{"operation":"document","citation":"17-0074","title":"ESF Transport — Hazardous Materials Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"2018-08-14","effective_on":null,"summary":"17-0074 response to ESF Transport; Western International Gas & Cylinders, Inc. concerning 172.101, 173.306, 177.837.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-17-0074.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-17-0074.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-17-0074","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/standards-rulemaking/hazmat/interpretations/56846/170074.pdf","body":"<<>>\n\nWestern International Gas & Cylinders, Inc.\nP.O. Box 668\nBellville, TX 77418\nReference No. 17-0074\nDear Ms. McKenzie:\nThis letter is in response to your July 13, 2017, email requesting clarification of the Hazardous\nMaterials Regulations (HMR; 49 CFR Parts 171-180) applicable to the transport of \"Acetylene,\nsolvent free\" as a gas sample. Specifically, you request confirmation of your understanding that\n\"Acetylene, solvent free\" may be transported under the Hazardous Materials Table entry\n\"UN3167, Gas sample, non-pressurized, flammable, n.o.s. (Acetylene), Class 2.1\" in accordance\nwith the requirements of § 173.306(a)(4).\nIn your email, you provided data indicating that when prepared in accordance with\n§ 173.306(a)(4), \"Acetylene, solvent free\" would not meet the criteria for \"forbidden\" but rather\nonly exhibit the properties of a Division 2.1 flammable gas. Additionally, you provided data\nindicating that the pressure in the gas sample container is below that which is required to\ngenerate an explosion, and therefore the stability issue that would typically require acetylene to\nbe transported in solvent is not present.\nAs specified in § 172.101(d)(1), if any specifically listed forbidden material is diluted, stabilized,\nor incorporated in a device and is classed in accordance with the definitions of hazardous\nmaterials contained in Part 173 of the HMR, it is no longer considered a forbidden material.\nBased on the information you provided and the requirements of the HMR, it is the opinion of this\nOffice that the material \"Acetylene, solvent free\" in your scenario may be described as\n\"UN3167, Gas sample, non-pressurized, flammable, n.o.s. (Acetylene), Class 2.1, \" subject to the\nconditions prescribed in § 173.306(a)(4) as it would not be unstable at pressure of 15.22 psia or\nless.\nI hope this information is helpful. Please contact us if we can be of further assistance.\nSincerely,\nuan A. 12\nDuane A. Pfund\nInternational Standards Coordinator\nStandards and Rulemaking Division\n\n<<>>\n\nPlease log the attached request as a formal request for interp.\nThanks\nAaron\nFrom: Kathy McKenzie [mailto:kathymckenzie@westernintl.com]\nSent: Thursday, July 13, 2017 4:11 PM\nTo: Wiener, Aaron (PHMSA) ; Tarr, Richard (PHMSA) \nCc: Brian Schumann < brianschumann@westernintl.com>\nSubject: Letter Of Interpreation request\nMr. Wiener,\nPlease find a letter requesting an interpretation with back up documentation. We have a customer that is waiting for us\nto be able to do this testing. If you could send the response by email first it will be greatly appreciated.\nRespectfully submitted,\nKathy McKenzie, CDS\nSafety & Compliance Director\nWestern International Gas & Cylinders, Inc.\nP.O. Box 668/7173 Hwy 159E\nBellville, Tx 77418\nPhone: (979) 413-2125\nMobile: (979) 885-8143\nE-mail: kathymckenzie@westernintl.com\nwww.westernintl.com\n\n<<>>\n\nI had a discussion with the office of Standards yesterday (Aaron Wiener) to discuss your SP request to ship acetylene\n(solvent free) as a gas sample in compliance with the requirements in 173.306(a)(4).\nAt the end of the discussion it was decided that this issue would be best resolved with a letter of interpretation.\nI suggest you contact the Standard's office (Aaron) and initiate a formal request for a letter of interpretations.\nIt is important to make it clear in your request that the materials you need to ship \"Acetylene, solvent free\" would be\nshipped as \"Gas Sample, non-pressurized, Flammable N.O.S. (Acetylene) and that acetylene does not meet the criteria of\n\"forbidden\" at 15.22 PSIA, but only exhibits the properties of a flammable gas. Include the information you provided in\nyour SP application (DOT SP 20380), that shows that the material must exceed 20 PSIA before it can become unstable.\nYou can also cite that ICAO support that position.\nThanks,\nRichard Tarr, Ph.D.\nChemist/Transportation Specialist\nPipeline and Hazardous Material Safety Administration\nPHH-21 (Engineering and Research Division)\nRoom (E21-334)\n1200 New Jersey Avenue, SE\nWashington, DC 20590-0001\nPhone 202-366-4493 Fax 202-366-5713\nEmail richard.tarr@dot.gov\nFrom: Herzog, Kenneth (PHMSA)\nSent: Tuesday, July 11, 2017 11:46 AM\nTo: Kathy McKenzie \nCc: Tarr, Richard (PHMSA) \nSubject: Permits\nGood morning Kathy,\nThe tech engineer working on your permits stopped by and asked who to contact at Western about your applications. I\ntold him you were the person that we have dealt with. He asked that you give him a call when you have a chance.\nDr. Richard Tarr, 202-366-4493\n1\n\n<<>>\n\nAaron wiener\nStandards Office\nDepartment of Transportation\nPipeline and Hazardous Materials Safety Administration\n1200 New Jersey Avenue, SE\nEast Building, 2d Floor, PHH-30\nWashington, DC 20590\nRe: Letter of Interpretation Request\nDear Mr. Wiener\nWe are asking for an interpretation in making sure we can ship acetylene (solvent free) as\na gas sample in compliance with the requirements in 173.306 (a)(4).\nWe do not believe this will require a special permit and will ship as:\n\"Gas sample, non-pressurized, Flammable N.O.S. (Acetylene).\"\nOur understanding is that acetylene does not meet the criteria of \"forbidden\" at 15.22\nPSIA, but only exhibits the properties of a flammable gas.\nICAO does support our position as I was speaking to Mr. Richard Tarr yesterday\nconcerning this matter. I am attaching some back up documentation per Mr. Tarr's\nsuggestion.\nIf any further information is required please do not hesitate to contact me directly at (979)\n413-2125.\nRespectfully submitted,\nKathy\nMe Kingse\nKathy McKenzie\nSafety & Compliance Director\nEmail: kath mckenzie westernintl.com\n979-413-2125 office\n979-885-8143 cell\nP.O. Box 668, 7173 Hwy 159E Bellville, TX, 77418 77418-0668\nMain 979.413.2100\nFax 979.413.2204\nwww.westernintl.com\n\n<<>>\n\nUnlike most hydrocarbons the formation of acetylene is not thermodynamically favored compared to its component\nelements as can be seen in Table 1 where the heat of formation and free energy of formation are positive values unlike\nnormal butane where the heat of formation and free energy of formation are negative values. This unfavorable\nthermodynamic condition allows acetylene to decompose when given a sufficient trigger. The decomposition is\nexothermic and the release of energy during the initial decomposition can provide the trigger to decompose the\nadjacent acetylene, leading to a continuing decomposition until all of the acetylene in the container has decomposed.\nJones et al. (1944) determined the minimum acetylene pressure required to generate an explosion by igniting acetylene\nwith a platinum wire or a piece of hot carbide was 5.9 psig for dry acetylene at 25 C (77 F) and 7.2 psig for acetylene\nsaturated with water at 25 C. The requested special permit will limit the pressure in the container to less than 15.22\npsia (0.53 psig) per 49CFR173.306.\nMiller (1965, pg 476) states that at one atmosphere absolute or less, the decomposition of acetylene is not self-\nsustaining except under certain special conditions. These special conditions (pg 489-490) include the use of explosives\nto start the reaction, heating the container with a kerosene flame to 500C, or an exceptionally large ignition area (1.6 cm\nwidth) created with an explosive sample, a powerful spark or a red hot chrome-nickel coil. The special conditions\nnecessary to cause acetylene at one atmosphere to completely decompose are not going to be present during transport.\nThe pressure in the container is below the pressure required to generate an explosion and therefore the stability issue\nwith acetylene that would typically require it to be shipped in solvent is not present. Under these conditions acetylene\npresents no more hazard than any other flammable gas shipped under 49CFR173.306. The energy contained in the\nacetylene sample bag is less than the energy allowed in a single lighter. Therefore, the transportation of gas sample\nbags is no riskier than the transportation of lighters and should be allowed.\nJones, G.W., Scott, G.S., Kennedy, R.E., and Huff, W.J. (1944), Report of Investigations 3755, Explosion in Medium-\nPressure Acetylene Generators, US Bureau of Mines\nMiller, S.A., (1965), Acetylene: Its Properties, Manufacture and Uses, Volume 1, Ernest Benn, London\nPerry, R.H. and Chilton, C.H., (1973), Chemical engineers' handbook, McGraw-Hill, New York\nUS EPA, METHOD 18-MEASUREMENT OF GASEOUS ORGANIC COMPOUND EMISSIONS BY GAS CHROMATOGRAPHY,\nhttps://www3.epa.gov/ttnemc01/promgate/m-18.pdf retrieved 6/17/2016","truncated":false,"body_characters":8619}