2.1 Overview of the Proposed Project - Keystone XL pipeline - US ...

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Draft Supplemental Environmental Impact StatementKeystone XL ProjectThe design parameters for steel pipe would be determined in accordance with the followingequation (see 49 CFR 195.106—Internal Design Pressure):P=(2*S*t/D)*E*Fwhere:P=Internal design pressure in psi (kPa 3 ) gageS=Yield strength in pounds per square inch (kPa)D=Nominal outside diameter of the pipe in inchest=Nominal wall thickness of the pipe in inchesF=Design factorE=Seam joint factorThe design factor (F) would be determined as a result of conditions or a combination ofconditions such as crossings, fabrications, station piping, and special areas. The design factor of0.72 would be used for the main line in all areas where normal installation methods and crosscountry conditions prevail with exceptions to areas as stipulated in the PHMSA SpecialCondition 14 such as pump station and IMLV facilities. A special permit would be required fromPHMSA if the pipeline were to operate using a higher design factor. In this situation, PHMSApermit conditions would provide an equivalent or better level of safety. Line pipe for theproposed Project would be double submerged arc welded in accordance with API 5L Steel Pipe,44th Edition (TC 2012). Key design parameters applicable to the proposed Project pipeline arelisted in Table 2.1-12.Table 2.1-12Pipe Design Parameters and SpecificationPipe Design ParametersSpecificationMaterial codeAPI 5L-PSL2-44th EditionMaterial grade thousand pounds of pressure Grade X70per square inch (psi) (yield strength) aMaximum pump station discharge1,308 pounds per square inch gauge (psig)Maximum Operating Pressure1,308psig; 1,600 psig aIn conformance with Special Conditions 8 and 22, the pipe mustbe subjected to a mill hydrostatic test pressure of 95% SMYS b orgreater for 10 seconds and the pre-in service hydrostatic test mustbe to a pressure producing a hoop stress of a minimum 100%SMYS for mainline pipe and 1.39 times maximum operatingpressure for pump stations for 8 continuous hours. The hydrostatictest results from each test must be submitted in electronic formatMinimum hydrostatic test pressureto the applicable PHMSA Director(s) in PHMSA Central.Joint length (feet)Nominal 80-foot (double-joint)Mechanized―gas metal; arc welding; manual-shielded metal arcField production welding processes welding.Pipeline design code 49 CFR Part 195Outside diameter36 inchesLine pipe wall thickness () 0.72 design factor as per 49 CFR 195.1063 KPa is a common multiple unit of the Pascal (1 kPa ≡ 1000 Pa).Project Description 2.1-36 March 2013
Draft Supplemental Environmental Impact StatementKeystone XL ProjectPipe Design ParametersStandard wall thickness – mainlineHeavy wall thickness―HCAs including,high population areas, other populatedareas, unusually sensitive areas, includingdrinking water and ecologically sensitiveareas, mainline valve and pump stationsites.Heavy wall thickness—directly downstreamof pump stations at lower elevations asdetermined by steady state and transienthydraulic analysis aHeavy wall thickness―uncased road andcased railway crossingsHeavy wall thickness―uncased railwaycrossings, HDDs aSource: TC 2012.Specification0.465 inch0.515 inch0.572 inch0.618 inch0.748 inchaThe design of the proposed Project pipeline system is based on a maximum 1,308 pounds per square inch gauge (psig) dischargepressure at each pump station. The pump station discharge pressure would be a maximum of 1,308 psig. There would besituations where, due to elevation changes, the hydraulic head created would result in a maximum operating pressure of up to andincluding 1,600 psig. Suction pressure at the pump stations is generally on the order of 200 psig.bSMYS = specified minimum yield strength.Keystone has stated that approximately 95 percent of the pipe for the U.S. portion of theproposed Project would be purchased from North American pipe manufacturing facilities andthat regardless of the country of origin, it would purchase pipe only from qualified pipe suppliersand trading houses. Qualification includes comprehensive evaluations of manufacturingfacilities, extensive technical discussions with the lead quality control and metallurgy personnel,and a clear demonstration that the mills can meet the requirements to produce and test pipe inaccordance with Keystone’s standards and specifications 4 .To protect against corrosion, an external coating (fusion-bonded epoxy [FBE]) would be appliedto the pipeline and all buried facilities, and cathodic protection (CP) would be applied to thepipeline by impressed current. These measures would be provided in compliance with 49 CFR195, Subpart H (Corrosion Control) and the requirements of 14 of the PHMSA 57 SpecialConditions (see Appendix B). CP is a technique used to control the corrosion of a metal surface.The simplest method to apply CP is by connecting the metal to be protected with a piece ofanother more easily corroded "sacrificial metal" to act as the anode of the electrochemical cell.The sacrificial metal then corrodes instead of the protected metal. CP systems are used to protecta wide range of metallic structures in various environments, from fuel pipelines to home waterheaters. In the usual application, a galvanic anode (a piece of a more electrochemically "active"metal) is attached to the vulnerable metal surface where it is exposed to the corrosive liquid.Galvanic anodes are designed and selected to have a more “active” voltage (more negativeelectrochemical potential) than the metal of the target structure (typically steel).Pipelines are routinely protected by a coating supplemented with CP. A CP system for a pipelinewould consist of a direct current (DC) power source, which is often an alternating current (AC)4 Keystone would use TransCanada Pipelines’ pipe specifications for the proposed Project where those specificationsexceed federal regulations and the PHMSA Special Conditions.Project Description 2.1-37 March 2013
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