In this study, FSR simulations were performed to investigate the effect of cyclic deformation on the mechanical properties of weldable 13Cr seamless line pipes. Furthermore, SSR simulations were performed to compare the results obtained by FSR simulations.


Author(s):  
Craig Taylor ◽  
Sreekanta Das ◽  
Laurie Collins ◽  
Muhammad Rashid

Very few studies have been conducted concerning fatigue in steel line pipe and fewer using full-scale testing. Further, at the time of this study, no research on full-scale testing was available in open literature regarding fatigue behavior of line pipe with longitudinal cracks, despite being considered more critical than the line pipe with cracks oriented in the circumferential direction. In the current research work, fatigue crack growth was investigated in NPS 20, API 5L X-70 grade, electrical resistance welding (ERW) straight-seam steel line pipes in the base metal and at the weld seam for various orientations. It was found that there was no significant difference between fatigue crack growth in the base metal and at the weld seam for the tested stress ratio. Increasing the angle of inclination of the crack with respect to the weld line was found to decrease the rate of fatigue crack growth due to a decrease in the mode I stress component. Finally, it was observed that despite the difference in fatigue crack growth rates, the crack aspect ratios were nearly identical for all cracks at the same crack depth.


Author(s):  
Hisakazu Tajika ◽  
Takahiro Sakimoto ◽  
Tsunehisa Handa ◽  
Rinsei Ikeda ◽  
Joe Kondo

Recently high grade pipeline project have been planned in hostile environment like landslide in mountain area, liquefaction in reclaimed land or the frost heave in Polar Regions. Geohazards bring large scale ground deformation and effect on the varied pipeline to cause large deformation. Therefore, strain capacity is important for the pipeline and strain based design is also needed to keep gas transportation project in safe. High grade steel pipe for linepipe tends to have higher yield to tensile (Y/T) ratio and it has been investigated that the lower Y/T ratio of the material improves strain capacity in buckling and tensile limit state. In onshore pipeline project, pipe usually transported in 12 or 18m each and jointed in the field. Girth weld (GW) is indispensable so strength matching of girth weld towards pipe body is important. In this study strain capacity of Grade X70 high strain pipes with size of 36″ OD and 23mm WT was investigated with two types of experiments, which are full scale pipe bending tests and curved wide plate tests. The length of the specimen of full scale bending tests were approximately 8m and girth weld was made in the middle of joint length. A fixed internal pressure was applied during the bending test. Actual pipe situation in work was simulated and both circumferential and longitudinal stress occurred in this test. Test pipes were cut and welded, GTAW in first two layer and then finished by GMAW. In one pipe, YS-TS over-matching girth weld (OVM) joint was prepared considering the pipe body grade. For the other pipe, intentionally under-matching girth weld (UDM) joint was prepared. After the girth welding, elliptical EDM notch were installed in the GW HAZ as simulated weld defect. In both pipe bending tests, the buckling occurred in the pipe body at approximately 300mm apart from the GW and after that, deformation concentrated to buckling wrinkle. Test pipe breaking locations were different in the two tests. In OVM, tensile rupture occurred in pipe body on the backside of buckling wrinkle. In UDM, tensile rupture occurred from notch in the HAZ. In CWP test, breaking location was the HAZ notch. There were significant differences in CTOD growth in HAZ notch in these tests.


Author(s):  
Oddvin O¨rjasaeter ◽  
Olav Jan Hauge ◽  
Guy Ba¨rs ◽  
Per Egil Kvaale

Installation of pipelines by reeling has proved to be an effective method. However, the pipe bending results in very high stress and strain and cannot be handled by conventional design rules, as stated in design codes, e.g. [2]: High strain crack growth must be assessed according to specific case-by-case selected criterions. In the present work the performance of 10” and 12 3/4” pipes with typical weld defects is studied — from initiation of cracks at notches to final fracture. Information was obtained from several sources: full scale cyclic bending of pipes, FE simulations, and small-scale tests. The plasticity during reeling operations results in substantial non-linear behavior due to varying cross section properties, cyclic creep, and different material response at tensile and compression side of the pipe. Hence, a full scale reeling simulation must be carefully planned and include sufficient tolerances. Critical cracks in pipe girth welds initiate mainly from the surface (undercuts, lack of penetration, or lack of fusion), but potentially also internally (lack of fusion or large pores). Various configurations of these parameters were investigated in full scale pipe tests. It was possible to verify both crack propagation during the reeling cycles, and the point of final fracture (for ECA verifications). In pipe design on must assure safe conditions for both reeling operations and for later in-service loading. Proper design tools must be available. Several methods for high strain crack growth analysis were considered and also compared to small-scale specimen data. Conventional strain-life methodology failed to predict the crack propagation accurately. A new approach including a tensile strain range parameter offered promising results.


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