EPRG Tier 2 Guidelines for the Assessment of Defects in Transmission Pipeline Girth Welds

Denys, Rudi; Andrews, Robert B.; Zarea, Mures; Knauf, Gerhard

doi:10.1115/ipc2010-31640

Cited by 8 publications

(10 citation statements)

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“…The measured CVN impact energies were compared with the EPRG toughness requirements of 30J minimum and 40J average [8]. Table 6 illustrates that the minimum and mean weld metal and HAZ CVN energies satisfied the EPRG requirements by a fair margin.…”

Section: Toughness Propertiesmentioning

confidence: 99%

“…3*t or 50 mm (where t is the wall thickness). This defect length corresponds to the EPRG maximum allowable defect length ensuring remote yielding [8].…”

Section: Figure 5: Instrumentation Of Cwp Specimenmentioning

confidence: 99%

“…Additional tests with artificial defects measuring 4mm by 50mm (notch length related to workmanship criteria) were completed to evaluate the sensitivity to notch dimensions and to validate the recommended EPRG defect limits [8].…”

Section: Introductionmentioning

confidence: 99%

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Strain Capacity of Girth Welded Joints in HSAW Pipes

Minnebruggen

Hertelé

2017

Volume 5B: Pipelines, Risers, and Subsea Systems

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The general aim of a recently finalized European project, i.e. EU RFCS SBD-Spipe, is to generate specific know-how concerning the development and possible use of spirally welded pipes for demanding applications. The demanding applications relate especially to structural integrity issues, both onshore and offshore, requiring good performance under application of large strains resulting in buckling, collapse and/or tensile loading. The outcome of this project can also be used as technical basis for improving standards and guidelines, that address design and safety of spirally welded pipelines.The contribution of Ghent University to this project focusses on the aspects of tearing resistance, defect tolerance and strain capacity of girth welded joints subjected to remote axial tensile load. A numerical and experimental approach is used for the assessment of flaw tolerability and strain development upon tensile loading. Spiral pipes of steel grade API-5L X70 with 36" and 48" diameters have been girth welded using both a manual and semi-automatic welding processes. Curved wide plate specimens have been extracted from the pipes and artificial weld defects have been introduced. The specimens have been loaded in tension up to failure at a temperature of -10°C. This paper reports on the experimental result of a series of curved wide plate tests. INTRODUCTIONSpiral welded pipes are employed in large-diameter pipeline applications for the transportation of hydrocarbons in strainbased design related projects due to economic benefits in comparison with traditionally used UOE pipes [1]. In the field of onshore pipelines, spiral welded pipes have gained large market shares, as an alternative to longitudinal seam welded pipes for oil and gas pipelines. However, there exists a debate on whether such pipes can also be considered for relatively shallow-water off-shore pipeline applications as well as in geohazard areas. As a result, spiral welded pipes have only limitedly been employed

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Section: Toughness Propertiesmentioning

confidence: 99%

“…3*t or 50 mm (where t is the wall thickness). This defect length corresponds to the EPRG maximum allowable defect length ensuring remote yielding [8].…”

Section: Figure 5: Instrumentation Of Cwp Specimenmentioning

confidence: 99%

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Strain Capacity of Girth Welded Joints in HSAW Pipes

Minnebruggen

Hertelé

2017

Volume 5B: Pipelines, Risers, and Subsea Systems

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“…To the former's respect, the allowable flaw sizes described in the European Pipeline Research Group (EPRG) Tier 2 'guidelines for the assessment of defects in transmission pipeline girth welds' [9] are proposed. These guidelines provide sufficient conditions for the achievement of remote yielding prior to girth weld failure.…”

Section: 2mentioning

confidence: 99%

“…The evaluated flaw sizes follow from the EPRG Tier 2 guidelines [9] and consider limitations of non-destructive testing.  Extensive testing of both qualification pipes and qualification girth welds is essential to the soundness of the resulting design choices and the documentation of the project.…”

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confidence: 99%

Combined numerical-experimental framework for strain based design and flaw assessment of girth welds

Hertelé¹,

Denys²,

Minnebruggen³

et al. 2013

SCAD

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An increasing number of transmission pipelines have to be installed and operated in harsh conditions, due to the diminishing reserves of exploited fossil fuel sources. Under certain environment related circumstances, longitudinal plastic strains are imposed. When tensile, these may induce failure in girth welds in conjunction with the inevitable presence of weld defects. A large number of factors related to environment, material, geometry and operating conditions influence the tensile strain capacity and, hence, the acceptability of girth weld flaws. Therefore, a project specific development of guidelines in this strain based context is recommended. This paper provides systematic frameworks on (a) how to design pipelines under strain based conditions, and (b) how to assess girth weld flaws that were detected using non destructive testing. Attention is given to several technical and economical aspects related to the selection and qualification of pipe and weld metals, and to the evaluation of flaw acceptability. Both frameworks comprise a combined experimental-numerical approach, collecting project development reports from literature with research carried out at Soete Laboratory. Concretely, four in-house realizations are adopted: the UGent equation for strain capacity, the curved wide plate tension test, the UGent stress-strain equation and a finite element model of full scale pressurized pipe tension testing. The proposed frameworks aim to facilitate in performing thorough and economically justifiable strain based design and assessment processes.Keywords: girth weld; weld flaw; strain based design; strain based assessment; project approach INTRODUCTIONThe availability of fossil fuel reserves decreases [1]. As a consequence, transport pipelines are installed and operated in increasingly challenging circumstances. Such pipelines may suffer from plastic strains that are being imposed under (partially) displacement controlled loading. Their structural integrity is to be judged in a strain based context, which considers strain as an evaluation quantity rather than stress. In this respect, the tensile strain capacity of the structure (i.e. the tensile strain level corresponding with failure of the structure) should exceed the strain demand (i.e. the strain level resulting from the imposed conditions).The strain based evaluation of pipelines under displacement controlled loading can be considered at two stages. First, devoted choices are to be taken during the design stage, prior to the construction of the pipeline. This aspect is referred to as a 'strain based design'. Second, the girth welds that connect pipe sections potentially contain weld flaws. A fracture mechanics based evaluation of their acceptability requires a method for strain based flaw assessment.To date, there are no standardized procedures for the strain based design of pipelines and their girth welds. Further, strain based assessment procedures for girth weld flaws have been developed during the last decade, but all of them show limitations...

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Constraint analysis of defects in strength mismatched girth welds of (pressurized) pipe and Curved Wide Plate tensile test specimens

Verstraete

Waele

Denys

et al. 2014

Engineering Fracture Mechanics

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Please cite this article as: Verstraete, M.A., De Waele, W., Denys, R.M., Van Minnebruggen, K., Hertelé, S., Constraint analysis of defects in strength mismatched girth welds of (pressurized) pipe and curved wide plate tensile test specimens, Engineering Fracture Mechanics (2014), doi: http://dx.doi.org/10. 1016/j.engfracmech.2014.07.018 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Curved Wide Plate (CWP) specimens are often considered to evaluate the tensile strain capacity of girth weld defected pipelines. However, to date no comparison has been made between the constraint in CWP and (pressurized) pipe specimens. This paper reports on the evaluation of the constraint through three dimensional finite element simulations. At first, it is observed that the internal pressure marginally increases the out-of-plane constraint. Second, the CWP specimens appear to closely represent the constraint in pipe specimens for homogeneous as well as strength mismatched situations. CWP specimens become increasingly conservative to pipe specimens with increasing defect dimensions. Constraint analysis of defects in strength mismatchedKeywords: (to be selected from list made available by Elsevier)Constraint effects J-integral Plasticity

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EPRG Tier 2 Guidelines for the Assessment of Defects in Transmission Pipeline Girth Welds

Cited by 8 publications

References 0 publications

Strain Capacity of Girth Welded Joints in HSAW Pipes

Strain Capacity of Girth Welded Joints in HSAW Pipes

Combined numerical-experimental framework for strain based design and flaw assessment of girth welds

Constraint analysis of defects in strength mismatched girth welds of (pressurized) pipe and Curved Wide Plate tensile test specimens

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