{"operation":"document","citation":"PI-76-048","title":"Louisiana Gas Service Company — Pipeline Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"1976-08-12","effective_on":null,"summary":"PI-76-048 response to Louisiana Gas Service Company concerning 192.179.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-76-048.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-76-048.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-76-048","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/Pipeline/1976/PI76048.pdf","body":"<<<PAGE 1>>>\n\nAug 12, 1976\nMr. D. L. Meriwether\nDirector of Technical Standards\nLouisiana Gas Service Company\nP.O. Box 433\nHarvey, Louisiana 70058\nDear Mr. Meriwether:\nThis responds to your letter dated May 10, 1976, requesting an interpretation of Title 49 CFR\nPart 192.179(c).\nQuestion: Where valves are installed at a closer interval than those as specified in 192.179(a),\nmust a blowdown be installed between each set of valves?\nAnswer: Yes, Section 192.179(c) states: \"Each section of a transmission line, other than offshore\nsegments, between main line valves must have a blowdown valve with enough capacity to allow\nthe transmission line to be blown down as rapidly as practicable. Each blowdown discharge must\nbe located so the gas can be blown to the atmosphere without hazard and, if the transmission line\nis adjacent to an overhead electric line, so that the gas is directed away from the electrical\nconductors.\"\nThe purpose of the pipeline blowdown valves are for exhausting gas from the line when required\nby repairs, emergencies, or other conditions.\nQuestion: Is there a guideline that determines the blowdown capacity for a certain size and length\nof pipeline?\nAnswer: Guidelines to determine blowdown capacity are not a function of this Office. Because\nthe issuing gas jet from a blowdown valve produces a violent reaction thrust, proper blowdown\ndesign is of major importance and is the responsibility of the operator. Blowdown valve sizes\nmay be selected by using various applicable formula and/or charts that are provided in handbooks\nsuch as the Gas Engineer's Handbook, or from valve manufacturers' literature.\nWe trust that this adequately responds to your inquiry.\nSincerely,\nCesar DeLeon\nActing Director\ndal\\192\\179\\76-08-12\n1\n\n<<<PAGE 2>>>\n\nOffice of Pipeline\nSafety Operations\nMay 10, 1976\nDepartment of Transportation\nMaterials Transportation Bureau\nOffice of Pipeline Safety Operations\n400 7th Street S.W.\nWashington, D.C. 20590\nGentlemen:\nWe would like to have an interpretation regarding Part 192.179(c) of Title 49 of the Code of\nFederal Regulations.\nWhere valves are installed at a closer interval than those as specified in 192.179(a), must a\nblowdown be installed between each set of valves? Rule 192.179(c) also states that the\nblowdown valve must have a capacity to allow the transmission line to be blown down as rapidly\nas practicable. Is there a guideline that determines the blowdown capacity for a certain size and\nlength of pipeline?\nAt your convenience, we would appreciate an interpretation of this regulation.\nYours very truly,\nLOUISIANA GAS SERVICE COMPANY\nD. L. Meriwether\nDirector of Technical Standards\ndal\\192\\179\\76-08-12\n2\n\n<<<PAGE 3>>>\n\ndal\\192\\179\\76-08-12","truncated":false,"body_characters":2711}