{"operation":"document","citation":"17-0035","title":"Mr. Jared Sherman — Hazardous Materials Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"2017-12-28","effective_on":null,"summary":"17-0035 concerning 173.302a, 173.302b, 178.35, 180.215.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-17-0035.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-17-0035.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-17-0035","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/standards-rulemaking/hazmat/interpretations/56816/170035.pdf","body":"<<<PAGE 1>>>\n\nReference No. 17-0035\nDear Mr. Sherman:\nThis letter is in response to your April 6, 2017, e-mail requesting clarification of the Hazardous\nMaterials Regulations (HMR; 49 CFR Parts 171-180) applicable to the requalification of\ncylinders. Specifically, you ask about filling a Department of Transportation (DOT) cylinder in\nexcess of 10 percent in accordance with § 173.302a(b). You provide an example of a DOT 3AA\ncylinder that was marked with a service pressure of 3,000 psi and a plus (+) at the time of\nmanufacturing.\nWe have paraphrased and answered your questions as follows:\nQ1.\nYou ask for confirmation of your understanding that a cylinder with a service pressure of\n3,000 psi is allowed to use a service pressure of 3,300 psi, provided the cylinder passes\nhydrostatic inspection at the 3,300-psi rating.\nAl. Your understanding is incorrect. A DOT 3AA cylinder may be filled with a Division 2.2\nnon-flammable, non-liquefied gas to 10 percent in excess of its marked service pressure if\nall requirements contained in § 173.302a(b)(1) through (5) are met. The plus sign (+) is\nmarked on a cylinder to indicate compliance with the testing and evaluation requirements\nin § 173.302a(b)(2) through (4).\nFor requalification of a cylinder previously marked with a plus sign, the hydrostatic retest\nmust be performed using the water jacket method to determine the cylinder's elastic\nexpansion (see § 173.302a(b)(2)). The cylinder requalifier must know the elastic\nexpansion rejection (REE) value to ensure the cylinder's average wall stress or the\nmaximum wall stress does not exceed the wall stress limitation specified in\n§ 173.302a(b)(3).\nQ2.\nYou ask whether any hydrostatic test shop can apply the plus (+) rating, or if the rating\nmust be applied by the manufacturer.\nA2. The initial plus sign marking is typically applied by the manufacturer. A cylinder\nrequalifier may apply subsequent plus sign (+) markings. Both the manufacturer and\nrequalifier must ensure the conditions of § 173.302a(b)(2) through (4) are met in order to\nmark the plus sign. Only a plus sign (+) marked after the last (most recent) test or retest\n\n<<<PAGE 2>>>\n\nA3. DOT neither collects nor maintains REE values or other information from the\nmanufacturer's design for DOT specification cylinders. Manufacturers of DOT cylinders\ncomply with the recordkeeping requirements specified in § 178.35. Requalifiers of DOT\ncylinders comply with the recordkeeping requirements specified in § 180.215.\nQ4.\nYou ask whether the test facility or owner may stamp the REE value on a cylinder using\nthe test log data obtained by following the Compressed Gas Association (CGA) Pamphlet\nC-5 to determine allowance to fill a cylinder to 10 percent in excess of its marked service\npressure.\nA4. Only the manufacturer is authorized to apply the REE marking on a cylinder. If the\nmanufacturer did not mark the REE number, then the requalifier must either use the\ntabulated data or compute the limit using CGA Pamphlet C-5. See the final rule titled,\n\"Hazardous Materials: Requirements for Maintenance, Requalification, Repair and Use\nof DOT Specification Cylinders (HM-220D),\" published August 8, 2002 for additional\ninformation [67 FR 51633].\nQ5.\nYou ask if—in the event one or more cylinders are tested and a REE number(s) is\nrecorded in the test shop(s) logs—the DOT will accept a record of three such tests as\nbeing substantially correct for that specific cylinder model, and allow that number to be\nused for any other cylinder from the same production group. You specify by asking, \"If\nmy cylinder is tested and a REE number is found, can that be recorded or registered with\nthe DOT or other organization, for future use by owners of other 'same' cylinders?\"\nA5.\nIt is the opinion of this Office that a REE value determined at the time of manufacture for\na DOT 3AA cylinder would only be valid for other DOT 3AA cylinders of the same\ncylinder model that were also manufactured from the same \"lot.\"\nDOT permits computing the REE value in accordance with CGA Pamphlet C-5. Under\nCGA Pamphlet C-5 section 3.3.1, the \"k factor\" may be determined through procedures\nfollowed for \"three (3) cylinders typical of the design.\" This \"k factor\" can be used in\ncalculations related to the REE value. CGA Pamphlet C-5 also provides procedures for\nother calculations that require information from the manufacturer to determine the\n\"k factor\" or REE value. DOT also permits reference to data tabulated in CGA Pamphlet\nC-5, which was determined by CGA through an analysis of manufacturer data. Neither\nthe computations or data tabulations in CGA Pamphlet C-5 include a registry for cylinder\nrequalifiers.\n\n<<<PAGE 3>>>\n\n§ 173.302a(b)(5) of this subchapter, the test sheet must indicate the method by which any\naverage or maximum wall stress was computed.\" Test records are not prohibited from\nincluding additional information. Additional information about the source of the REE\nvalue may be helpful to a requalifier determining compliance with § 173.302a(b)(2)\nthrough (4).\nI hope this information is helpful. Please contact us if we can be of further assistance.\nSincerely,\nTAlenn Fast\nT. Glenn Foster\nChief, Regulatory Review and Reinvention\nStandards and Rulemaking Division\n\n<<<PAGE 4>>>\n\nHi Shante/Alice,\nPlease submit this as a letter of interpretation. I spoke with Mr. Sherman on some of these questions.\nPlease let me know if you have any questions.\nThanks,\nJordan\nFrom: Jared Sherman [mailto:the.jared.sherman@gmail.com]\nSent: Wednesday, April 05, 2017 4:53 PM\nTo: INFOCNTR (PHMSA) <INFOCNTR.INFOCNTR@dot.gov>\nSubject: Clarification of SCUBA tank hydrostatic test pressure regulations for recertification\nSir or Ma'am:\nI am trying to clarify DOT policy and regulations in regard to hydrostatic pressure testing and\ncertification of SCUBA tanks. The tank in question is a steel \"96.2\" that was produced by Pressed Steel\n(PST) in 1982.\nThe information stamped on the tank at manufacture reads:\nDOT 3AA 3000\n44307Y\n7 [PST] 82+\nAnd as I understand it, that means the tank received DOT certification as a 3AA (steel) tank for service\nat 3000 pounds, with service at 3300psi being allowed as long as the tank can pass a hydrostatic\ninspection at the \"plus\" pressure rating of 3300 pounds.\nFrom published statements by the DOT, I am told that any hydrostatic test shop can test the tank at\n3300psi and give a \"+\" rating if the tank complies with standards for elastic expansion, compared to\nwhat is called a \"REE\" rating for the tank.\nThis is the \"Rejection Elastic Expansion\" (REE) or how much the manufacture specifies the cylinder\nshould expand before it is considered unsafe.\nNormally a REE rating would be determined, according to DOT publications, by a procedure published\nin the CGA-5 manual, which most hydrostatic test shops are unable to perform either because they\nlack the equipment or do not understand the procedure. And the SCUBA industry, and the hydro shops\nthey use, almost all claim that this \"+\" rating cannot be given except upon manufacture, which\naccording to the DOT publications is materially incorrect. (We might call it a lie.)\n\n<<<PAGE 5>>>\n\n3- If one or more tanks are tested, and a REE number(s) recorded in the test shop(s) logs, is it true\nthat the DOT will accept a record of three such tests as being substantially correct for that\nspecific tank model, and allow that number to be used for any other tank from the same\nproduction group? i.e. If my tank is tested and a REE number found, can that be recorded or\nregistered with the DOT or other organization, for future use by owners of other \"same\" tanks?\n4- Is there any provision to allow the REE number, once determined for one tank, to be recorded\nfor future use for that tank, if it has not been stamped on the tank? (i.e. can the hydrostatic shop\nthat obtained the number document it in their test log, and then supply a copy of the log page,\nincluding the tank serial number, which can be used during future retesting, so the expensive\nand uncommon test procedure only has to be performed once, and the results used again in the\nfuture?\nI ask you these questions because the two industries (SCUBA and hydrostatic test) both consistently\nlie about whether recertification can be done to the + pressure rating, and their action forces divers to\nspend considerable money replacing perfectly good equipment, if the divers wish to maintain that 10%\nextra amount of air in the tanks. This is a safety issue. The industry effectively is stealing the safety\nmargin (10%) from divers by falsely claiming they cannot perform a simple hydro test to the DOT/CGA\nstandards for a + rating.\nConsidering that the typical 3000psi rated tank is normally tested to 5000psi, and that the typical\nindividual diver will in their entire lifetime use the tank for less than 10% of the rated 5000 psi duty\ncycle of the tank, there should be little concern about having the tanks properly tested and recertified\nto the 3300psi \"+ rating. It is well within the tested limits of the tank, and it gives the divers a\nsignificant safety margin in use.\nI would greatly appreciate your research into this somewhat arcane issue, and your formal reply on\npoint to the questions about determining, recording, and re-using REE numbers once they have been\nobtained.\nJared Sherman\nYou are requested to please withhold my personal information (address and phone) from any public\nrecords access, it is supplied for correspondence purposes only.\n2","truncated":false,"body_characters":9457}