{"operation":"document","citation":"05-0053","title":"Space Gateway Support, LLC — Hazardous Materials Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"2005-05-12","effective_on":null,"summary":"05-0053 response to Space Gateway Support, LLC concerning 171.1, 173.22.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-05-0053.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-05-0053.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-05-0053","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/2005/050053.pdf","body":"<<<PAGE 1>>>\n\nU.S. Department\nof Transportation\n400 Seventh Street, S.W.\nWashington, D.C. 20590\nPipeline and\nMAY 12 2005\nHazardous Materials Safety\nAdministration\nMr. William Deneuté\nRef No.: 05-0053\nP.O. Box 21237\nSpace Gateway Support, LLC\nKennedy Space Center, FL 32815\nDear Mr. Deneuté:\nThis responds to your February 23, 2005 letter requesting clarification of the weight\npercent threshold for classification of mixtures of nitric oxide and dinitrogen tetroxide\nunder the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180). You state\nthat a threshold of 11% nitric oxide in a mixture with dinitrogen tetroxide appears to be\nthe poin: where the characteristics of the mixture diverge from that of pure \"Dinitrogen\ntetroxide, UN1067.\" You request that 11% be the threshold level where a mixture of\nnitric oxide and dinitrogen tetroxide is classified as \"Nitric oxide and dinitrogen tetroxide\nmixtures, UN1975\" rather than \"Dinitrogen tetroxide, UN1067.\"\nIn accordance with § 173.22, it is the shipper's responsibility to determine the shipping\ndescription for the material being transported. When selecting a proper shipping name,\nthe shipper must select the name that most appropriately describes the material (see\n§ 173.101(c)(12)). For a mixture of nitric oxide and dinitrogen tetroxide that meets the\ndefinition of a Division 2.3 material that is poisonous by inhalation in Hazard Zone A and\nexhibits oxidizer and corrosive subsidiary hazards, it is the opinion of this Office that,\nnotwithstanding the percentage of nitric oxide in the mixture, the most appropriate\nshipping description is \"Nitric oxide and dinitrogen tetroxide mixtures, 2.3 (5.1, 8), UN\n1975.\" The proper shipping name \"Dinitrogen tetroxide\" may be used only for pure\ndinitrogen tetroxide that meets the definition of a Division 2.3 material that is poisonous\nby inhalation in Hazard Zone A and exhibits oxidizer and corrosive subsidiary hazards.\nI hope this information is helpful. Please contact us if you require additional assistance.\nSincerely,\n/\nChief, Standards Development\nOffice of Hazardous Materials Standards\n14/.1\n050053\n173.22\n\n<<<PAGE 2>>>\n\nSupko\n3171:1\n-\nSpace Gateway Support, LLC\nExemption\nKennedy Space Center, FL 32815-0237\nP.O. Box 21237\n05-0053\nDATE:\nFebruary 23, 2005\n230-05-036\nTO:\nEdward T. Mazullo. Director\nOffice of Hazardous Materials Standards\nUS DOT / RSPA (DHM-10)\n400 7\" Street SW.\nWashginton, D.C. 20590-0001\nSUBJECT:\nREQUEST FOR WRITTEN INTERPRETATION REGARDING THE WEIGHT\nPERCENT THRESHOLD FOR CLASSIFYING NITRIC OXIDE AND\nDINITROGEN TETROXIDE MIXTURES WITH THE UN1975 IDENTIFIER - 49\nCFR 172-101.\nDear Mr. Mazullo,\nCurrently, NASA - KSC transports MON-1 and MON-3 (Mixed Oxides of Nitrogen and\nDinitrogen Tetroxide) under exemptions DOT-E 10887 and 11383 (as grantee) under the UN ID\n1067 (DiNitrogen Tetroxide.) NASA is also a party to exemptions DOT-E 03121 and 11580 and\nwill forward this interpretation to the grantees (DOD and Columbiana Boilers.)\nOur concerr. is that the weight percent of NO is so low (1% and 3% respectively) that the\nmixtures ex nibit the same characteristics as the pure Dinitrogen Tetroxide. There are occasions\nwhere MON-10 is transported under some of the above exemptions also. This mixture does\nexhibit a higher vapor pressure so the UN 1975 designation may be prudent there but we believe\nthe vapor pressure really diverges above 11% NO by weight. If there is no set weight percent\nwhich the OHM has identified, we would like to submit 11% (MON-11) as a threshold level as\nthat is the point where the characteristics appear to diverge from NTO. We would concede that a\nconservative level would be 7% NO by weight which is the point where the vapor pressures\nshows a 50% increase above atmospheric pressure.\nCurrently there is a modification request in by NASA for adding UN 1975 to DOT-E 11383 as an\nadditional Division 2.3 material in non-DOT specification Steel cylinders (FR Vol. 70, No. 13,\n1/21/05 - 11383-M.) If the conservative weight percent of NO (7%) is accepted as a limit for\nUN 1975, we would respectfully request the modification be cancelled as MON-10 is not\ntransported under that exemption.\nSincerely,\nwallan C lenenti, 2/23/05\nWilliam Derieuté\nSpace Gateway Support, LLC\nAttachments\nVapor Pressure Calculations & interpolation chart\nCo:\nChuck Davis, TA-E3; Kyrn Craig, UPC-272\nDwayne Breaux, SGS-127; Hemant Solanky, SGS-127\n* Recycled paper","truncated":false,"body_characters":4415}