Linde Gas North America LLC — Hazardous Materials Safety Interpretation

Page 1U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration 1200 New Jersey Ave, S.E. Washington, D.C. 20590 JUL 0 1 2013 Mr. Guy Dalton Head of Transport Compliance/Safety Linde Gas North America LLC 13 0 Briar Hill Painesville, OH 44077 Ref. No.: 13-0092 Dear Mr. Dalton This is in response to your April 23, 2013 letter requesting clarification of the requirements for filling DOT 3A and 3AA specification cylinders under the Hazardous Materials Regulations (HMR; 49 CPR Parts 171-180). Specifically you asked if "Deuterium, compressed, UN1957" may be considered as the same as "Hydrogen, compressed, UN1 049" for the purposes of determining the requalification period in accordance with § 180.209 or the eligibility to fill cylinders to 110% of the marked service pressure. DOT 3A or 3AA cylinders with a water capacity of 56.7 kg (125 lbs) or less used exclusively for the gas service specified in§ 180.209(b)(l) may be requalified every ten years instead of every five years provided certain requirements are met. While § 180.209(b )(1) specifies hydrogen as a permitted gas service, deuterium is not specified. Therefore cylinders used for deuterium must be requalified every five years. In your letter, you stated that your company is a party to Special Permit 6530, which allows the filling of3A, 3AA, 3AX and 3AAX cylinders with hydrogen and mixtures ofhydrogen with helium or nitrogen to 110 % of the cylinder's marked service pressure. The special permit authorizes the transport of hydrogen and mixtures of hydrogen. Deuterium and mixtures of deuterium are not authorized by the special permit. I hope this information is helpful. If you have further questions, please do not hesitate to contact this office. Senior Regulatory Advisor Standards and Rulemaking Division#

Page 2April23, 2013 130 Briar Hill Painesville, Ohio 44077 440-354-5614 440-579-0203 guy .dalton@linde.com Office of Hazardous Materials Standards Pipeline and Hazardous Materials Safety Administration, Attn: PHH-1 0 U.S. Department of Transportation, East Building 1200 New Jersey Avenue, SE. Washington, DC 20590-0001. Request for Interpretation Dear Sir or Madame, Linde Gas North America LLC (Linde) is requesting interpretation and guidance regarding the use DOT 3A and 3AA for the transport of Deuterium. Background Deuterium is an isotope of Hydrogen and is filled into 3A and 3AA cylinders with less than 125lb water capacity as permitted by 49CFR173 .301 49CFR180.209(b)(l) permits the requalification of such cylinders for a period often years ifthe requirements of 180.209(b )(1 )(ii) are met. This subparagraph allows the filling of hydrogen into such cylinders tested at ten year intervals. DOT-SP6530, to which Linde Gas North America LLC holds party status allows filling of3A, 3AA, and 3AAX cylinders to 11 0% of the cylinder's rated service pressure and excepts the need to comply with 173 .302a(b) if all provisions of the Special Permit are met.. Question 1 Is Deuterium, an isotope of Hydrogen, to be considered as hydrogen for purposes of determining allowed retest intervals of 3A and 3AA cylinders as authorized in 180.209(b )(1 )(ii). Question 2 For filling of3A, 3AA and 3AAX cylinders at pressures of 110% of the cylinder rated service pressure as allowed by DOT-SP5630, is Deuterium to be considered as Hydrogen. Can deuterium be filled to 110% of rated service pressure into the mentioned cylinders? Linde Gas North America LLC#

Page 3A written response at your earliest convenience is appreciated. Sincerely Guy Dalton Head of Transport Compliance/Safety Linde Gas North America LLC 440-251-0303 guy.dalton@linde.com Linde Gas North America LLC#