{"operation":"document","citation":"PI-75-060","title":"Mountain Fuel Supply Company — Pipeline Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"1975-12-31","effective_on":null,"summary":"PI-75-060 response to Mountain Fuel Supply Company concerning 192.505.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-75-060.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-75-060.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-75-060","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/Pipeline/1975/PI75060.pdf","body":"<<<PAGE 1>>>\n\nDecember 31, 1975\nMr. F. F. Bassani\nMountain Fuel Supply Company\n625 Connecticut Avenue\nRock Springs, WY 82901\nDear Mr. Bassani:\nThis is in response to your request for an interpretation of Section 192.505. You asked, \"After\nperforming a hydrostatic test of a portion of a new pipeline to 125 percent of M.A.O.P., would it\nthen be permissible to conduct a pressure test of a section of a new pipeline, which includes the\nabove-mentioned section hydrostatically tested, to a test pressure near 80 percent of SMYS using\nnatural gas as the testing medium?\" Your letter states that the section to be hydrostatically tested\nis located within 300 feet of four houses and the entire pipeline to be tested is in a Class 1\nlocation.\nAs Lloyd Ulrich of our Office notified you by telephone on December 2, 1975, Section 192.505\nimplicitly prohibits a test with natural gas to a hoop stress of 30 percent or more of SMYS in a\nClass 1 or Class 2 location where buildings intended for human occupancy are located within 300\nfeet of a pipeline. In such locations, Section 192.505 requires a hydrostatic test to a level of at\nleast 125 percent of maximum operating pressure. However, if the buildings are evacuated while\nthe hoop stress exceeds 50 percent of SMYS, air or inert gas may be used as the test medium.\nNatural gas is not included in Section 192.505 as an allowable test medium to protect the public\nwhere buildings intended for human occupancy are located within 300 feet of a pipeline.\nFurther, as indicated by Mr. Ulrich, the highest stress allowed in the pipeline at such a location as\ndescribed above while it contains natural gas is 72 percent of SMYS, and that stress is allowed\nonly when that segment of the pipeline has been successfully tested hydrostatically to a minimum\nof 90 percent of SMYS. A test to that stress level would qualify that segment of the pipeline to\noperate at a stress level of 72 percent of SMYS in a Class 1 location. Since 125 percent of 72\npercent is 90 percent, the test would also satisfy the requirement in Section 192.505 concerning\ntesting so at least 125 percent of maximum\ndal\\192\\505\\75-12-31\n1\n\n<<<PAGE 2>>>\n\noperating pressure where buildings for human occupancy are located within 300 feet of the\npipeline.\nI trust this answers your question. Thank you for your interest in pipeline safety.\nSincerely,\nCesar DeLeon\nActing Director\nOffice of Pipeline\nSafety Operations\ndal\\192\\505\\75-12-31\n2","truncated":false,"body_characters":2445}