{"operation":"document","citation":"PI-75-0107","title":"The Public Utilities Commission — Pipeline Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"1975-06-19","effective_on":null,"summary":"PI-75-0107 response to The Public Utilities Commission concerning 192.507, 192.553, 192.557, 192.619, 192.621, 192.623.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-75-0107.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-75-0107.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-75-0107","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/Pipeline/1975/g75-06-19_Richardson_192.507-msfx.pdf","body":"<<<PAGE 1>>>\n\nPI-75-0107\nJUN 19 1975\nMr. Ray A. Richardson\nState of Colorado\nThe Public Utilities Commission\n500 Columbine Building\n1845 Sherman Street\nDenver, Colorado 80203\nDear Mr. Richardson:\nThis responds to your letter of June 3, 1975, concerning the pressure test required in uprating to a pressure\npermitted by Section 192.619(a)(2)(ii) and the leak check required by Section 192.553(a)(1).\nWe believe the following excerpts from a recent interpretation by this Office answer your questions:\n\"Subject to the requirements of Section 192.621 or Section 192.623, as the case may be, the maximum\nallowable operating pressure for a pipeline may not be increased above the lowest pressure determined\nunder Section 192.619(a). For a steel pipeline operated at 100 psig or more, in uprating under Section\n192.557 to a pressure permitted by Section 192.619(a)(2)(ii), a pressure test must be performed under\nthat Section. Steel pipelines operated at less than 100 psig may be uprated under Section 192.557 to a\npressure permitted by Section 192.619(a) without conducting a pressure test. Where a pressure test is\nperformed in up rating under Section 192.557, the standards do not specify the nature of the test.\nHowever, the provisions of Section 192.507, applicable to tests on new or replaced or relocated pipe, can\nserve as a guide.\n\"In conjunction with uprating, Section 192.553(a)(1) requires incremental pressure increases to be held\nwhile the pipeline is checked for leaks. This leak check may be performed by survey, and there is no\nminimum time specified for holding the pressure.\"\nIf we may be of further assistance, please let us know.\nSincerely,\nORIGINAL SIGNED BY\nJoseph C.Caldwell\nDirector\nOffice of Pipeline Safety\n\n<<<PAGE 2>>>\n\nState of Colorado\nDepartment of Regulatroy Agencies\nThe Public Utilities Commission\n500 Columbine Building\n1845 Sherman Street\nDenver, Colorado 80203\nJune 3, 1975\nMr. Joseph C. Caldwell, Director\nOffice of Pipeline Safety\nDepartment of Transportation\nWashington, D.C. 20590\nDear Mr. Caldwell:\nA disagreement has arisen over some Federal Code interpretations in Colorado. Considerable confusion has\ndeveloped between our office and some gas operators as to understanding the Subpart K on \"uprating.\" Your\nconsideration and comments will be helpful.\nOur primary question is regarding the top test pressure one must elevate a pipeline segment to when raising\nthe MAOP by Uprating. Must the operator be governed by Paragraph 192.619(a)(2) safety factors (as based on\nclass locations) in determining the highest pressure to which he goes incrementally? We cannot find any\nreference or comments that .619 applies or does not apply to \"Uprating.\" For that matter we do not find any\n\"does or does not apply\" comments that the .619 factors apply to the Strength Testing Subpart J either.\nHowever, those factors are commonly accepted and used by the industry when strength testing a segment to\nestablish new MAOP's.\nEXAMPLE:\nAn operator wishes to raise an existing MAOP from 500psig to 700psig. May he simply raise it in four equal\nincrements of 50 psi never exceeding 700psig as a top pressure? Or, must he calculate a top test pressure\nrequirmment of lets say 1,000psig (depending on his class location factor from Paragraph .619(a)(2)) and then\nuse that 1,000psig as his top pressure which will mean he has a differential of 500psi (1,000 - 500psi). The\noperator would then divide the 500psi into four equal increments as test points. The top test pressure of\n1,000psig, would, of course, be held long enough to leak survey and make any repairs. We could then say he\nhad qualified his line at the 700psig MAOP level, which he desired orginally. Whichever method he uses, we\nmust assume he meets all other conditions and limitations of the uprating process such as max. hoop stresses\nduring testing.\nIt is interesting to note, both methods require only four incremental steps of pressure testing.\nThe possible disadvantages of applying the .619 factors and requiring the higher level of top pressure are\ntwofold. First, the operator very likely will find it more difficult and costly to impress the higher pressure upon\nthe segment of pipeline. Furthermore, his new MAOP might be limited to something less, using this method,\nthan he could obtain by the simpler procedure. If .619 does dictate what the top test pressure (last increment)\nwill be, the operator might not be able to run a test pressure that high because the max. design and hoop\nstresses will be exceeded.\nThe question boils down:to does the Code intend that class location safety factors apply to all methods of\ntesting to establish a new MAOP? We believe that to be the intention of the Code. When reading Paragraph\n\n<<<PAGE 3>>>\n\n192.619(a) as a MAOP establishing requirement, the only exception mentioned relates to Paragraph (c).\nThe second question regarding Uprating involves the Code's intended method of \"checking for Leaks\" as\nreferred to in Paragraph 192.553(a)(1). Is the operator obligated to test the segment at each incremental test\npressure point by instrumentation such as flame ionization and/or Combustible Gas Indicator, etc.? Some\noperators believe they can employ a visual method, listening and watching for leaks as they walk the segment\nkeeping close watch on the line static pressure to determine if any sudden or continual pressure drops\ndevelop.\nPossibly a combination of these things is acceptable where only at the last increment of pressure will the\nsegment be fully surveyed by instrumentation. The size, length, and location of the segment may also be\nfactors in the prudent determination of how the testing should be accomplished, during uprating.\nWill you please give our state office some comments and interpretations on these Code subjects? Your earliest\nresponse will be helpful and appreciated.\nVery truly yours,\nTHE PUBLIC UTILITIES COMMISSION OF THE STATE OF COLORADO\nRay A. Richardson\nGas Safety Engineer","truncated":false,"body_characters":5946}