bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reliability Performance Benchmarks for Low Vapor Pressure Liquids Pipelines
Authors: Bandstra Daryl , Dessein Thomas , Schwing Aaron , Andrew Jim , Moritz Jason 
Published: January 2021

Abstract
The pipeline industry is increasingly utilizing reliability methods as a basis for decision-making when managing the integrity of pipeline systems. In this paper we present a methodology for developing reliability benchmarks for onshore low vapour pressure (LVP) liquids transmission pipelines to enable an operator to evaluate the performance of their pipelines relative to their industry peers. The goals of this methodology are to use an approach that is calibrated to historical performance, that remains interpretable, that can readily be adjusted over time, and that reflects the increased sensitivity of High Consequence Areas (HCAs).
On this basis, the Top Quartile (Q1) and Average historical environmental performance of the top 20 largest liquid pipelines operators were identified as two primary benchmarks of interest. Top Quartile (Q1) environmental performance represents an industry leading benchmark performance while the Average historical environmental performance is representative of typical pipelines. This group of operators was selected on the basis that these major companies operate pipeline networks with comparable complexity, similar integrity challenges and a diverse range of operating environments (urban, rural, etc.). In addition, the length of their respective systems decreases the impact of small sample size issues. The dataset used for calculating the historical environmental performance of these operators was the 2010–2018 PHMSA Hazardous Liquids Incidents and Annual Mileage datasets.
The framework presented in this paper, allows specific reliability benchmarks to be calculated for a given pipeline dependent on the environmental consequences associated with failure of the line. Consequences are considered in order to be risk-consistent between pipelines with different outflow potentials and different land use surroundings (HCA vs. Non-HCA). The heightened sensitivity of HCA areas is considered by including an impact ratio in calculating the reliability benchmarks.
These benchmarks can be used to identify pipelines for additional scrutiny when the expected environmental performance does not meet benchmark levels and to flag areas for further evaluation. Quantifying the failure potential of pipeline segments gives operators insights into which maintenance actions will make the most effective use of the available resources to improve reliability. These benchmarks are calculated directly from historical data using a simple methodology and are easily recalibrated in the future as the performance of the pipeline industry continuously improves to meet increasing societal expectations.
Reliability-Based Assessment of Safe Excavation Pressure for Dented Pipelines
Authors: Okoloekwe Chike , Fowler Matthew , Virk Amandeep , Yoosef-Ghodsi Nader , Kainat Muntaseer 
Published: January 2021

Abstract
Dents in a pipe result in alteration of its structural response when subjected to internal pressure. Excavation activities further lead to change in load and boundary conditions of the pipe segment which may exacerbate the stress state within the dented region. Depending on the severity of a dent, excavation under full operating pressure may lead to failure, injuries or fatalities. Although uncommon, an incident has been reported on a gas pipeline where a mechanical damage failed during investigation leading to one death and one injury [10]. While current pipeline regulations require that operators must depressurize a line to ensure safe working conditions during repair activities, there are no detailed provisions available in the codes or standards on how an operator should determine such a safe excavation pressure (SEP). As a result, the safe excavation process of dents has received attention in the industry in recent years.
A detailed review of the recent research on dent SEP showed that the current recommendations are primarily dependent on one of two aspects: careful assessment of inline inspection (ILI) data, or a fitness for service (FFS) assessment of the dent feature leveraging numerical models. Enbridge Liquid Pipelines had previously demonstrated a feature specific assessment approach which incorporated both ILI data and finite element analysis (FEA) to determine the SEP. This assessment also accounted for uncertainties associated with material properties and ILI tool measurement. In the previous publication, the authors demonstrated a methodology for assessing the SEP of dents at a conceptual level from both deterministic and reliability-based standpoints. In this paper, a validation study has been performed to compare the results of fracture mechanics based FEA models against ten full scale burst tests available in literature. The study showed good agreement of the burst pressure of dent-crack defects predicted by FEA models with those observed in the full-scale tests. The assessment method is further streamlined by incorporating the API 579 [14] Failure Assessment Diagram (FAD) method on an uncracked FEA model as opposed to explicitly incorporating the crack geometry in the FEA model. The results of FEA in conjunction with FAD are compared with the full-scale tests to ensure accuracy and conservatism of burst pressure prediction. A reliability-based approach is then designed which accounts for the uncertainties associated with the analysis. A case study is presented where the reliability-based SEP assessment method has been implemented and feature specific SEP has been recommended to ensure target reliability during excavation.
Effects of Flow Response on the Failure Pressure of Pipelines
Authors: Leis Brian N. 
Published: January 2021

Abstract
The flow properties of line-pipe steels control the failure resistance of the pipe, and as such are key in successful pipeline design, and in understanding the factors controlling failures when they occur. As first-principals predictive models are challenged to quantify the flow response in typical line-pipe steels, engineers must rely on empirically developed properties to support numerical analysis for purposes of design and/or integrity management. Stress-based design logically relies on a limiting stress, whereas strain-based design used to address issues like ground movement relies on a limit strain. Post-yield these limits are coupled through the steel’s stress-strain curve and strain-hardening response. Because the burst-pressure of pipes has been shown to depend on the steel’s collapse stress as well as its strain-hardening exponent, n, engineers will need more that the yield stress, Y, or the tensile stress, T, to adequately characterize a pipeline’s resistance to failure.
This paper presents results for the mechanical properties of line-pipe steels developed up to the ultimate tensile stress, or beyond. These stress-strain curves reflect 1) Grades ranging from vintage A25 through recent X100 production. These results have been analyzed to quantify n, Y, and T. These results have further been trended to relate commonly available metrics like Y/T and n, and provide a rational basis for the choice of properties input to numerical analysis.
It is apparent from this work that current correlations between n and Y/T diverge from the trend for the lower-strength Grades. Further, these results show that within a Grade the value of n is a strong function of the ratio of the actual yield stress (AYS) normalized by SMYS, with this dependence indicative of differences in the chemistry and processing used to achieve the Grade. The effects of n and its dependence on the ratio AYS/SMYS are illustrated regarding the predicted response of line pipes subject to increasing pressure. These predictions have been validated by comparison with results for about 20 full-scale tests to illustrate the viability of this technology.
Improving Reliability of Carbon Steel Girth Welds in Sour Environment
Authors: Sidhar Harpreet , Verma Neerav , Kuo Chih-Hsiang , Belota Michael , Wasson Andrew J. 
Published: January 2021

Abstract
The oil and gas industry has seen unexpected failures of sour service carbon steel pipelines in the recent past. Below par performance of girth welds and line pipe material have been identified as the root causes of such failures. Although mechanized welding can achieve good consistency, the weld region is more heterogeneous as compared to base material, which can lead to inconsistencies and poor weld performance. Overall, the effects of welding parameters on performance of carbon steel pipeline girth welds for sour service are not well understood. Furthermore, industry is moving towards more challenging environments, such as production of hydrocarbons from ultra-deepwater, which further necessitates the need to improve welding practices for additional high criticality applications. Many of the critical parameters for sour service performance will also improve general weld performance for ultra-deepwater. So, there is a clear need to understand the effects of various welding parameters on weld properties and performance.
This effort aims at assessing the effects of key welding parameters on performance of girth welds to develop improved welding practice guidelines for sour service pipeline applications. In this study, several API X65 grade line pipe girth welds were made using commercially available welding consumables. The effects on weld root performance of preheat, wire consumable chemistry, hot pass tempering, single vs. dual torch, copper backing, root pass heat input, metal transfer mode, pipe fit-up (root gap, misalignment) were studied. Generally, carbon steel welds with hardness 250HV or below are considered acceptable for sour service. So, detailed microhardness mapping and microstructural characterization were conducted to evaluate the performance and reliability of welds. It was evident that the welding parameters studied have a significant impact on root performance. Preheat and pipe fit-up showed the most significant impact on weld root performance. Based on the results and understanding developed with this study, recommendations for industry are provided through this paper to improve reliability of pipeline girth welds in sour service application.
Quantifying Risk to Optimize Facility Integrity Management
Authors: Nemeth Alex , Li Lily , Nielsen Andrew , Vignal Geoff 
Published: January 2021

Abstract
Effective asset integrity management is supported through the understanding of the condition of the asset, and the quantification of the safety and uncertainty of its properties. Risk based and risk informed decision making can help operators prioritize inspections and repairs on mainline pipe, as well as within operator facilities. Setting operator system specific targets for reliability and risk can help operators better understand the condition of their system, and provide one means of determining whether integrity action or other risk treatment is required on a specific asset, either on the mainline pipe system or on a facility asset system.
While mainline pipe condition is better understood through the use of inline inspection technology and non-destructive examination in the field, facility piping and storage condition is more difficult to understand due to the complexity and number of segments of assets within an operator’s facility, as well as the unpiggable nature of the majority of facility piping.
To help resolve this issue, a risk quantification can be done for each segmented asset within a facility. A relative ranking of asset risks can help prioritize facility integrity activities and drive the planning and execution optimization. However, simply looking at a relative ranking of asset risks may not be enough to maximize risk reduction and achieve safety and reliability targets.
This paper looks to expand on the implementation of Risk Based Inspection (RBI) standard in API 581 and explore more broadly how facility asset risk results can be used in integrity planning and decision making. The paper also examines the application of using finance principals to better quantify risk and carry out a meaningful cost benefit analysis to optimize integrity programs.
Interpreting a quantified risk dollar amount is an industry challenge, and shedding light onto the value of applying reliability and risk models beyond the safety of an operator’s system can be extremely beneficial for operators to enhance cost efficiency. The quantification of risk helps support the optimization of spend and resource allocation to bring efficiencies into integrity management systems while maintaining focus on the right risk mitigation across an operator’s system.
Achieving Consistent Safety by Using Appropriate Safety Factors in Corrosion Management Program
Authors: Al-Amin Mohammad , Zhang Shenwei , Kariyawasam Shahani , Yan Jason Z. , Matchim Tammie 
Published: January 2021

Abstract
Pipeline operators assess metal-loss corrosion anomalies identified on pipelines to determine whether such anomalies require remediation. The assessment of metal-loss anomalies can be performed using deterministic or probabilistic approach. In deterministic method, the failure pressure ratio (FPR) for a metal-loss corrosion anomaly is evaluated against a predetermined safety factor, where FPR is defined as the predicted burst pressure of the anomaly divided by the maximum allowable operating pressure (MAOP) or maximum operating pressure (MOP). Conservative characteristic values are used for the variables such as measurements of metal-loss, pipe geometry, material properties, operating pressure and assessment model in calculating FPR. Safety factors in deterministic assessment are used to account for residual uncertainties, human error and consequence levels. Safety factors are established in various codes and standards in North America. However, those safety factors are not consistent across codes and standards as demonstrated in this paper. This paper describes the fundamentals of how appropriate safety can be assured for pipelines containing metal-loss anomalies by selecting appropriate safety factors. The effect of using different safety factors on the reliability level of the pipeline system is examined in this study. A set of new safety factors to ensure consistent safety level for pipelines containing metal-loss corrosion are proposed in this paper. The impact of the proposed safety factors on the integrity decisions are also demonstrated.
An Engineering Assessment Methodology to Evaluate Arc Burns
Authors: Kohandehghan Alireza , Prescott Jonathan , Guest Stuart , Lepine Sean 
Published: January 2021

Abstract
Arc burns, also known as arc strikes, are caused by momentary interaction of an electric arc, e.g., welding electrode or welding ground clamp, and a pipe or fitting, upon which a minimal or no amount of weld metal is deposited. Arc burns typically correspond with localized alteration of microstructures, shallow pitting, sharp surface contours, re-melting, and/or cracking. The damaged microstructures manifest in the form of a locally harder material due to accelerated cooling rates. Arc burns mainly form during the pipeline construction and are typically located adjacent to manually installed girth welds. The hard microstructures associated with arc burns are susceptible to hydrogen-induced cracking (HIC) in the presence of atomic hydrogen. Pipeline maintenance codes consider arc burns as defects and require their complete removal by grinding.
Due to the relatively small dimension of arc burns, removal by grinding followed by etching contrast test is often the simplest and most reliable permanent repair for such defects. However, in some circumstances grinding to the maximum allowable depth may not completely remove the affected microstructures. Also, removal of arc burns often requires grinding near girth welds and significant grinding depths may require through-thickness inspection of the welds to ensure safety. Type B pressure containing steel sleeves are another permanent repair method that can be used to repair arc burns or partially removed arc burns within grinding metal loss features. Installation of permanent repairs over an arc burn is costly and may introduce additional or higher risks to the integrity of pipeline when scarce industry studies are available that conclusively demonstrate the dangers of leaving arc burns or partially removed arc burns in pipes.
Despite the need, there is no validated engineering assessment method for the evaluation of arc burns. This paper will summarize an engineering assessment methodology and the findings of the evaluation of crack-free arc burns and partially removed arc burn features for two scenarios on vintage liquid pipelines. A combination of one- and three-dimensional finite element models was utilized to investigate the effect of arc burns and/or partially removed arc burns on the integrity of the pipeline based on plastic collapse, local yielding, and fatigue failure modes. The effect of the buried pipeline profile and soil was considered in the assessment of the axial load capacity of the pipeline. The geometrical and metallurgical stress concentrations of the features were considered in the engineering assessment. The engineering assessment determined if the pipeline with the arc burns and/or partially removed arc burns can survive rupture, brittle fracture, and fatigue damage mechanisms during its operation and if reinforcement of the area or cut-out is required.
Establishing a Detection Threshold for Acoustic-Based External Leak Detection Systems
Authors: Bussière Mathew , Stephens Mark , Derakhshesh Marzie , Cheng Yue , Daniels Lorne 
Published: January 2021

Abstract
A better understanding of the sensitivity threshold of external leak detection systems can assist pipeline operators in predicting detection performance for a range of possible leak scenarios, thereby helping them to make more informed decisions regarding procurement and deployment of such systems. The analysis approach described herein was developed to characterize the leak detection sensitivity of select fiber optic cable-based systems that employ Distributed Acoustic Sensing (DAS). The detection sensitivity analysis consisted of two steps. The first step involved identifying a suitable release parameter capable of providing a defensible basis for defining detection sensitivity; the second step involved the application of logistic regression analysis to characterize detection sensitivity as a function of the chosen release parameter. The detection sensitivity analysis described herein provides a means by which to quantitatively determine the leak detection sensitivity threshold for each technology and sensor deployment position evaluated in a set of full-scale tests. The chosen sensitivity threshold measure was the release parameter value associated with release events having a 90% probability of being detected. Thresholds associated with a higher probability level of 95% were also established for comparison purposes. The calculated sensitivity thresholds can be interpreted to mean that release events associated with release parameter values above the sensitivity threshold have a very high likelihood (either 90 or 95%) of being detected.
Evaluation and Acceptability Criteria for Pneumatic Pressure Tests
Authors: Li Guohua , Tupper Michael , Wei Hong-Chan , House Robert , Bidmus Hamid 
Published: January 2021

Abstract
A pneumatic pressure test can be performed when hydrotesting a pipe is infeasible and/or impracticable. Despite its use throughout the industry, little published reference material is available regarding this important and ubiquitous topic with no known industry codes, standards or criteria identified to provide guidance related to stabilization time, test evaluation, and acceptance criteria.
This paper provides an evaluation of minimum stabilization time for various pipe sizes and lengths obtained from transient, parametric simulation results. By evaluating typical test parameters, the paper concludes that gas mass should be used as the principal evaluation criterion, since it is conserved during testing if there is no leak. This paper introduces an acceptance index for which a test can be accepted provided the acceptance index is within defined lower and upper limits obtained from the accuracy of the pressure and temperature measuring devices.
Field test data from three cases studies are successfully presented to verify the feasibility and validity of the proposed acceptance criteria for natural gas mains pneumatically tested with nitrogen at test pressures in the range of 300 psig (2,068 kPag) to 900 psig (6,205 kPag).
Cracks in Dents: How Can I Use an ILI Robot to Detect Them?
Authors: Guajardo Rogelio , Hennig Thomas , Mendez Carlota , Tarramera Beatriz 
Published: January 2021

Abstract
Cracks in dents or linear anomalies interacting with dents are a major pipeline threat. These combined anomalies represent challenges to the Mechanical Engineers that design ILI tools as they need to keep the sensor in an optimal position towards the inner pipe wall. Ultrasonic Crack (UC) tools consist in a sensor plate with a fixed incidence angle that depends on the coupling medium. This plate is then attached to the skids; these are in constant contact with the internal pipe wall. When the tool interacts with a dent, the incidence angle is not optimal; therefore, detection of any interacting feature is compromised.
By not having the optimum angles in the pipe wall, the amplitudes from the reflections caused by cracks will be attenuated. Depending on the magnitude of the attenuation, these might be below analysis thresholds meaning that an algorithm and/or analyst will not consider them as relevant signals. Up to this point, detection of interacting features sounds like a “guess “ or “luck”. So, how can we use UC inspection to detect the interacting features? How can operators manage their assets knowing that they have dents but there is an uncertainty if there are interacting features?
To answer these questions, a systematic approach had to be used. It consisted of multiple phases where 1.- The mechanical design of the tool was understood, 2.- Simulation campaigns to understand the ultrasonic pulse while interacting with the dent, 3.- Pump tests with artificial features, and 4.- Pump test with real features.
All of the data gathered through the different phases allowed the authors to understand the attributes from the features and conditions that influence detection and identification of cracks in dents. This derived in a performance specification stating the truth capabilities to detect interacting features in a dent. These learnings were applied to commercial inspections where the feedback loop is closed with the field verifications.