{"operation":"document","citation":"10-0147","title":"CVA, Inc. — Hazardous Materials Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"2012-01-11","effective_on":null,"summary":"10-0147 response to CVA, Inc. concerning 173.316, 178.57.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-10-0147.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-10-0147.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-10-0147","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/2010/100147.pdf","body":"<<<PAGE 1>>>\n\nu.s. Department 1200 New Jersey Avenue SE\nof Transportation Washington. DC 20590\nPipeline and Hazardous\nMaterials Safety\nAd ministration\nMr. I. Keith Hall\nEngineering Manager\nCVA, Inc.\n9528 Warren Road\nP.O. Box 1230\nMont Belvieu, TX 77580\nReference No. 10-0147\nDear Mr. Hall:\nThis is in response to your e-mail and subsequent telephone conversations with members\nof my staff requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR\nParts 171-180) applicable to DOT Specification 4L welded, insulated cylinders. You state\nyour company wants to construct these cylinders to contain \"UN 1073, Oxygen,\nrefrigerated liquid (cryogenic liquid), 2.2 (non-flammable gas), 5.1 (oxidizer)\" that it will\ntransport by van motor vehicle for an in-home medical oxygen delivery service. We have\nparaphrased your questions and answered them in the order provided.\nQl. You ask if, under §§ 173.316(c) and 178.57, the cylinder may be constructed to\noperate in a horizontal instead of vertical position.\nAl. DOT 4L cylinders that contain cryogenic liquids, such as refrigerated liquid\noxygen, are required to be transported in the vertical position in conformance with\n§ 173.316(c). The HMR also requires that DOT 4L cylinder have openings in the\ncylinder head only (see § 178.57(h)(1)). Further, DOT 4L cylinders must also be\nequipped with one or more pressure relief devices that are installed and located so\nthe cooling effect of the cylinder contents during venting will not prevent the\ndevice from operating effectively (see § 173.316(a)(6) and (a)(7)). Although\n§ 178.57(p)(4) requires DOT 4L cylinders with openings at the top of the cylinder\nto be marked with special orientation instructions, such as \"THIS END UP\" when\nused in other than a vertical orientation, this section does not authorize the\ncylinder's construction in a non-vertical orientation. Therefore, to operate a DOT\n4L specification cylinder in the horizontal position, the cylinder's design, inc1uding\nits pressure relief system, must be authorized under the terms of a special permit.\nThe procedure for applying for a special permit can be found in 49 CFR Part 107,\nSubpart B, and can also be found on our website at ''http://www.phmsa.dot.gov/\nhazmat\" under \"Special Permits.\"\n\n<<<PAGE 2>>>\n\nFor pressure relief devices on cylinders that contain liquefied gases to operate\neffectively, it is the opinion of this Office that these devices must be designed and\ninstalled to operate within the inlet port located in the vapor space of the cylinder.\nIt is also the opinion of this Office that releasing compressed gas in liquid form\nthrough a cylinder's pressure relief device can create unsafe conditions in\ntransportation, such as; 1) an extremely flammable or toxic environment,\nrespectively, if the gas released is a Division 2.1 (flammable) gas or a Division 2.3\n(poisonous) material, or; 2) an asphyxiant environment if the released gas displaces\nthe normal concentration of oxygen in breathable atmosphere. Unsafe conditions\nspecific to released cryogenic liquefied oxygen include: 1) oxygen-enriched air and\nmaterials that can explosively combust and/or sustain burning if an ignition source\nis present; 2) extreme cold; and 3) explosion from rapid pressure rise if the cylinder\nis damaged in an accident, loses thermal protection, or is exposed to an external\nheat source such as fire. The Pipeline and Hazardous Materials Safety\nAdministration (PHMSA) will address the location of pressure relief devices in\npackagings authorized to transport cryogenic liquefied gases in a future\nrulemaking.\nPlease note a valve or valve fitting made of aluminum with internal rubbing or\nabrading aluminum parts that may come in contact with cryogenic liquefied oxygen\nmay not be installed on a cylinder used to transport cryogenic liquefied oxygen\nunless the parts are anodized in conformance with ASTM Standard B 580 (see\n§ 173.316(a)(4». Also, the DOT 4L's carriage by highway is subject to the\nconditions specified in § 177.840(a) of the HMR (see § 173.316(c)(3)(iii». Section\n177.840(a)(1) requires cylinders transporting Class 2 (compressed gas) materials to\nbe securely restrained in an upright or horizontal position, loaded in racks, or\npacked in boxes or crates to prevent the cylinders from being shifted, overturned, or\nejected from the motor vehicle under normal transportation conditions.\n02. You ask if, under §§ 173.316(c) and 178.57, the cylinder may have relief valves\ndesigned to operate at 22, 100, and 110 pounds per square inch (psi).\nA2. Under the HMR, pressure control systems for cylinders in cryogenic liquid service\nmust be designed and installed in a manner that complies with the requirements\nprescribed in § 173.301(f) and prevents the cylinder from becoming liquid full.\nThis means the pressure relief devices within these systems must be suitable for the\nintended service in that they are the correct size, type, quantity, pressure, in the\ncorrect location, and tested for the cylinder and material transported in\nconformance with Compressed Gas Association (CGA) pamphlets CGA S-1.1\n(pressure relief valves), except CGA Section 9.1.1.1 and CGA C-7 (labeling).\nPHMSA incorporates these pamphlets by reference under § 171.7(a)(3). CGA S1.1\nstates the set pressure of the pressure relief device must not be less than 75\npercent or more than 100 percent of the minimum required test p.ressure of the\ncylinder on which the llIe:::,<,:i,\\lIe '\\la\\'\\le i.s i.nsta\\led (see eGA SectlOn 4.3.2). In\n2\n\n<<<PAGE 3>>>\n\naddition, CGA S-1.1 states the pressure control valve for a DOT 4L cylinder must\n\"have a set pressure not to exceed 1-1/4 times the marked service pressure of the\ncylinder less 15 psi if vacuum insulation is used\" (see CGA Section 5.8.3). You\nstate the marked service pressure for your DOT 4L cylinder is 115 psi and it does\nhave vacuum insulation. Based on the information you provided, it is the opinion\nof this Office that the cylinder you described may be equipped with pressure relief\nvalves designed to operate at 128.75 psi. For the pressure relief valve to be\ndesigned to operate at 22, 100, and 110 psi, the marked service pressure of the\ncylinder must be 5.6,68, and 76 psi, respectively.\n03. You ask if, under §§ 173.316(c) and 178.57, the cylinder may be loaded and\nunloaded while mounted to a vehicle.\nA3. The answer is no. In accordance with § 177.834(h), discharge of the contents of\nany container subject to the HMR, other than a cargo tank or 1M portable tank,\nmust not be made before the container is removed from the motor vehicle.\n04. You also ask if the design you propose must be approved under a special permit\nissued by PHMSA.\nA4. The answer is yes. See Answer AI.\nI hope this satisfies your request.\nSincerely,\nT. Glenn Foster\nChief, Regulatory Review and Reinvention Branch\nStandards and Rulemaking Division\n3\n\n<<<PAGE 4>>>\n\nDrakeford, Carol\n• From: INFOCNTR (PHMSA) Ji1de\"'5\nSent: Tuesday, June 29,20101:17 PM J11\nTo: Drakeford, Carolyn (PHMSA) - 0 I \"7\nSubject: FW: Request for formal written interpretation of horizontal DOT 4L cryogenic liquid cylinders\nCarolyn,\nThanks,\nRob\nYet another request for a formal interpretation of the regulations.\nFrom: Keith Hall [mailto:khall@cvatanks.com]\nSent: Tuesday, June 29, 2010 12:34 PM\nTo: INFOCNTR (PHMSA)\nSubject: Request for formal written interpretation of horizontal DOT 4L cryogenic liquid cylinders\nThe purpose of this communication is to request formal written interpretation as to the fabrication of horizontal, versus\nvertical, DOT 4L cryogenic liquid cylinders per Part 178.57, subpart c, Specification 4L welded insulated cylinders.\neVA is a registered DOT facility, #CT-8039. CVA has the opportunity to quote on fabricating a specific type of a DOT 4L\ncylinder. These cylinders will comply in all aspect to Part 178.57, except they will be transported and used in the\nhorizontal position (the piping remains on the head of the cylinder, which will be one end of the vessel in the horizontal\nposition). Such cryogenic liquid cylinders were previously manufactured by Taylor-Wharton (Theodore, AL). We do not\nknow if they had an exemption/special permit to fabricate them - or if we are required to seek such.\nThese vessels are transported in a van for home medical oxygen delivery. They are designed with a relief valves to\noperate at 22 pSi, 100 psi, or 110 psi.\nThe only reference to cylinder orientation that we found in 178-57 - (p) (4) states: \"Special orientation instructions\nmust be marked on the cylinder (for example, THIS END UP), ifthe cylinder is used in an orientation other\nthan vertical with openings at the top ofthe cylinder.\"\nThis would lead us to believe that we can manufacture horizontal cylinders, but would need to mark which side is up. As\npreviously explained, the openings would still be on the head, just like other DOT 4L cylinders, but as they would be in\nthe horizontal position the openings would be on the end;\"with openings on the top of the cylinder\" is ambiguous in\nthis application.\nIn a related section, 173.316 (c), states: Specification cylinder requirements and filling limits. Specification\nDOT-4L cylinders (§ 178.57 of this sub-chapter) are authorized for the transportation of cryogenic liquids when\ncarried in the vertical position as follows:\"\nFilling in the horizontal position is not addressed. Is a special permit/exemption required to fill these horizontal liquid\ncylinders? Would a special permit/exemption be required if we wanted to fill these horizontal vessels while in the van,\nversus unloading them for filling every time, as it would be difficult to fill by weight? Would this be possible were we to\ndemonstrate that they are always filled under the DOT fill limit via a full trycock set for liquid statu rated at the MAWP of\nthe vessel, and or by a liquid level gauge?\nI appreciate your timely interpretation of these questions, and thank you for your assistance.\nSincerely,\n1\n\n<<<PAGE 5>>>\n\nI. Keith Hall\nEngineering Manager\neVA Inc.\n9528 Warren Road\nP.O. Box 1230\nMont Belvieu, TX 77580\nMain: 281-385-1204\nDirect: 281-576-4150\nCell: 832-386-5717\n-------\n-------\nEmail scanned by PC Tools - No viruses or spyware found.\n(Email Guard: 7.0.0.18, Virus/Spyware Database: 6.15310)\nhttp://www.pctoois.com\n-------\n-------\n2","truncated":false,"body_characters":10281}