{"operation":"document","citation":"05-0081","title":"Chemical Accident Reconstruction Service, Inc. — Hazardous Materials Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"2005-07-28","effective_on":null,"summary":"05-0081 response to Chemical Accident Reconstruction Service, Inc. concerning 173.306, 178.33a.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-05-0081.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-05-0081.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-05-0081","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/2005/050081.pdf","body":"<<<PAGE 1>>>\n\nJUL 2 8 2005\nS. Departmel\nTransportatic\n400 Seventh Street, S.W.\nWashington, D.C. 20590\npeline an\nAdministration\nazardous Materials Safel\nMr. Michael Fox\nRef. No. 05-0081\nChemical Accident Reconstruction Service, Inc.\nTucson, Arizona 85749\n9121 E. Tanque Verde Road #105\nDear Mr. Fox:\nThis responds to your March 30, 2005 letter requesting clarification of the Hazardous Materials\nRegulations (HMR; 49 CFR Parts 171-180) applicable to DOT 2Q inner non-refillable metal\nreceptacles. Specifically, you ask if a DOT 2Q container that passes a hydraulic pressure test\nand fails when subjected to a heat-to-burst test would satisfy the pressure test requirements for\nDOT 2Q containers specified in § 178.33a-8.\nAs specified in § 178.33a-8, one out of each lot of 25,000 DOT 2Q containers or fewer,\nsuccessfully produced each day must be pressure tested to destruction and must not burst below\n270 psig. The HMR do not specify the type of pressure test that must be used, nor do the HMR\nrequire multiple pressure tests to be conducted on a single lot of DOT 2Q containers. The\nmanufacturer is responsible for selecting the appropriate pressure test method to use on the\nsingle container selected from each lot. Therefore, if a manufacturer chooses to use a hydraulic\npressure test method and the container does not burst below 270 psig, the lot of DOT 2Q\ncontainers passes the pressure test requirement. However, if a manufacturer chooses to use a\nheat-to-burst test method and the container bursts below 270 psig, the lot of DOT 2Q containers\nfails the pressure test requirement and must be rejected. In that event, 10 additional containers\nmay be selected at random from the same lot and subjected to the test under which the failure\noccurred. If any of the 10 additional containers fails the test, the lot of DOT 2Q containers\nmust be rejected.\nIf you would like to propose a change to the HMR, you may submit a petition for rulemaking\nfollowing procedures outlined in § 106.95.\nI hope this information is helpful. Please contact us if we can be of further assistance.\npress\nOffice of Hazardous Materials Standards\n193.306 (a)(3) ii\n178.330-8\n050081\n\n<<<PAGE 2>>>\n\nChemical Accident Reconstruction Services, Inc.\nMarch 30,2085\nWebb\nAugust 28, 2004\nJohn A. Gale\nChief, Standards Development\nOffice of Hazardous Materials Standards\nU.S. Department of Transportation\nCompressed Gases\nWashington, D.C 20590\n05-0081\nRe: 49 CFR 173.306(a)(3)(ii)\nDear Mr. Gale:\nThank you for your letter (copy attached) of March 18, 2005 in answer to my inquiry of\nAugust 28, 2004.\nAfter waiting such a long time (about 7 months), it was disappointing that your letter did\nnot answer the question that was asked. Your letter was also inconsistent with my\nconversations with Mr. Staniszewski. Therefore, I will re-ask the question and try to\nmake it clearer.\nFor the purpose of my question, please assume I am asking only about DOT 2Q\ncontainers. The question has to do with test method to determine burst pressure and the\nfinding that the results depend on the test method used to perform the burst test.\nIf I perform a burst test using hydraulic (water) methods, the containers do not burst\n270 psig, but the double seam does not unravel or leak until higher pressures (over 350\nbelow the DOT minimum burst pressure of 270 psig. They may begin to deform below\npsig) are reached. Therefore, via the hydraulic test, the containers pass the DOT 270 psig\nburst criterion. As I discussed with Mr. Staniszewski, the hydraulic method is very slow\nand does not involve any kinetic energy.\nOn the other hand, if I perform heat-to-burst tests, the containers explode (violently) at\npressures substantially below the 270-psig minimum. I have seen explosions of DOT 20\ncontainers as low as 180-200 psig. These are the same DOT 2Q containers that pass the\nhydraulic test with flying colors. The different result is due to the kinetic energy present\nin the heat-to-burst test that is not present in the hydraulic testing.\nWhile I am not making an argument one way or the other, it is obvious that transporters\nand consumers rarely encounter DOT 2Q containers filled with high-pressure water. On\nthe other hand, there is a definite possibility that they might encounter a DOT 2Q\ncontainer filled with its contents, which have been exposed to some type of heat.\n9121 E. Tanque Verde Road #105, Tucson, Arizona 85749\n800-MIKE-FOX (645-3369)\nFax: 520-749-0861\n\n<<<PAGE 3>>>\n\nFrom the viewpoint transporter and consumer safety, it would seem that if a DOT 2Q\ncontainer violently explodes at pressures well below 270-psig in a heat-to-burst test, then\nst. It seemed that Mr. Staniszewski agreed with that when we spok\nnat container would NOT meet DOT specifications, even if it passed a hydraulic burs\nTherefore, the question I would like to have answered is:\nIf a DOT 2Q container passes the 270-psig burst requirement via a\nhydraulic pressure test, but explodes well below 270-psig in a heat-to-burst\ntest, does that container pass or fail DOT 2Q burst specifications?\nYour prompt answer to the above simple question will be greatly appreciated.\nThank you for your assistance\nSincerely,\nMICHAEL FOX\nMichael Fox, Ph.D.\nFounder\nP.S. Note that the experiments demonstrating the differences between hydraulic test\nmethods and heat-to-burst testing have been accepted for June publication in a peer-\nreviewed journal. They will also be presented, discussed and published in more detail at\nthe Fall ASM Conference.\nPage 2 of 2","truncated":false,"body_characters":5491}