{"operation":"document","citation":"PI-86-004","title":"Public Service Commission — Pipeline Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"1986-07-24","effective_on":null,"summary":"PI-86-004 response to Public Service Commission concerning 192.467.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-86-004.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-86-004.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-86-004","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/Pipeline/1986/PI86004.pdf","body":"<<<PAGE 1>>>\n\nJuly 24, 1986\nMr. E. Scott Smith\nChief Engineer\nPublic Service Commission\n730 Schenkel Lane\nPost Office Box 615\nFrankfort, Kentucky 40602\nDear Mr. Smith:\nYour letter of June 17, 1986, asks, \"should a distribution company have a specific program\nwhereby the inspection and electrical test of cased road crossings on cathodically protected lines\nwould be conducted annually, or can compliance with the 192.467(c) and (d) be achieved by\ncomplying with 192.465(a), even though test stations are not always located at the cased\ncrossings and test of the bare casing is not taken?\"\nWhen properly conducted the testing under §192.465(a) would also establish compliance with\n§192.467(c) and (d).\nSection 192.465(a) states \"Each pipeline that is under cathodic protection must be tested at least\nonce each calendar year, but with intervals not exceeding 15 months, to determine whether the\ncathodic protection meets the requirements of §192.463....\" The tests under §192.465(a) must be\nsufficient to determine whether the cathodic protection meets the requirements of §192.463 for\nthe entire pipeline, including any cathodically protected segments inside casings. If the tests under\n§192.465(a) show that the cathodic protection of a cased segment is adequate, then §192.467(d)\nhas been satisfied because the electrical isolation must also be adequate, and compliance with\n§§192.467(a) and (c) has been achieved. If §192.465(a) tests show inadequate protection of any\ncased segment, then additional inspection and tests would be needed under §192.467(d) to\ndetermine the adequacy of electrical isolation.\nFor your information we are enclosing a copy of the \"Regulation Enforcement Guidelines\" for\n§192.467 that was prepared by OPS enforcement staff in 1983.\nSincerely,\nRichard L. Beam\nAssociate Director\nPipeline Safety Regulation\ndal\\192\\467\\86-07-24\n1\n\n<<<PAGE 2>>>\n\nREGULATION ENFORCEMENT GUIDELINES\n192.467 EXTERNAL CORROSION CONTROL: ELECTRICAL ISOLATION\nElectrically shorted casing\n1. A violation of Paragraph 192.467(c) exists if:\nA cathodically protected transmission or distribution pipeline, other than unprotected\ncopper inserted into ferrous pipe, is electrically connected to metallic casings that are a\npart of the underground system and within six months of discovery of the electrical short\nbetween the casing and pipeline, the operator has not initiated corrective action in\naccordance with Paragraph 3 below. Discovery shall be presumed upon conduct of on\n[sic] electrical survey with results as described in Paragraphs 2(a) and 2(b).\nThe operators Operation and Maintenance Plan should also be investigated to:\nA. determine that the operator has a procedure to per 192.605, and;\nreact to shorted casings\nB. follows that procedure per 192.13(c)\n2. Evidence of violation - Paragraph 192.467(c):\nA. Documentation and dates of pipe-to-soil potential surveys made pursuant to\nSection 192.465 that show pipe-to-soil and adjacent casing-to-soil potentials to be\nessentially the same, indicating an electrical short between casing and pipe.\nB. Documentation and dates of casing-to-soil potential measurements which are more\nnegative than normal, but not as negative as adjacent pipe-to-soil potential\nmeasurements, indicating a \"partial\" electrical short between casing and pipe.\nNotes:\nA zero resistant short, as in (a) prevents cathodic protection from reaching the\npipeline inside the casing and thus prevents the operator from complying with\nParagraphs 192.455(a)(2), and 192.457(a) for those pipe sections.\nA \"partial\" short, as in (b) reduces the amount of cathodic protection current to the\npipeline. It is not practical to determine the degree of protection\nreceived by the pipe inside a \"partially\" shorted casing for compliance with\nParagraph 192.463(a).\ndal\\192\\467\\86-07-24\n2\n\n<<<PAGE 3>>>\n\nC. Field checks:\ni). At locations where pipe-to-soil and adjacent casing-to-soil measurements are\nessentially the same, the presence of an electrical short can be readily\nchecked by connecting one output terminal of pipe locator transmitter to\nthe pipeline and the other to the casing (this utilizes the conductive mode).\nThen move the receiver out to a point over the pipeline about 50 to 100\nfeet away from the casing. If no signal is picked up, the casing is shorted\nto the pipe. Also, determine if connecting test leads from casing and pipe\ntogether has any effect on signal strength. It should not. However, there\nwill be a change in signal strength if the casing is partially shorted to the\npipeline.\nii). Have operator interrupt rectifier located some distance away from shorted or\npartially shorted casing; at least a mile away would be preferable. If it has\nto be closer, be sure that casing pipe at point of measurement is not within\nthe voltage gradient of the rectifier groundbed.\nThese interrupted voltage checks will serve to verify the presence of a\nshort or partial short between casing and pipe.\nD. Operator records:\nA. Pipe-to-soil and casing-to-soil potential measurements should be retained\nby the operator in accordance with Paragraph 192.491(b)(2).\nE. Operator's O&M Plan:\nA. To comply with the requirements of Sections\n192.467(c), 192.453, and 192.605, the operator's O&M Plan must\nincorporate procedures to be used for correcting or negating the adverse\neffects of shorted casings. Then, consistent with Paragraph 192.13(c), the\noperator is to follow the procedures that it has established.\ndal\\192\\467\\86-07-24\n3\n\n<<<PAGE 4>>>\n\n3. Reasonable time allowance and method for operator's correction of shorted casings:\nA. After the cathodic protection survey has been completed and a shorted\ncasing has been identified, the operator should determine a course of action intended\nto correct or negate the adverse effects of shorted casings. The\noperator's plan of action should be initiated within six months of completion of\nthe survey and should include one of the following options:\ni). Clear the short if practical;\nii). Fill the casing/pipe interstice with high dielectric casing filler or other material which\nprovides a corrosion inhibiting environment.\niii). If options i or ii would be impracticable and, if in the judgement of the operator the risk of\ncorrosion is minimized by conditions including the location and condition of the\npipe, the risk of overpressure, and environmental factors, the operator may choose\nto monitor the casing with leak detection instruments at intervals not exceeding the\nrequirements of 192.705 and 192.721 until such time as options i or ii become\npracticable or conditions change which render option iii inadequate to minimize the\nrisk of corrosion.\nIf the operator chooses to monitor the shorted casing with leak detection\ninstruments, immediate corrective action must be taken if and when a leak is\ndiscovered. A corrosion leak is a condition that would render option iii\ninadequate.\nE. In connection with the use of inhibitors in the water between shorted casing and\npipe, the operator should demonstrate that galvanic currents cannot flow.\nOtherwise, corrosion will take place.\nIf the inhibitor is effective, the operator should also be able to demonstrate by\nperiodic sampling that the inhibitor will stay in the casing/pipe interstice without\nleaching out the ends into the soil during low water tables.\ndal\\192\\467\\86-07-24\n4\n\n<<<PAGE 5>>>\n\n4. Road and Railroad casings are in areas where continuing considered to be detrimental to public safety.\npipeline corrosion is\nA. The OOE Pipeline Safety Enforcement Manual, page 14d (Rev. 1/19/81),\nunder Part D relative to definition and enforcement guidelines for\nParagraph 192.457(c), provide the following guide material:\n\"In order to achieve uniform enforcement policy, all regions should\nconsider continuing corrosion occurring in the following areas to be\ndetrimental to public safety (active corrosion):\n1. . . .\n2. . . .\n3. 4. . . .\nAt highway and railroad crossings.\nB. Thus, all highway and railroad crossings involving cathodically protected\ngas pipelines must be electrically isolated from the casing, or other\nmeasures must be used to miticate [sic] or monitor galvanic corrosion of\nthe pipeline inside the shorted casings.\n5. General notes:\nA. To cathodically protect a pipeline means to cathodically protect it in its\nentirety. It should be noted that a pipeline is not protected in its entirely, as\nrequired by 192.455 or 192.457, whenever casings are shorted to the\npipelines because of the shielding effect of the casings that prevents\ncathodic protection current from reaching the pipeline inside the casing.\ndal\\192\\467\\86-07-24\n5\n\n<<<PAGE 6>>>\n\nCOMMONWEALTH OF KENTUCKY\nPUBLIC SERVICE COMMISSION\n730 SCHENKEL LANE\nPOST OFFICE BOX 615\nFRANKFORT, KY 40602\n(502) 564-3940\nJune 17, 1986\nMr. Richard L. Beam, Director\nOffice of Pipeline Safety Regulation\nMaterials Transportation Bureau\n400 Seventh Street, S.W.\nWashington, D.C. 20590\nDear Mr. Beam:\nColumbia Gas of Kentucky, Inc. (Columbia) is an intrastate natural gas distribution\ncompany and is jurisdictional to this Commission through our 5a agreement. While conducting a\ncomprehensive inspection of one of its districts, our inspector discovered that Columbia does not\nhave a specific program of inspecting and electrically testing carrier pipe at cased crossings or the\ncasing to assure that it is not shorted or partially shorted.\nTo comply with 192.467(c) and (d), it appears that specific tests must be conducted at\nthese locations on a periodic (annual) basis.\nThis is a request for interpretation of the following regulations:\n49 CFR 192.467(a) states:\n\"Each buried or submerged pipeline must be electrically isolated from other underground\nmetallic structures, unless the pipeline and the other structures are electrically\ninterconnected and cathodically protected as a single unit.\"\n49 CFR 192.467(c) states:\n\"Except for unprotected copper inserted in ferrous pipe, each pipeline must be electrically\nisolated from metallic casings that are a part of the underground system. However, if\nisolation is not achieved because it is impractical, other measures must be taken to\nminimize corrosion of the pipeline inside the casing.\"\ndal\\192\\467\\86-07-24\n6\n\n<<<PAGE 7>>>\n\n49 CFR 192.467(d) states:\nadequate.\"\n\"Inspection and electrical tests must be made to assure that electrical isolation is\nShould a distribution company have a specific program whereby the inspection and\nelectrical test of cased road crossings on cathodically protected lines would be conducted\nannually, or can compliance with the 192.467(c) and (d) be achieved by complying with\n192.465(a), even though test stations are not always located at the cased crossings and test of the\nbare casing is not taken?\nSincerely,\nE. Scott Smith, Chief Engineer\ndal\\192\\467\\86-07-24\n7","truncated":false,"body_characters":10745}