{"operation":"document","citation":"12-0030","title":"U.S. Department of Defense, Attn: AMSSD-SA — Hazardous Materials Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"2012-05-22","effective_on":null,"summary":"12-0030 response to U.S. Department of Defense, Attn: AMSSD-SA concerning 171.1, 172.101.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-12-0030.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-12-0030.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-12-0030","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretations/2012/120030.pdf","body":"<<<PAGE 1>>>\n\nU.S. Department\nof Transportation\nPipeline and Hazardous\nMaterials Safety\nAdministration\nMAY 2 2 2012\n1200 New Jersey Avenue, SE\nWashington, D.C. 20590\nMr. Elias V. Cantu\nSafety Manager, Military Surface Deployment and Distribution Command\nU.S. Department of Defense, Attn: AMSSD-SA\nOne Soldier Way,\nScott AFB, IL 62225\nRef. No. 12-0030\nDear Mr. Cantu:\nThis responds to your January 24, 2012 letter regarding the applicability of the Hazardous\nMaterials Regulations (HMR; 49 CFR Parts 171-180) to a device that contains a compressed\ngas. According to your letter, a Raman cell (\"the cell\") contains methane gas pressurized at\nI ,000 to I ,200 psig and has a volume of 2. 7 cm3\n. The cell was proof tested to a safety factor of\n2 times the maximum operating pressure (MOP) (i.e., 2,400 psig) without structural failure and\na structural analysis shows a safety factor greater than 4 times the MOP (i.e., 4,800 psig). The\ncell is contained in a sealed laser unit lens and located near the housing for a resonator. By your\ncalculations, if a structural failure allowing a leak from the cell were to occur in the lens housing\nor were to leak into the resonator housing, the percentage concentrations for methane are\nestimated at 0.8% and 47%, respectively, which are outside the bounds of the explosive limits\nfor methane gas (i.e., 5% to 15%). You indicate that although highly unlikely, a partial leak in a\nconcentration within the explosive limits could occur. In a telephone conversation with a\nmember of my staff, you indicated that ignition of this minute amount of methane gas would be\nequivalent to the energy released from striking a match. Specifically, you ask for clarification\nwhether the cell containing the compressed methane gas is subject to the HMR.\nPHMSA regulates the transportation in commerce of materials it determines are hazardous in\nthat \"the amount and form [of the material] may pose an unreasonable risk to health and safety\nor property.\" 49 U.S.C. 5103, as delegated to PHMSA in 49 CFR 1.53(b). Based on the\ninformation provided in your letter and subsequent telephone conversation, the Raman cell is\nnot shipped in a quantity and form that poses an unreasonable risk to health and safety or\nproperty during transportation and, therefore, is not subject to regulation under the HMR.\nI hope this information is helpful. If you have further questions, please contact this office.\n~>~\nActing Chief, Standards Development Branch\nStandards and Rulemaking Division\n\n<<<PAGE 2>>>\n\nDer ki()cfere n\nDEPARTMENT OF THE ARMY I D I\nMILITARY SURFACE DEPLOYMENT AND DISTRIBUTION COMMAND scon AFB, ll 62225-5006 9 17 2- ·\n1 SOLDIER WAY A I~ .,t\nr•p p J I(! lUOI '!J\n/2 .. 0()30\nDirectorate of Safety (AMSSD-SA)\nJanuary 24, 2012\nStandards and Rulemaking Division\nPipeline and Hazardous Materials Safety Administration\nAttn: PHH-10\nU.S. Department of Transportation\nEast Building\n1200 New Jersey Avenue, SE\nWashington, DC 20590-0001\nIn accordance with the provisions of Title 49, Code ofFederal Regulations (CFR), Part 105, Section\n105.20, the Department of Defense (DOD) hereby requests an Interpretation of the Hazardous Materials\nRegulations as outlined below. DOD petitions for a clarification of whether the HMR applies to the\ntransportation of a small quantity of methane gas contained in Ramen cells. The following file number is\nassigned:\nFile Number: 03-12 (0124)\nRe: Request for Interpretation- Ramen Cells\nProponent:\nU.S. Department of Defense\nSurface Deployment and Distribution Command\nOne Soldier Way\nScott AFB, n., 62225-5006\nElias Cantu\nPH: ( 618) 220-5041\nFAX: (618) 220-7821\nEMAIL: elias.v.cantu.civ@mail.mil\nThe DOD has a need to ship weapons systems with Ramen Cell lenses which contain a minute trace of\nmethane gas within a sealed laser unit lens. Please see attached Ramen Cell and Resonator Cavity\ndimensions (Att 1). Due to the safety performance testing conducted and the structural analysis of the\nouter packaging, we do not believe that it poses an unreasonable risk to health, safety or property when\nshipped in commerce and therefore should not be considered a hazardous material.\nRationale:\nThe Ramen Cell contains methane gas pressurized at 1000 to1200 psig. The gas cell volume is 2.7 cubic\ncentimeters with a stored energy of less than 30 ft-lbs. A structural ahalysis ofthe Raman Cell was\nperformed and results show a safety factor of greater than four times the maximum operating pressure of\n4800 psig. The cell was also proof tested to a safety factor of greater than two times the maximum\noperating pressure of 2400 psig without any structural failure.\nThe conditions required for methane gas to ignite when mixed with normal air require a methane\nconcentration level ofbetween 5% (lower explosive limit (LEL)) and 15% (upper explosive limit\n(UEL)). The resonator is located in a 245.8 cubic centimeter dry nitrogen purged housing. If structural\nfailure of the entire Raman Cell permitted leakage into this cavity, it is calculated that the concentration of\nmethane would be greater than 47%, which is above the UELand would not support ignition. In the\nPrinted on • Recycled Paper\n\n<<<PAGE 3>>>\n\n-2-\nunlikely event a partial leak results in a 15% methane mixture in the housing, the energy released would\nbe less than 1.4 BTU's. The lens housing structure is strong enough to contain the entire leak. In\naddition, the interior free space of the housing is greater than 28,000 cm3, and it has been calculated that a\ntotal cell leakage would result in a methane concentration of less that 0.8% which is below the LEL and\nwould not support ignition.\nThe attached DOT Letter oflnterpretation (Att 2) Ref. No. 09-0037 was issued for a similar\nsituation - a very small amount of flammable gas contained in a glass tube which is inside of a\nlarger container. If the flammable gas were released into the larger container the flammable gas\nconcentration is well below the Lower Explosive Limit of the flammable gas. Our situation has the added\nsafety margin in that the concentration of flammable gas in the glass tube is above the flammable range\nand therefore could not ignite in either the glass container or the metal housing. ·\nTo date, the Department of Army has transported well over 2,800 Ramen Cells in varying weapons\nsystems using Military Air with no reported incidents.\nThis request is submitted by Mr. Elias V. Cantu, (618) 220-5041, e-mail elias.v.cantu.civCW,mail.mil or\nusarmy.scott.sddc.mbx.omb-for-safety@mail.mil Safety Manager, Military Surface Deployment and\nDistribution Command, ATTN: AMSSD-SA, One Soldier Way, and Scott AFB, IL 62225.\nSincerely,\n0~t. 1/V(.J_\nDaniel A. Maham\nDirector of Safety","truncated":false,"body_characters":6670}