{"operation":"document","citation":"PI-93-056","title":"Minnegasco — Pipeline Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"1993-09-13","effective_on":null,"summary":"PI-93-056 response to Minnegasco concerning 192.201.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-93-056.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-93-056.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-93-056","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/Pipeline/1993/PI93056.pdf","body":"<<<PAGE 1>>>\n\nSeptember 13, 1993\nMr. Eugene F. Schultz\nMinnegasco\n6161 Golden Valley Road\nMinneapolis, MN 55422\nDear Mr. Schultz:\nYour letter of June 29, 1993, requests an interpretation of 49 CFR 192.201(c). You\nasked if it is acceptable to position a relief valve between two regulator stations located\nnear each other to protect the system from overpressure. The regulator stations both\nsupply low pressure gas to the same gas distribution system.\nThe configuration you describe may be acceptable. You must demonstrate that the\ncommon relief valve has the capacity to limit the maximum pressure in the main to a\npressure that will not exceed the safe operating pressure for any connected gas utilization\nequipment. The relief valve must have the capacity to protect the system if the largest\nvolume regulator station fails wide open. Pressure loss in the section of main between\neach of the two stations and the relief valve must be considered so that the pressure in the\nmain at each station complies with §192.201(a) (1). This could be a problem, particularly\nif the mains are old and have excessive accumulations of dirt, sediment, etc. Verification\nof relief valve capacity must also verify the absence of excessive pressure loss of this kind.\nWe trust that this responds satisfactorily to your request.\nSincerely,\nCesar De Leon\nDirector, Regulatory Programs\nOffice of Pipeline Safety\ndal\\192.201\\93-09-13","truncated":false,"body_characters":1412}