bluuebunny/crossref_metadata_2025_split huggingface dataset:
Initial Experimental and Analytical Efforts to Predict Sustained Load Crack Growth During a Hydrotest and Subsequent Fatigue Crack Growth During Pressure Cycling
Authors: Hioe Yunior , Orth Fabian , Wilkowski Gery , Brust Frederick , Bagnoli Ken 
Published: December 2022

Abstract
Significant efforts were undertaken to develop experimental data to assess the effect of sustained load crack growth during a simulated hydrotest and the effect on fatigue crack growth during subsequent pressure cycling service operation. The pipe used was a 1960ERW 16-inch diameter by 0.250-inch thick X46 pipe. There were a variety of laboratory specimen tests including: standard and isochronous tensile tests at various rates, Charpy transition curves, C(T) J-R curve tests, and SENT J-R curve tests. There were axially surface-cracked pipe tests with monotonically increasing pressure to failure, as well as step-hold pressure tests. Cracks were put in the base metal as well as the ERW seam weld. Some key results to be shown are:
1. The fracture toughness of the base metal and ERW HAZ varies with a/t of the flaw in the SENT testing. Larger a/t specimens have lower toughness. It is believed that this behavior is a key aspect in leak-before-break behavior under pressure loading.
2. Slow strain rate tensile test showed that the yield point decreases with slower loading rates, but the strain-hardening exponent remained relatively constant. The drop in the stress-strain curve causes an increase in the crack-driving force, which is why crack growth can occur with sustained loading.
3. Step-hold pressurized pipe tests with axial surface cracks were conducted with a great amount of data and refined crack growth measurements. In one pipe test, there were four identical flaws. One flaw failed by leakage during a long hold-time. It could be patched, and the other three “identical” flaws all had some small (but different) amounts of ductile tearing. On subsequent pressure cycling, the crack growth rate was incredibly lower than standard fatigue crack growth rates. This was due to the crack retardation effect from the small ductile tear and crack-tip plasticity, with the reverse crack-tip compressive plasticity from unloading after the simulated hydrotest.
The fatigue crack growth rates were about 2 to 3 orders of magnitude slower. The crack retardation benefit easily overcame the small loss in the ligament from ductile tearing. Instead of failure being about 11,300 cycles it took 267,400 cycles. This is a huge benefit for liquid lines. A subsequent follow-on program to this is being undertaken by DOT/PHMSA to better characterize the crack retardation effect and also develop a methodology to predict the “Rupture Free Operational Time” after hydrotest.
Develop Standard Testing Approach for Evaluation of Materials Compatibility in Hydrogen Service
Authors: Chandra Ashwini , Prewitt TJ , Finneran Shane 
Published: December 2022

Abstract
Transformation and decarbonization of existing energy systems are a key part of global energy transition efforts to meet targets set in the COP21 Paris Agreement. In effort to reduce greenhouse gas emissions and decarbonize the existing energy systems, hydrogen has emerged as an attractive fuel option for energy storage and transportation. One key aspect considered is the potential for blending and transporting hydrogen in existing natural gas pipelines. It is recognized that the introduction of hydrogen in existing carbon steel pipelines may present a myriad of effects including hydrogen embrittlement, increases to fatigue crack growth rate, and reductions in ductility and yield strength when exposed to susceptible steels under stress. These potential effects may vary based on the vintage, strength of steel, weld type, and other specific pipeline characteristics, therefore the specific threats and severity of each should be evaluated for numerous pipeline configurations.
Establishing a standard and consistent approach for evaluation compatibility of pipeline materials with hydrogen service would be beneficial to the industry. The existing practice of assessing defects in hydrogen service is based on guidance from ASME B31.12. However, the guidance provided in ASME B31.12 is based on the response of hydrogen at higher concentrations and pressures than will be expected in typical transmission or distribution pipeline systems.
This paper provides a recommended approach to performing testing and analysis for existing and new pipe steels under various hydrogen blends. This would provide a framework across the industry for which a consistent approach for assessing compatibility could be assessed, and allow for improved alignment and compilation of material test data to establish a broader understanding of material compatibility.
Fitness for Service Engineering Assessment of Exposed Pipeline Sections
Authors: Kohandehghan Alireza , Debnath Suborno , Roy Kshama , Wickie Robert 
Published: December 2022

Abstract
Onshore pipelines are usually designed and constructed for burial conditions. However, pipeline exposures can develop from environmental and geohazard conditions such as creek crossing, soil washout due to significant rainfall events, short-term flooding, etc. Engineering assessment of the exposed pipeline sections is a vital consideration to assess the fitness of the exposed pipeline sections for continued service. A fitness for service engineering assessment methodology that was successfully used for the assessment of an NPS 10 onshore natural gas pipeline exposure is presented herein. The assessment is based on finite element analysis to evaluate several damage mechanisms, e.g., lateral and vertical longitudinal bending stresses and strains, buoyancy, hydrodynamic forces, vortex-induced vibration, mechanical damages due to foreign objects impact, and brittle fracture assessment as per failure assessment diagram approach. The proposed framework for the fitness for service engineering assessment of exposed pipe sections presented in this study helps identify potential integrity concerns and prioritize required corrective actions. The proposed methodology offers a robust framework that can significantly improve the operation and maintenance of the existing buried pipelines.
Framework for Pipeline Stress Corrosion Cracking Susceptibility Using Inspection & Mitigation Results: A Bayesian Approach
Authors: Shabarchin Oleg , Koduru Smitha , Hassanien Sherif 
Published: December 2022

Abstract
Stress Corrosion Cracking (SCC) is a form of cracking caused by interaction of a susceptible material, tensile stress, and a suitable environment. Considering recent SCC failures in pipelines coupled with increasingly stringent regulatory requirements, it is imperative for an operator to have an effective SCC integrity management program. To accomplish this, it is essential for the program to not only integrate multiple interacting factors that influence SCC, but also incorporate evidence from program mitigation actions. This paper presents a framework based on Bayesian approach to incorporate multiple lines of evidence while transparently treating associated uncertainty to estimate a more representative SCC occurrence and corresponding SCC failure rate. Knowledge gathered from industry SCC management best practices and SCC susceptibility models are used in conjunction with expert knowledge and ILI findings to develop the proposed framework. The framework consists of two components; first, SCC susceptibility is established to quantify the SCC occurrence rate on a pipeline. Second, field evidence is incorporated into the framework using Bayesian updating to refine the initial estimates of segment specific SCC occurrence and failure rate. The approach provides a significant flexibility to update the proposed model at any maturity level of the program as additional data becomes available.
Different Ways to Reduce Greenhouse Gas Emission in Pipelines
Authors: Zhang Jun , Anderton John , Kane Adrian 
Published: December 2022

Abstract
Pipelines are essential for keeping the lights on, homes warm, plants running, planes flying and water flowing. They also provide one of the safest means of transport. By taking some effective actions, they can contribute to the reduction of greenhouse gas emission significantly.
This paper explores a few ways for pipeline companies to help combat climate change.
There are of course hardware solutions, carbon capture at station equipment such as compressors or heat exchangers. Although undoubtably these solutions work, they are slow and expensive to implement. What we are going to look at are solutions that can be implemented by using existing software tools, or making a relatively small investment in a new software.
The first and most obvious way is the implementation of an effective leak detection program as defined in API 1175. The second way to reduce emission is through the optimization of fuel gas consumption by compressors. The third way is through the improvement of network operations.
With the move to hydrogen and renewable natural gas, pipeline simulation software can also help the pipeline industry to transit to greener energy, thus less emission.
New Findings in Leak Detection on Multi-Phase Pipelines
Authors: Hoffman Andrew , Zhang Jun , Wilkie Jason 
Published: December 2022

Abstract
With the increasing pressure to reduce greenhouse gas emission and protect the environment, effective leak detection in all pipelines has become more critical in recent years. This applies to multi-phase pipelines too. Little progress has been made in multi-phase pipeline leak detection in the last decades. Some of the main challenges in detecting leaks in multi-phase pipelines include:
• Complex and variable hydraulic conditions with flow regime changes when the fluid composition and flow-rate vary in a pipeline
• High cost and poor performance of flow meter instrumentation
• Feasibility of retrofitting leak detection hardware or equipment on operational pipelines.
Over the past few years significant research and field tests have been carried out to develop possible solutions to address the above challenges.
This paper describes some of the technologies tested on a few multi-phase pipelines. It addresses both the hardware and software used to detect leaks, the fluid withdrawal tests carried out and performance achieved. Potential applications and further development are outlined at the end.
New Approaches in Utilizing Eddy Current Testing to Address Pipeline Inline Inspection Requirement
Authors: Cornu Sylvain , Karé Raymond , Sweedy Ahmed , Sirois Michael 
Published: December 2022

Abstract
Eddy current testing is one of the most widely used NDT inspection techniques for both ferrous and non-ferrous materials. This may explain why it was one of the very early techniques implemented on an inline inspection tool (ILI) back in the 1970s, following the first implementation of Magnetic Flux Leakage (MFL) tools. Eddy current testing is primarily developed to accurately detect and size surface breaking defects. The technology is now mature and has been deployed in various applications, most notably for pipeline in-ditch inspection. As of today, the technology as a crack detection technique is not deployed commercially on ILI tools as it can only detect cracks on the inner pipe wall.
The most common use of the eddy current technology in ILI tools is the simple configuration for lift-off measurement. This offers a way to discriminate between internal and external corrosion on a volumetric tool (MFL) or enhance caliper-based geometry measurements. The most advanced applications of eddy current testing are targeting measurement of electromagnetic properties of the pipe wall to either measure material properties (pipe grade) or pipe stress due to external loading. Both pipe grade or pipe stress eddy current technologies can only operate successfully in combination with a magnetically saturated pipe wall, either prior to or during the measurement. The first objective of this development is to remove the requirement for magnetic saturation, thus removing the need for MFL magnets or large electromagnets.
The second objective is to progress the established Eddy current development to allow for the measurement of an additional parameter. Current commercial stress measurement method is uniaxial and aligned in the axial/longitudinal direction with limited coverage around the pipe circumference. The new development will make measurements in 2-D, longitudinal and hoop directions, and will include a full array of sensors to provide a full coverage 2-D stress map of the pipe wall.
The latest development will address accurate detection and sizing of defects on the internal wall of the pipeline. Most crack detection tools are focused on the outer wall, e.g. Stress Corrosion Cracking. However, the growing interest in hydrogen transportation and the potential for Hydrogen Induced Cracking (HIC) on the internal surface of pipelines, has focused the industry on developing tools for internal crack detection. Detection and sizing of surface breaking defects are at the core of eddy current technologies.
Guidelines to Develop Fitness-for-Service Assessment of Exposed Pipeline Due to Flood Events: Investigation, Assessment and Mitigation
Authors: Liu Kaiwen , Beltran Alejandro , Gao Serene , Greig Andrew 
Published: December 2022

Abstract
Over the course of the British Columbia (BC)/ Washington State (WA) flood event, the pipeline restart preparation required a significant, sustained effort to complete a detailed assessment of the pipe’s integrity. Trans Mountain Corporation was able to develop a detailed Fitness-For-Service (FFS) assessment for the exposed pipe segments due to the flood and gain approval from the CER (Canada Energy Regulator) for a successful pipeline restart.
On the evening of November 14, 2021, the Trans Mountain Pipeline LP (Trans Mountain) pipeline was shut down as a precautionary measure in response to an ongoing extreme rainfall event. There were multiple sites identified as critical pipe exposures where the pipeline was exposed and unsupported, or experienced mechanical damage, due to soil wash out. All confirmed exposure sites were reported to the CER and Trans Mountain responded in-field to support and protect the pipeline from flowing water, complete pipe inspections, determine the pipe’s FFS, and complete the required repairs before pipeline restart.
This paper provides a summary of the FFS assessment that Trans Mountain completed to ensure the integrity of its oil pipeline system after the significant geotechnical event, and the process followed to develop the long-term integrity plans.
Pipeline Crossing Significant Elevation Difference Terrain Design
Authors: Ma Te , Wu Tiantian , Qiao Sean , Harper Taylor 
Published: December 2022

Abstract
Liquid transmission pipeline systems passing through geological areas with significant elevation changes along their route may possibly run at “slack flow” conditions if improperly designed. Slack flow is a phenomenon in which a pipeline transporting a liquid product develops vapor bubbles at points where the pipeline pressure falls below the vapor pressure of that liquid. Slack flow operating conditions will cause the occurrence of fluid column separation (a portion of the liquid is vaporized), which can result in leak detection system inaccuracy, pipeline vibration (when bubbles collapse) and excessive PIG speed, which makes the pipe difficult to inspect with intelligent PIGs.
To eliminate the occurrence of slack flow as well as to reduce project costs, optimization methods could be used, including smaller diameter pipe, thicker walled (and/or higher-grade) pipe, and the use of a pressure control station (PCS).
The subject pipeline is a proposed liquid transmission pipeline with nominal diameters of 762 mm/914 mm/1067 mm and a length of approximately 1200 km. The pipeline passes through a significant elevation change (1326 m elevation change within 50 km, between mountain top and river valley bottom) where the static pressure can reach as high as 12,200 kPa (at a crude density of 938 kg/m3). Slack flow or overpressure may occur due to this situation if the system is not designed properly.
This paper showcases the pipeline design considerations and methodologies used to solve the slack flow operation condition while avoiding all possible overpressure threats. The considerations include maximum and minimum operating conditions for flow rates and pressures. The system optimization methods include optimizing the installation length of thicker wall pipe (higher design pressure) in combination with designing a pressure control station (PCS). Furthermore, future expansion of the pipeline system was included into design consideration.
With the optimized design, slack flow conditions can be avoided, and the pipeline will be operated in a safe, leak detectable, inspectable (intelligent pigging) and cost-effective manner.
Managing the Threat of Corrosion on the Long Seam
Authors: Davies Christopher , Nasreddine Ranine , Slater Simon 
Published: December 2022

Abstract
The industry has become increasingly aware of the threat posed by selective seam weld corrosion (SSWC). This has been driven by changes made to gas transmission regulation in 2020 and an increased focus on SSWC as a significant threat in both gas and liquid pipelines. A number of historical publications exist, which provide guidance on how corrosion interacting with the long seam can be addressed. However, there has been very little presented in recent years to encompass current understanding of how corrosion on the long seam, and specifically SSWC, can be managed amid present regulation requirements. Operators have recent experience that can be used to develop an optimized approach that includes technology improvements and a much more informed knowledge of how SSWC differs from coincident corrosion.
The aim of this paper is to build on existing guidance and present an optimized approach for managing corrosion interacting with the long seam, with particular attention on differentiating SSWC from coincident corrosion crossing the long seam and defining how both can be assessed to create effective remediation plans. The flow chart considers both types of corrosion and leans on existing guidance and models that can be used to assess anomalies. A key part of the process is to consider susceptibility, material properties and appropriate in-line inspection (ILI) assessments in order to define the most suitable approach based on data and a thorough understanding of the individual pipeline system. Examples will be used to illustrate how the approach can be implemented and on what basis decisions can be made to move through to an optimized remediation plan.
Stress Analysis of ASME Section X Flanges Using Classical Lamination Theory
Authors: Bouzid Sofiane , Bouzid Abdel-Hakim , Ngô Anh Dung 
Published: December 2022

Abstract
Fiber Reinforced Plastic composite flanges are extensively used in pressure vessels and pipping systems working under harsh and corrosive environment. ASME section X gives the design procedure to follow to verify the mechanical integrity and leak tightness of these flanges. Unfortunately, this method treats FRP bolted flange joints using the same analytical approach as that of ASME section VIII div. 1 which is derived for metallic flanges. The approach was developed in the late 30’s for flanges having isotropic material properties while the flexibility of the flange different elements and their elastic interaction is ignored. In the absence of a suitable approach such as one based on classical laminate theory, the structural integrity of FRP bolted flange joints remains an issue and some flange classes and sizes will suffer structural failure.
It is proposed to study ASME section X flanges using a recently developed model based on the classical laminate theory and the flexibility of the different elements to identify those critical ones that needs particular attention with regards to composite material selection and bolting and pressure limits. Parameters such as flange ring rotation and stresses in the bolts, flange and gaskets will be investigated. The study on the strength of FRP flanges described in ASME section X RD-620.1 table, will reveal the most critical size and class flanges and their highly stressed locations. The critical stresses and their locations on the flange will be given for each flange. The study will be conducted on flanges of NPS 1 to 48 and classes from 25 to 150. The analysis will be conducted on flanges fabricated out of Fiberglass Reinforced Plastic (FRP) laminates, manufactured with vinyl ester resins and various types of fibrous glass reinforcing. The study shows that FRP flanges of class 25 and 50 are most vulnerable and should be less loaded.
Managing Rooftopping: An In-Line Inspection Based Approach
Authors: Conrad Brett , Kopp Gerhard , Adamson Ross , Mikalson Tommy , Lai Roger 
Published: December 2022

Abstract
Variation in longitudinal seam weld geometries can pose a challenge for liquid operator’s crack management programs. Both, radial misalignment and angular misalignment (also known as “peaking” or “rooftopping”) contribute to what is termed an “anomalous” seam weld geometry. These anomalous geometries create two challenges for an operator’s crack management program: they can reduce the fatigue life of the seam weld due to an increased stress concentration; and they create an unexpected geometry which challenges crack in-line inspection tools. The combination of these challenges can create a situation where a seam weld flaw can propagate at a higher rate without being detected by in-line inspection technologies, increasing the risk of failure. It is therefore prudent for operators to understand where they may have anomalous seam weld geometries and adjust their crack management plan accordingly.
This paper outlines the approach taken by TC Energy to leverage existing datasets to quantify anomalous seam weld geometries, and more specifically rooftopping, on pipe following an incident. Several different in-line inspection technologies were investigated to quantify the presence of rooftopping, with various levels of success. One of the most promising approaches involved sensor stand-off data of an ultrasonic wall thickness measurement technology. The technology was initially pulled through a calibration spool in which rooftopping was artificially introduced. Through collaboration between the TC Energy and NDT Global, an algorithm was developed to not only detect, but also size the levels of rooftopping within the pipeline. The results of the excavation program found that the technology could adequately detect rooftopping. The absolute sizing of rooftopping is an area of focus for future improvements; however, the ability to detect rooftopping allows for a better understanding of the pipeline system and adds another level of data integration which TC Energy has used to improve their liquids crack management program.