{"operation":"document","citation":"11-0046","title":"Chart Industries — Hazardous Materials Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"2011-04-18","effective_on":null,"summary":"11-0046 response to Chart Industries concerning 173.115, 173.320.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-11-0046.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-11-0046.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-11-0046","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretations/2011/110046.pdf","body":"<<<PAGE 1>>>\n\nU.S. Department of Transportation 1200 New Jersey Ave, SE\nWashington. D.C. 20590\nPipeline and Hazardous Materials\nSafety Administration\nAPR 1 8 2011\nMr. Dan Bricker\nChart Industries\n2800 Airwest Blvd.\nPlainfieJd, In. 46168\nReference No.: 11-0046\nDear Mr. Bricker:\nThis responds to your letter concerning the transport of cryogenic liquids under the Hazardous\nMaterials Regulations (HMR; 49 CFR Parts 171-180). Specifically, you ask how the definition\nof the term \"service pressure\" and the exceptions for cryogenic liquids provided in § 173.320 of\nthe HMR apply to specification DOT-4L welded insulated cylinders used to transport medical\noxygen. In your incoming letter, you state that you wish to transport medical oxygen in a 46\nLiter insulated liquid oxygen (LOX) container. Your questions have been paraphrased and\nanswered as follows:\nQ1: What is the definition of the term \"Service Pressure\" as it applies to the specification for\nDOT 4L welded insulated cylinders specified in § 178.57?\nAi: As specified in § 173.115, the term \"service pressure,\" as it is used throughout the HMR,\nmeans the authorized pressure marking on the packaging. For example, for a cylinder\nmarked \"DOT 3A1800,\" the service pressure is 12,410 kPa (1,800 psig). The 46 Liter\ninsulated LOX container you describe in your incoming letter cannot be considered a\nDOT-4L cylinder unless it has a water capacity (nominal) not over 1,000 pounds water\ncapacity, a marked service pressure of at least 40 psig but not greater than 500 psig, and\nthe cylinder conforms to all other specifications required in § 178.57.\nQ2: Does the 46 Liter insulated liquid oxygen (LOX) container described in the incoming\nletter meet the exceptions provided in § 173.320?\nA2: The packaging exceptions for cryogenic liquids are found in § 173.320 and allow for\nalternative packaging methods. In accordance with § 173.320(a), atmospheric gases and\nhelium, cryogenic liquids, in Dewar flasks, insulated cylinders, insulated portable tanks,\ninsulated cargo tanks, and insulated tank cars, designed and constructed so that the\npressure in such packagings will not exceed 25.3 psig under ambient temperature\nconditions during transportation are not subject to the requirements of this subchapter\n\n<<<PAGE 2>>>\n\nwhen transported by motor vehicle or railcar except as specified in paragraphs (a)(l),\n(a)(2), and (a)(3) of § 173.320. Provided your container meets the requirements of\n§ 173.320, it may be transported in the 46 Liter insulated liquid oxygen (LOX) container\nyou describe. It should be noted, however, that the 25.3 psig referred to in § 173.320(a)\nis not the service pressure.\nQ3: If the 46 Liter insulated liquid oxygen (LOX) container described in the incoming letter\ndoes not meet exceptions provided in § 173.320, what packaging specifications would the\ncontainer need to satisfy in order to transport cryogenic liquids?\nA3: The general requirements for cryogenic liquids in cylinders are found in § 173.316. If the\nmedical oxygen packaged in insulated LOX containers does not conform to the\nexceptions provided in § 173.320, it must be packaged in accordance with § 173.316 and\ntransported in a cylinder marked as a specification DOT-4L cylinder.\nI hope this satisfies your inquiry. Please contact us if we can be of further assistance.\nSincerely,\nT. Glenn Foster\nChief, Regulatory Review and Reinvention Branch\nStandards and Rulemaking Division\n\n<<<PAGE 3>>>\n\nc~\nCA I R E§\nMEMORANDUM\nTo: Mr. Duane Cassidy\nD.O.T. Chief of Approvals Group\nFROM: Dan Bricker\nDATE: 02/21/2011\nSUBJECT: Request for Guidance and Interpretation\nMr. Cassidy; Thanks for meeting with Ben Kadrlik and me on Friday. As you suggested I am making my\nrequest in writing. Please provide us with your guidance and interpretation with respect to the following:\n1. I would like a definition and better understanding ofthe term \"Service Pressure\" as it applies to 49\nCFR 178.57 specifications for DOT 4L welded insulated cylinders.\n2. Secondly, I would like to know the impact and intent of 173.320 Cryogenic Liquids; Exceptions\nunder the Requirements for Shipments and Packaging's.\nI am working on a 46 Liter insulated LOX container for providing medical oxygen to respiratory patients. In\nan effort to keep the service pressure under the 40 PSIG level which would place it within the 4L requirements\nI need to know specifically what is meant by the term \"service pressure.\" I have attached plumbing\nschematics of this unit in its Standby Mode and both oxygen delivery modes. When the unit is being used by\nthe patient, its normal operating pressure is 22 psig which is controlled by an \"economizer\" valve. If it is not\nbeing used by the patient such as when the patient is away with the mating portable unit, the system pressure is\ncontrolled by a primary relief valve. As a safety back-up to the primary reliefvalve, we then have a secondary\nrelief valve. I am assuming that the \"Service Pressure\" relates to the primary relief valve.\nMy thought is to have a service pressure under the 40 psig, and then consistent with CGA S-1.1 paragraph\n5.9.3, I would determine the primary relief valve setting as:\nSet pressure < (1.25 X 40) - 15, or 35 psig.\nAnother way to look at this may be that the normal operating pressure is 22 psig and if the vacuum loading of\n14.7 is added, then the service pressure would be 36.7 psia. This does not make sense because 178.57 defines\nthe service pressure limit as 40 psig.\nThe second question is related to the Requirements for Shipments and Packaging's, specifically part 173.320\nCryogenic Liquids; Exceptions paragraph (a). This states that cryogenic liquids in cylinders designed and\nconstructed so that the pressure will not exceed 25.3 psig during transportation are not subject to the\nrequirements of this subchapeter. In the case of the unit described above my assumption is that since the\npressure is in excess of the 25.3 psig (35 psig) then the it is subject to the requirements ofthe subchapter which\nfor a liquid oxygen cylinder would be specifically, 173.316 Cryogenic liquids in cylinders.\n\n<<<PAGE 4>>>\n\nSince the DOT 4L relates to the specification for the welded cylinders with service pressures> 40 psig and the\nrequirements for shipments and packagings has requirements for pressures exceeding 25.3 psig am I correctto\nassume that cylinders with pressures between these two references can be used to ship liquid oxygen without\nbeing DOT 4L stenciled providing thatthe requirements of 173.316 are met?\nStandard Reservoir Only ---\n.....\nGaseous O2\nStandby\n\n<<<PAGE 5>>>\n\nStandard Reservoir Only ---\"\"'l\nSRV\nEcon Valve\n22 psig\nGaseous O2\nLiquid O2\nOxygen Flow Through Economizer Circuit","truncated":false,"body_characters":6682}