{"operation":"document","citation":"PI-03-0102","title":"City of Mesa — Pipeline Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"2003-06-11","effective_on":null,"summary":"PI-03-0102 response to City of Mesa concerning 192.747.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-03-0102.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-03-0102.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-03-0102","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/Pipeline/2003/g03-06-11_Comstock_192.747-msfx.pdf","body":"<<<PAGE 1>>>\n\nPI-03-0102\nU.S. Department of Transportation\nResearch and Special Programs Administration\nJune 11, 2003\nMr. Michael Comstock\nUtility Compliance Coordinator\nCity of Mesa\n640 North Mesa Drive P.O. Box 1466\nMesa, AZ 85211-1466\nDear Mr. Comstock:\nThis is in response to your September 19, 2001, request for an interpretation of the distribution valve\nmaintenance regulation at 49 CFR 192.747. You ask whether a \"gas valve used to control blowing or escaping natural gas\nbecomes a 'Key Valve,' and as a 'Key Valve,' requires special treatment for the life of the valve.\"\nSection 192.747, Valve Maintenance: Distribution Systems, states that \"[e]ach valve, the use of which may be\nnecessary for the safe operation of a distribution system, must be checked and serviced at intervals not exceeding 15\nmonths, but at least once each calendar year.\"\nThis section addresses the maintenance of valves which may be necessary to safely operate the distribution\nsystem and to isolate parts of the system as necessary. In response to this regulation and safe operating practices, the\nCity of Mesa has designated many, but not all, distribution system valves as \"Key Valves.\"\nMere operation of a particular valve during an emergency does not automatically elevate it to \"Key Valve\" status\nwithin the meaning of § 192.747. Many valves may be shut during an emergency, including designated \"Key Valves,\"\nvalves on service lines, valves at the meter assembly, and even some mainline valves not designated as \"Key Valves.\" Not\nall of these valves, upon investigation, would necessarily be shown to be \"necessary for the safe operation of the\nsystem.\"\nThe question to be addressed is whether a particular valve is necessary on an ongoing basis to safely operate the\ndistribution system. This question must be addressed on a case by case basis by the distribution company and its\nregulatory agencies. Therefore, a \"gas valve used to control blowing or escaping natural gas at an accident site\" does not\nautomatically become a \"Key Valve.\"\nIf you have any further questions about the pipeline safety regulations, please contact me at (202) 366-4565.\nSincerely,\nRichard D. Huriaux, P.E.\nManager, Regulations\nOffice of Pipeline Safety\n\n<<<PAGE 2>>>\n\nCity of Mesa\nUtilities Department\nRegulatroy Affairs Section\n640 North Mesa Drive\nP.O. Box 1466\nMesa, Arizona 85211-1466\nOctober 30, 2002\nRichard D. Huriaux\nManager, Regulations\nOffice of Pipeline Safety\nU.S. Department of Transportation\n400 Seventh Street, S.W.\nWashington, D.C. 20590\nRE: Interpretation Request, Valve Maintenance: Distribution Systems 192.747\nDear Mr. Huriaux:\nOn September 19, 2001, the City of Mesa, Arizona, submitted to your office a request for interpretation on the above\nreferenced matter. To date, the City has not received a response to the interpretation request.\nI have enclosed a copy of the original interpretation request for your review and information. If you have any questions\nor a need for further information, please feel free to call me at 480-644-2490 or contact me at:\nMichael_Comstock@cimesa.az.us.\nSincerely,\nMichael Comstock\nRegulatory Affairs Coordinator\nCity of Mesa, Arizona\n\n<<<PAGE 3>>>\n\nCity of Mesa\nUtilities Department\nRegulatroy Affairs Section\n640 North Mesa Drive\nP.O. Box 1466\nMesa, Arizona 85211-1466\nSeptember 19, 2001\nRichard D. Huriaux\nManager, Regulations\nOffice of Pipeline Safety\nU.S. Department of Transportation\n400 Seventh Street, S.W.\nWashington, D.C. 20590\nRE: Interpretation Request, Valve Maintenance: Distribution Systems 192.747\nDear Mr. Huriaux:\nThe City of Mesa, Arizona (COM) is requesting an interpretation from the Office of Pipeline Safety on Title 49 Code of\nFederal Regulations (49CFR), Part 192, Subpart 747, Valve Maintenance: Distribution Systems.\nBackground\nAs do all Natural Gas Utilities, COM installs natural gas valves within its natural gas distribution system to control the\nflow of natural gas under a variety of situations-- operations, maintenance, and/or emergency response procedures (49\nCFR 192.181). The natural gas system in Mesa is divided into three distinct regimes of operation—high pressure,\nintermediate pressure, and low pressure delivery. We designate our \"High Pressure System\" (HP) as comprised of all\npipeline facilities that operate at a pressure greater than 60 psig. This includes the 150 psig and 250 psig loops that\nmaintain a high pressure feed to the district regulating stations. We designate our \"Intermediate Pressure System\" (IP)\n(usually installed with polyethylene plastic) as pipeline facilities that operate at 60 psig or less. This system includes all\ndelivery of natural gas to a customer service line regulator where the natural gas pressure is further reduced to the\ncustomer delivery pressures (usually seven inches of water column). The \"Low Pressure System\" (LP) operates at\ndelivery pressures. This system is very limited and includes only the pipeline facilities downstream of the customer's\nregulator, to the outlet swivel of the gas meter.\nThe City of Mesa has identified a number of distribution system valves as \"Key Valves\" in accordance with 49 CFR\n192.747 (See Attachment B, City of Mesa, Operations, Maintenance, Emergency Response and Construction Practices\nManual, Part 2, Subpart 1.1). These key valves are maintained as required in 49 CFR 192.747.\nAttachment A is a typical new subdivision map (plat), which shows the types of natural gas valves installed, their location\non the pipeline facilities, the size of natural gas line the valves etc. The HP system is designated in yellow highlight, the\nLP in blue. No low pressure is shown on this drawing.\nCurrent Situation\nCOM believes there should be valves in the natural gas system designated for system isolation and be maintained every\n12 months (An isolation plan). We also believe the best course of action, and often the safest and most expedient\nmethod of controlling a natural gas emergency, is the use of natural gas valves.\n\n<<<PAGE 4>>>\n\nCurrently, the State of Arizona's Corporation Commission has requested Mesa to:\n• Each time a valve is used to control a natural gas emergency, regardless of its designation, \"operating or emergency\"\n[192.181(0], it must be added to the City of Mesa's Key Valve List for continued annual maintenance for the life of the\nvalve.\nIn other words, any valve that is used during an emergency must then become a \"Key Valve\" and remain a key valve for\nthe life of the system.\nMesa believes that it is not the intent of 49 CFR Part 192, for ALL valves in a distribution system (a mainline valve, a\nservice line valve, or a metercock) to be designated as a \"key gas valve\" just because they happened to be used to\ncontrol escaping natural gas. Some valves in a distribution system may be used only once and never be used again.\n(Please note the following two scenarios).\n1. At the start of subdivision construction, the probability for damage to a natural gas main or service line is high,\nand a valve may be used to isolate a hit line rather than squeezing off a plastic main or service line. Simply\nstated, it is safer to isolate a blowing gas line via a valve then jumping into a trench and squeezing off the gas\nline. This is especially useful when there are few customers affected by the valve closure. This situation would\ncause all valves used at that time to be classified as \"Key\" Valves even though, from that point on, they may\nnever be operated again, except as part of a normal valve maintenance program.\n2. A recent fire occurred at a local supermarket behind the building. Several young boys started the fire by lighting\nwood pallets that were resting against the gas meter. The meter eventually melted and the gas ignited. The\nCity's crews responded promptly and shut off a nearby gas valve on the service line feeding the supermarket\ncomplex. Previously the valve was not considered a key valve.\nUnder the current interpretation, that valve, which was used just once, will remain a key valve forever. We do not\nbelieve it was ever the intent of the code to consider every valve a key valve and would like your interpretation.\nRequest of Interpretation\nConsidering the above issue and the examples provided: Does a gas valve used to control blowing or escaping natural\ngas become a key valve forever, and as a key valve, require special treatment under 49 CFR 192.747 for the life of the\nvalve.\nThank you in advance for your consideration in this matter. If you have any questions regarding this request, please feel\nfree to call me at 480-644-2490 or contact me at: Michael_Comstock@ci.mesa.az.us.\nSincerely,\nMichael Comstock\nUtility Compliance Coordinator\nCity of Mesa, Arizona","truncated":false,"body_characters":8667}