bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Significance of Soil Freezing for Stress Corrosion Cracking
Authors: Williams Peter J. , White Thomas L. , Torrance J. Kenneth 
Published: October 2016

The microstructure of soils (the arrangement of pores and voids, aggregation and surface characteristics of particles) is substantially modified by freezing. Soils so modified differ, in a number of important properties, from soils not previously frozen. Furthermore, each time a soil is frozen there is a redistribution of particles, moisture and solutes. Corrosion of buried pipes is known to be related to the ground conditions. Accordingly the particular nature of frozen ground needs consideration in this respect.
Studies of microstructure of samples of freezing, frozen and unfrozen soils, many obtained from a full-scale experimental study of the effects of freezing on a buried pipeline, have provided an explanation for measured changes in bulk geotechnical properties of the materials. The microstructure viewed by optical microscopy, reveals the soil structure as having a complex and striking dependence on freezing history. Scanning electron microscopy shows further details in clay rich soils.
Freezing at temperatures occurring in nature normally does not convert all the soil water to ice. The effects of particle surface forces is to reduce the freezing point of the water nearest a mineral surface. The distribution of solutes is radically altered, with pockets of high concentration interconnected by a liquid phase of varying concentration.
A variety of other effects, relating to chemical and mechanical properties of soils subjected to freezing, have been demonstrated or can be postulated. Some of these are important in corrosion phenomena. The stresses that have been shown to occur in a pipe as a result of frost heave in the freezing soil, will also tend to increase the possibility of stress corrosion cracking.
The CEPA Report on Circumferential Stress Corrosion Cracking
Authors: Sutherby Robert L. 
Published: October 2016

According to the NEB Report of the recent inquiry on pipeline stress corrosion cracking (NEB Order No. MH-2-95), six of the Canadian failures to that time had been leaks resulting from circumferentially-oriented cracks. A review has been made of the five CEPA leaks; two leaks from non-CEPA companies; and a case of non-leaking circumferential SCC, also from CEPA. All of the Canadian cases occurred in regions of west and central Alberta.
Circumferential stress corrosion cracking is a rare cause of pipeline leakage. Canadian cases have occurred in very specific conditions that exist in only a small proportion of the regions where pipelines operate. All cases of circumferential SCC, to date, have occurred under either polyethylene tape or a polyethylene backed shrink sleeve. The SCC appears to have been of the neutral-pH form and initiated and grew in response to high axial stresses generated by soil creep and/or localized pipe bending on slopes of 10° or greater. In this sense, circumferential SCC is a manifestation of a geotechnical instability in an area of SCC susceptibility. It would be prudent for operators of susceptible pipelines to consider the potential risks of such failures and to manage those risks accordingly.
Management of circumferential SCC may be largely achieved by effective management of geotechnical concerns on slopes. Geotechnical programs directed toward preventing soil movement or pipe loading could have benefit with respect to preventing circumferential SCC in susceptible areas. Other management approaches, involving in-line inspection tools, may also be found to have benefit.
Given that circumferential SCC (C-SCC) is driven by geotechnical instability, a significant research effort directed specifically toward C-SCC is not considered warranted at this time. Rather, geotechnical research will augment SCC research in progress to provide insight and capabilities to manage the concern.
To assist pipeline operators, CEPA will issue, in 1998, a revision of the SCC Recommended Practices providing guidance to manage this concern.
The Canadian Energy Pipeline Association Stress Corrosion Cracking Database
Authors: Dupuis Bruce R. 
Published: October 2016

The SCC (stress corrosion cracking) database was initiated by the CEPA (Canadian Energy Pipeline Association) SCC Working. The current generation of the database has a broad scope, containing detailed data for each and every colony and its associated environmental conditions. The database also includes corrosion and dents amongst other integrity concerns to identify any correlation with SCC and provide a common industry data format to investigate these other integrity issues. The intent of the current version of the database is to provide for the most detailed data entry that one could typically capture at an investigative dig. With the wide acceptance of the current version the CEPA database it is evolving into the industry standard for investigative excavation data.
The initial trending results are based on the dataset generated by CEPA member companies, which represents over a thousand investigative excavations. The trend results should only be interpreted broadly at this time, although they do generally support industry’s understanding of SCC.
The development and implementation of the CEPA SCC database is premised on the belief, developed through extensive field investigations and laboratory research, that SCC is not a random development, but it initiates and grows at specific locations susceptible to SCC. It is further premised on the belief that such susceptible sites can be generally located by appropriate prioritization techniques. Thus, the objective of the database is to explore correlation among the various operational and environmental variables to improve the current understanding of how to locate SCC, and in particular ‘significant’ SCC, in order that measures can be taken to prevent operational failures and enhance the safety of Canadian pipelines.
The need for an industry database regarding SCC was identified by the CEPA SCC working group shortly after its formation 1994. It was apparent that the various companies were collecting the field data from investigative excavations in significantly different formats, only some of which were electronic. The need for a common data structure and data repository to facilitate trending was reinforced numerous times at the Banff Conferences and by the NEB during its inquiry into SCC in 1995/96.
Use of the Elastic Wave Tool to Locate Cracks Along the DSAW Seam Welds in a 32-Inch (812.8-mm) OD Products Pipeline
Authors: Maxey Willard A. , Mesloh Raymond E. , Kiefner John F. 
Published: October 2016

The effectiveness of the British Gas elastic wave in-line inspection tool for finding and characterizing cracks along DSAW seams was clearly demonstrated by its use in 42 miles (67.59 km) of Colonial Pipeline Company’s 32-inch (812.8-mm) OD Line 4. Fourteen crack-like anomalies were located and characterized. Subsequent cut outs of the anomalies revealed these to be cracks along and at the toe of the longitudinal seam. All initiated at the OD surface. Some apparently were transit fatigue cracks with no indication of growth in service. Others showed evidence of having been extended by fatigue from service-pressure cycles.
The sizes of the defects were such that they were too small to have failed if the pipeline had been subjected to a hydrostatic test to 100% of SMYS. This was demonstrated not only by calculations for the cutout anomalies, but by the hard evidence of burst test results in which the failures occurred at levels of 126% of SMYS and higher. The results show unequivocally that the elastic wave tool provides a significantly greater validation of pipeline integrity (assuming the located anomalies are removed or repaired) than a hydrostatic test to 100% of SMYS. The results suggest that the reinspection interval for the elastic wave tool could be significantly longer than the hydrostatic retest interval on an equivalent-risk basis.
Relationship Between Apparent (Total) Charpy Vee-Notch Toughness and the Corresponding Dynamic Crack-Propagation Resistance
Authors: Leis Brian N. , Eiber Robert J. , Carlson L. , Gilroy-Scott A. 
Published: October 2016

The consequences of a dynamic fracture in a gas-transmission pipeline require that pipelines be designed to avoid such incidents at a high level of certainty. For this reason, the related phenomonology has been studied since the early 1970s when the possibility of a dynamic ductile fracture was recognized. Full-scale experiments were done to characterize the fracture and gas dynamics associated with this process and empirical models were developed as a means to represent these experiments in a design or analysis setting. Such experiments focused on pure methane gas, and in the early days used steels with toughnesses less than 100 J, consistent with the steel making capabilities of the 1970s. Subsequently, interest shifted to larger diameter, higher pressure, higher BTU “rich” gases requiring higher toughness steels. The full-scale tests conducted to validate the arrest toughness levels determined that these empirical models were non-conservative.
This paper presents a relationship between the dynamic crack propagation resistance and the apparent crack propagation resistance as measured by Charpy vee-notch (CVN) test specimens. This relationship is used in conjunction with the existing Battelle empirical criterion for dynamic-fracture arrest to determine the apparent toughness required to arrest a propagating ductile fracture in gas-transmission pipelines. The validity of this relationship is illustrated by successful predictions of arrest toughness in pipelines under a range of conditions including rich gases and high-toughness steels, including those showing a rising upper-shelf behavior.
Field Full Scale Tests on Longitudinal Pipeline-Soil Interaction
Authors: Cappelletto Andrea , Tagliaferri Roberto , Giurlani Gianmario , Andrei Giuseppe , Furlani Giuseppe , Scarpelli Giuseppe 
Published: October 2016

Recent research on longitudinal pipe-soil interaction shows that traditional analysis models are inadequate and too conservative, especially when cohesive soils are involved. The practical implication for SNAM, whose network extends over the entire Italian territory where slow ground movements inducing longitudinal soil-pipe interaction are frequent, is that the management of the gas pipeline has to rely mainly on field measurements.
The correct assessment of the interaction forces was therefore included as an important part of a wider research program, whose aim is to perform pipe risk analysis by which the structural vulnerability for some SNAM typical scenarios can be quantified as a function of such parameters as the pipe section geometry, the type of soil, the burial depth, the length of pipeline section involved and the magnitude of the soil imposed displacements.
Experimental activities specifically regarding longitudinal, static, interaction problems were carried out; in particular pull-out tests were performed on two out of use pipelines, having two different diameters: 8” and 24”. For each site, four different test conditions were investigated where type and compaction state of the material surrounding the pipe varies. The behaviour of the pipe embedded in the original clayey backfill was compared to that observed after such fill was excavated and replaced around the pipe, to simulate conditions after standard stress relieving works. Different fills where then used, made of either granular soil or granulite; this latter was used in order to ascertain the possible benefits of using light artificial materials to mitigate soil-pipe interaction phenomena. Site testing was accompanied by a careful geotechnical investigation both in the field and in laboratory that included direct shear tests of interfaces using coated steel pipe specimens.
A comparison between the results obtained and the existing state of the art is presented. This comparison allowed to verify the effectiveness of some interpretative models, and in particular the convenience of adopting effective stress based models rather than pure cohesive ones (i.e. total stress), even in the case of clayey soils.
Slackline Testing of the TransAlaska Pipeline System at Thompson Pass
Authors: Baskurt U. J. , Bradshaw Peter M. , Hart James D. 
Published: October 2016

During the summer of 1996, the TransAlaska Pipeline System (TAPS) experienced a vibration problem near Thompson Pass which is 25 miles north of Valdez and is part of the Chugach Mountain Range, the most southerly of the three mountain ranges which the pipeline crosses on its route from Prudhoe Bay to the Port of Valdez. The vibrations could, on occasion, be detected by residents living near the pipeline at the bottom of the pass. Close to the source of the phenomena, small bushes could be seen moving in response to the seismic shocks and a noise similar to “mortars firing in the distance” could be heard.
Alyeska Pipeline Service Company initiated an extensive investigation and quickly determined that the seismic shocks were a result of pressure pulses originating near the slackline-packline interface. This only occurred when the slackline-packline interface was positioned near a terraced portion of the pipeline topography on the downstream side of the pass. This knowledge allowed Alyeska Pipeline to control the pulsations by backpressuring the pipeline and moving the slackline-packline interface well above the terrace location.
Effect of Flow Conditioners and Pulsation on the Performance of 8 Inch Multi-Path Ultrasonic Meters
Authors: Karnik U. , Studzinski W. , Geerligs J. , Rogi M. 
Published: October 2016

The performance of two 8inch multi-path ultrasonic meters provided by Instromet and Daniel Industries is evaluated in the presence of a 19 tube bundle and the CPACL’ flow conditioner. These flow conditioners are placed downstream of a single elbow and two elbows out of plane. The ultrasonic meters are tested at several locations downstream of the flow conditioners. NOVA’s gravimetric meter prover is used to evaluate the performance of the meters. The present measurements indicate that the use of CPACL flow conditioner results in a near baseline performance of ultrasonic meters.
The two meters were also tested for pulsation effects using some of the solutions suggested by the manufacturers. Present tests indicate that the solutions were not effective enough and the meters are subject to errors when exposed to a pulsating flow.
Early Public Notification
Authors: Ford Douglas V. 
Published: October 2016

In response to public pressure and in a desire to ensure that the public was adequately informed about potential projects, the National Energy Board (NEB) produced a Memorandum of Guidance with respect to its expectations regarding its Early Public Notification (EPN) program in 1990.
Over time, issues such as Stress Corrosion Cracking, Risk Assessment, Pipeline Integrity and Landowner Compensation have all significantly impacted the way companies have adjusted their approaches to the delivery of EPN programs.
In the future, the pipeline industry can expect that public consultation programs will increasingly become an essential component on both project specific and long range strategic communications planning. The purpose of this paper is to review the development and implementation of the EPN process and to propose future issues which may impact the planning and execution of consultation programs. The focus of this paper will be to:
A. Profile the evolution and delivery of EPN programs and review the communications tools typically used with EPN programs;
B. Examine the recent emergence of regional landowner interest groups and to review their effect on the regulatory process and issues such as pipeline integrity, pipeline safety and environmental stewardship;
C. Review how the pipeline industry has responded to public, Board and government initiatives regarding intervenor funding, and;
D. Provide insight into future EPN delivery systems as well as emerging trends with respect to public participation in the pipeline and resource sector.
Building a 5000hp, VFD Controlled, Pump Station in 105 Days: “Fact or Fantasy”
Authors: Spencer Roy C. , Grainger Lance G. , Peacock Vince G. , Blois Jon 
Published: October 2016

On March 17, 1997 Robicon Corporation was requested, by a large Alberta based oil company, to provide a proposal to manage a turn-key, crude oil, pump station project. The oil company had identified an immediate need to expand their North Eastern Alberta Pipe Line system to allow a higher thru-put into the Hardisty, Alberta area:
• the pipe line was capacity restricted and customer demand indicated an immediate requirement to increase pipe line thru-put by 70%;
• the capacity increase was required by June 30th or earlier.
Same Yet Different: A Comparison of Pipeline Industries in Canada and Australia
Authors: Jaques Susan 
Published: October 2016

Canada and Australia are remarkably similar countries. Characteristics such as geography, politics, native land issues, and population are notably similar, while the climate may be considered the most obvious difference between the two countries. The pipeline industries are similar as well, but yet very different in some respects too. This presentation will explore some of the similarities and differences between the pipeline industries in both countries.
The focus of the discussion will be mainly on long-distance, cross-country gas transmission pipelines. The author of this paper spent 4 years working for TransCanada PipeLines in Calgary in a pipeline design and construction capacity, and has spent 2.5 years working for an engineering consultant firm, Egis Consulting Australia, in a variety of roles on oil and gas projects in Australia.
Topics to be addressed include the general pipeline industry organisation and the infrastructure in both countries. The history of the development of the pipeline industry in each country provides insight as to why each is organised the way it is today. While neither system is “better” than the other, there are certain advantages to Canada’s system (nationally regulated) over Australia’s system (currently state-regulated).
The design codes of each country will be compared and contrasted. The pipeline design codes alternate in level of detail and strictness of requirements. Again, it cannot be said that one is “better” than the other, although in some cases one country’s code is much more useful than the other for pipeline designers.
Construction techniques affected by the terrain and climate in each country will be explored. Typical pipeline construction activities are well known to pipeliners all over the globe: clear and grade, trench, string pipe, weld pipe, coat welds, lower in, backfill and clean up. The order of these activities may change, depending on the terrain and the season, and the methods of completing each activity will also depend on the terrain and the season, however the principles remain the same. Australia and Canada differ in aspects such as climate, terrain and watercourse type, and therefore each country has developed methods to handle these issues.
Finally, some of the current and future opportunities for the 21st century for the pipeline industry in both countries will be discussed. This discussion will include items such as operations and maintenance issues, Canada’s northern development opportunities, and Australia’s national gas grid possibilities.
An Experimental Evaluation of Critical Buckling Strain Criteria
Authors: Dorey Alfred B. , Murray David W. , Cheng J. J. Roger 
Published: October 2016

In the past, a significant amount of investigation into the development of critical buckling strain limit state criteria for pipelines has been conducted and a number of critical strain criteria have been proposed. However, the availability of comparative experimental data that have been collected under representative pipeline operating conditions has been somewhat limited.
Over the past eight years, more than 50 full-scale pipeline tests under representative field conditions have been conducted at the University of Alberta (U of A) in Edmonton, Alberta, Canada. Experimental parameters have included the diameter-to-thickness (D/t) ratio, the internal pressure to yield pressure ratio (p/py), and the presence or absence of a circumferential girth-weld at the mid-height of the specimen. Critical strain values were determined for the majority of these test specimens and were then compiled in an attempt to assess current limit state design criteria for governing critical buckling strains.
This paper summarizes the critical buckling strain values from a total of 38 tests that have been conducted at U of A at the present time. The experimental results are then used to assess a number of previously developed critical strain criteria.
Planning for Purging and Loading of a Newly Constructed Gas Pipeline System Using a Pipeline Simulator
Authors: Mohitpour Mo , Kazakoff J. , Jenkins Andrew , Montemurro David 
Published: October 2016

Purging of a gas pipeline is the process of displacing the air/nitrogen by natural gas in an accepted constant practice in the natural gas pipeline industry. It is done when pipelines are put into service. Gas Pipelines are also purged out of service. In this case they are filled with air or other neutral gases.
Traditionally, “purging” a newly constructed pipeline system is carried out by introducing high pressure gas into one end of the pipeline section to force air out of the pipeline through the outlet until 100% gas is detected at the outlet end. While this technique will achieve the purpose of purging air out of the pipeline, it gives little or no consideration to minimizing the emission of methane gas into the atmosphere.
With the advances of the pipeline simulation technology, it is possible through simulation to develop a process to minimize the gas to air interface and thereby minimize the emission of methane gas. In addition, simulation can also be used to predict the timing of purging and loading of the pipeline. Therefore, scheduling of manpower and other activities can be more accurately interfaced.
In this paper a brief background to purging together with a summary of current industry practices are provided. A simplified purging calculation method is described and a simulation technique using commercially available software is provided for planning purging and loading operations of gas pipeline systems. An Example is provided of a recently constructed pipeline (Mayakan Gas Pipeline System) in Mexico to demonstrate how the planning process was developed and carried out through the use of this simulation technique. Simulation results are compared with field data collected during the actual purging and loading of the Mayakan Pipeline.