{"operation":"document","citation":"09-0265","title":"Air Liquide America Specialty Gases LLC — Hazardous Materials Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"2010-01-27","effective_on":null,"summary":"09-0265 response to Air Liquide America Specialty Gases LLC concerning 173.302a.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-09-0265.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-09-0265.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-09-0265","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretations/2009/090265.pdf","body":"<<<PAGE 1>>>\n\nU.S. Department 1200 New Jersey Ave., SE\nof Transportation Washington, DC 20590\nPipeline and Hazardous Materials\nSafety Administration\nJAN 2 7 2010\nMr. Ralph Diaz\nAir Liquide America\nSpecialty Gases LLC\n2700 Post Oak Blvd.\nHouston, TX 77056\nRef. No. 09-0265\nDear Mr. Diaz:\nThis responds to your e-mail regarding the reuse of a cylinder under the Hazardous Materials\nRegulations (HMR; 49 CFR Parts 171-180). Specifically, you ask under what condition the\nHMR authorize a cylinder previously used in carbon monoxide (CO) service to be refilled\nwith a high-purity gas such as helium, argon, or hydrogen. Additionally, you ask whether the\nHMR define the term \"dry,\" as used in § I 73.302a(c).\nWhen promulgating regulations regarding the filling and transportation of cylinders used\nexclusively in CO service, we did not foresee the need to codify any condition or minimum\nqualification for the continued use of such cylinders in another gas service. Although the\nHMR do not prohibit such practice, PHMSA strongly discourages it for safety reasons. For\nexample, the moisture in CO may cause internal micro-cracking of the cylinder. Such\ncracking may not be detected through internal visual inspection or hydrostatic testing.\nTherefore, until a regulatory solution is adopted, we recommend the following tests be\nperformed, at a minimum, if considering a change in gas service:\n1. Proof pressure test equal to test pressure of the cylinder with a minimum of one (1)\nminute hold time; and\n2. 100% side wall ultrasonic examination (UE) using shear wave with accept/reject\ncriteria of 5% of design minimum wall thickness.\nTen percent overfill of the cylinders is not recommended. The term \"dry,\" as used in\n§ 173.302a( c), is not defined in the HMR. For the purposes of § 173.302a( c), \"dry\" means a\n\n<<<PAGE 2>>>\n\ngas having a dew point at or below -46.7 °C (-52 OF) at 101.3 kPa (14.7 psia) (one\natmosphere).\nThank you for bringing this matter to our attention. If we can be of further assistance, please\ncontact this office.\nSincerely,\n.~\nHattie L. Mitchell\nChief, Regulatory Review and Reinvention\nOffice of Hazardous Materials Standards\n2\n\n<<<PAGE 3>>>\n\nPage 1 of 1\nDrakeford, Carolyn (PHMSA)\nFrom: Mitchell, Hartie (PHMSA) 'S+e\\let1S\nSent: Thursday, November 12, 200911:58 AM\nTo: Drakeford, Carolyn (PHMSA)\n~ 113 ·302a.. (ej\nSubject: FW: 49CFR173.302a(c) ~ 11'r1c1ers\nFrom: Diaz, Ralph [mailto:Ralph,Diaz@Airliquide,com] ~q-OLloS\nsent: Thursday, November 12, 2009 11:01 AM\nTo: Toughiry, Mark (PHMSA); Mitchell, Hattie (PHMSA); Cassidy, Duane (PHMSA); Chaney, Wayne (PHMSA)\nSubject: 49CFR173,302a{c)\nNot sure of proper DOT dept. to answer the following:\n49CFR173.302a{c} limits the pressure (to 5/6 service pressure) of cylinders filled with dry carbon monoxide and\nalso limits the pressure further (to only 1000 psi) of cylinders of 'wet' carbon monoxide.\nQuestions:\nWhat is DOT's intent on the disposition and continued use of these cylinders when LATER filled with other clean\nhigh purity gases like helium, argon, hydrogen, etc? Can the same cylinders be filled to full service pressure with\nthese 'clean gases', filled to 10% overfill, etc. provided hydrotest is acceptable for these filling operations? Was it\nthe intent of DOT to limit the filling pressure of all gases once exposed to carbon monoxide?\nDid DOT ever define 'dry'?\nRegards,\nRalph Diaz\n11112/2009","truncated":false,"body_characters":3377}