{"operation":"document","citation":"63 FR 58460","title":"Hazardous Materials: Requirements for DOT Specification Cylinders","source_type":"rulemaking","agency":"Research and Special Programs Administration","status":"proposed","official":true,"published_on":"1998-10-30","effective_on":null,"summary":"RSPA proposes to amend certain requirements in the Hazardous Materials Regulations (HMR) to establish four new DOT cylinder specifications and to revise the requirements for maintenance, requalification, and repair of all DOT specification cylinders. In addition, RSPA proposes to: revise the requirements for approval of cylinder requalifiers, independent inspection agencies, and nondomestic chemical analysis and tests; revise the cylinder requalification, maintenance and repair requirements; and to revise the requirements for hazardous materials that are authorized to be offered for transportation in cylinders. Finally, this NPRM incorporates a proposal to remove from use aluminum alloy 6351-T6 that was published in an advance notice under Docket HM-176A and terminates that docket (RIN: 2131-AB51). This action is being taken to--simplify the HMR for construction of cylinders; provide for flexibility in the design, construction and use of cylinders; recognize recent advances in cylinder manufacturing and requalification technologies; promote safety though simplification of the regulations; reduce the need for exemptions; and facilitate international commerce. The intended effect of this action is to enhance the safe transportation of hazardous materials in cylinders.","machine_formats":{"json":"https://regulus.evalyn.ai/document/federal-register-98-28118.json","markdown":"https://regulus.evalyn.ai/document/federal-register-98-28118.md"},"app_url":"https://regulus.evalyn.ai/document/federal-register-98-28118","source_url":"https://www.federalregister.gov/documents/1998/10/30/98-28118/hazardous-materials-requirements-for-dot-specification-cylinders","body":"Federal Register, Volume 63 Issue 210 (Friday, October 30, 1998) [Federal Register Volume 63, Number 210 (Friday, October 30, 1998)] [Proposed Rules] [Pages 58460-58521] From the Federal Register Online via the Government Publishing Office [ www.gpo.gov ] [FR Doc No: 98-28118] [[Page 58459]] _______________________________________________________________________ Part II Department of Transportation _______________________________________________________________________ Research and Special Programs Administration _______________________________________________________________________ 49 CFR Part 107, et al. Hazardous Materials: Requirement for DOT Specification Cylinders; Proposed Rule Federal Register / Vol. 63, No. 210 / Friday, October 30, 1998 / Proposed Rules [[Page 58460]] DEPARTMENT OF TRANSPORTATION Research and Special Programs Administration 49 CFR Parts 107, 171, 172, 173, 177, 178, and 180 [Docket No. RSPA-98-3684(HM-220)] RIN 2137-AA92 Hazardous Materials: Requirements for DOT Specification Cylinders AGENCY: Research and Special Programs Administration (RSPA) DOT. ACTION: Notice of proposed rulemaking (NPRM) and public meeting. ----------------------------------------------------------------------- SUMMARY: RSPA proposes to amend certain requirements in the Hazardous Materials Regulations (HMR) to establish four new DOT cylinder specifications and to revise the requirements for maintenance, requalification, and repair of all DOT specification cylinders. In addition, RSPA proposes to: revise the requirements for approval of cylinder requalifiers, independent inspection agencies, and nondomestic chemical analysis and tests; revise the cylinder requalification, maintenance and repair requirements; and to revise the requirements for hazardous materials that are authorized to be offered for transportation in cylinders. Finally, this NPRM incorporates a proposal to remove from use aluminum alloy 6351-T6 that was published in an advance notice under Docket HM-176A and terminates that docket (RIN: 2131-AB51). This action is being taken to--simplify the HMR for construction of cylinders; provide for flexibility in the design, construction and use of cylinders; recognize recent advances in cylinder manufacturing and requalification technologies; promote safety though simplification of the regulations; reduce the need for exemptions; and facilitate international commerce. The intended effect of this action is to enhance the safe transportation of hazardous materials in cylinders. DATES: Comment Date: Comments must be received on or before January 28, 1999. Public Meeting Date: A public meeting will be held on December 8, 1998; from 9:30 am to 4:00 pm. An additional meeting may be scheduled if there is substantial interest. ADDRESSES: Written Comments: Address comments to the Dockets Management System, U.S. Department of Transportation, PL 401, 400 Seventh St., SW, Washington, DC 20590-0001. Comments should identify the docket number, RSPA 98-3684(HM-220), and should be submitted in two copies. Persons wishing to receive confirmation of receipt of their comments should include a self-addressed stamped postcard. The Dockets Management System is located on the Plaza Level of the Nassif Building, at the above address. Public dockets may be reviewed between the hours of 10:00 a.m. to 5:00 p.m., Monday thru Friday, excluding Federal holidays. In addition, comments can be reviewed by accessing the DOT Homepage ( http:// www.dot.gov ). Comments may also be submitted by E-mail to `` [email protected] ''. In every case, the comment should refer to the Docket number set forth above. Public Meeting: The public meeting will be held in Room 3200-3204 at the U.S. Department of Transportation's Nassif Building, 400 7th Street SW, Washington DC, 20590. FOR FURTHER INFORMATION CONTACT: Cheryl Freeman, telephone number (202) 366-4545, Office of Hazardous Materials Technology, or Ryan Posten, telephone number (202) 366-8553, Office of Hazardous Materials Standards, Research and Special Programs Administration, U.S. Department of Transportation, Washington, DC 20590-0001. SUPPLEMENTARY INFORMATION: I. Background Federal hazardous material transportation law (Federal hazmat law), 49 U.S.C. 5101-5127, authorizes the Secretary of Transportation to regulate the manufacture and continuing qualification of packagings used to transport hazardous materials in commerce, or packagings certified under Federal hazmat law for the transportation of hazardous materials in commerce. The HMR, 49 CFR parts 171-180, contain requirements for the manufacture, use, and requalification of cylinders subject to Federal hazmat law, including defining materials and methods of construction, the frequency and manner of inspection and testing, standards for cylinder rejection and condemnation, cylinder marking and recordkeeping, authorizations for packaging hazardous materials in cylinders, filling, loading, unloading, and carriage in transportation. Historically, Federal authority to regulate the transportation of compressed gases was given to the former Interstate Commerce Commission (ICC) through the Transportation of Explosives Act, 35 Stat. 1135, section 233 (March 4, 1909), which was later amended in 1921, at 41 Stat. 1445, Sec. 233. In 1911 the ICC adopted a series of ``Shipping Container Specifications,'' among which the ICC 3 specification for seamless steel cylinders was codified. That same year, the ICC 4 specification for a lap-welded cylinder for anhydrous ammonia was also published. As the welding process improved, from the riveted/brazed welds to resistance welding and then butt welding by the metal-arc process, the ICC 4 Specification series was expanded to include the 4BA, the 4BW, and others. By 1914, two other cylinder specifications were codified: the ICC 7 specification for steel cylinders for low pressure, nonliquefied gas, (which have carried over to the present regulations, but not as specification 7) and the ICC 8 specification for acetylene gas cylinders, which still exists today with minor changes. In 1930, the ICC implemented regulations for periodic inspection and testing of cylinders; the regulations, as amended, were first published in the Federal Register on December 12, 1940 (5 FR 4908). During the 1930's and 1940's, the Compressed Gas Association (CGA) developed and refined the water jacket test method for determining the serviceability of a cylinder. During World War II, there was a shortage of high pressure gas cylinders. Because of CGA's work on steel wall stress limitations, the ICC granted ``temporary'' regulatory relief to increase the gas carrying capacity of existing cylinders by allowing the cylinders to be filled 10% over their marked service pressures, and by marking those cylinders with a plus, ``+'', mark. Ten years later, the regulations were codified into the Code of Federal Regulations (15 FR 8261; Dec. 2, 1950). In 1967, pursuant to the Department of Transportation Act, Pub. L. 89-670, 80 Stat. 931, regulatory responsibility for the transportation of dangerous articles in commerce was transferred from the ICC to DOT. Through rulemaking and the issuance of exemptions from the regulations under 49 CFR part 107, subpart B, materials other than steel (e.g., aluminum and composite cylinders) now are authorized for use. Nevertheless, apart from the substitution of the ``DOT'' identifier for the ``ICC'' identifier, many of today's basic requirements remain virtually unchanged from the time they were first incorporated into the regulations. Over the years, RSPA has received numerous petitions for rulemaking requesting various changes to the cylinder requirements. CGA filed most of these petitions that request changes to [[Page 58461]] the cylinder specifications. In 1969, CGA submitted a petition (P-69) containing six new proposals and revising eight previously-filed petitions. Many of these 14 petitions were handled in subsequent rulemakings such as Docket HM-69 adding a DOT 39 non-reusable, non- refillable specification cylinder (August 24, 1971; 36 FR 16579), Docket HM-85 updating the DOT-4L cylinder material properties (Nov. 5, 1971; 36 FR 21287), and Docket HM-99 adding the DOT-3T specification cylinder (Aug. 15, 1973; 38 FR 21989). In 1981, RSPA adopted a DOT 3AL specification under Docket HM-176 (46 FR 62452). This new specification for a seamless aluminum cylinder, made of definitely prescribed alloys, was based in part on the petitions received from industry and an agency initiative to consolidate and eliminate the need for seven exemptions authorizing the manufacture of seamless aluminum cylinders. In 1984, CGA petitioned (P- 953) to include a welded stainless steel cylinder similar to the DOT- 4BW. At that time, CGA proposed the designation ``4SS'' for the new stainless steel cylinder. In 1990, CGA petitioned to add a new 3F specification for a seamless steel compressed gas cylinder designed for a high stress level similar to the DOT-3T, but with a stronger structural integrity similar to the DOT-3AA cylinder. The proposed 3FM specification provides for a greater efficiency in gas transportation. The above-mentioned petitions were given full consideration in the development of this NPRM. In developing this NPRM, RSPA worked closely with the cylinder manufacturing and maintenance industries, and held several meetings with CGA to obtain clarification of the CGA petitions. RSPA also held public outreach meetings with industry that were announced in the Federal Register. The industry proposals and petitions have been refined by RSPA based on RSPA's compliance inspections and exemption program, interpretations issued by RSPA, and certain industry consensus standards and practices that have proven to be safe. RSPA believes the proposals in this NPRM are consistent with sound industry practice and incorporate modern manufacture and requalification technology. Some of the more significant proposals contained in this NPRM are: 1. The establishment of four new cylinder specifications that are more performance-oriented and the removal of several obsolete specifications. These proposed specifications are expressed in metric units, require marking of the cylinder with test pressure in place of service pressure, and are distinguishable by their specification designation markings. 2. The new specifications allows greater flexibility in the design and construction of metric-marked cylinders. 3. Independent inspection of all metric-marked cylinders, both seamless and welded. 4. Design qualification testing of metric-marked cylinders. 5. The requalification of metric-marked cylinders and certain nonmetric-marked cylinders using thickness and shear wave ultrasonic testing in place of the volumetric pressure test. 6. Requiring any person who performs a requalification function that requires marking an inspection or retest date on the cylinder to have approval from the Associate Administrator for Hazardous Materials Safety (herein after referred to as the Associate Administrator). 7. Standardizing the requirements for the repair and rebuilding of DOT 4 series cylinders, other than the DOT 4L. 8. Allowing a 10-year interval for requalification of DOT 3-series metric-marked cylinders used in certain types of service. 9. Allowing a 15-year interval for requalification of certain DOT 4-series metric-marked cylinders used in certain types of service. 10. Allowing, upon approval by the Associate Administrator, the application of requalification markings on cylinders by using alternative methods that produce durable legible marks. 11. Implementing valve damage protection and puncture resistance criteria for all DOT specification cylinders used for Division 2.3 or 6.1 materials in Hazard Zone B, and puncture resistance criteria for those in Hazard Zone A. 12. Discontinuing authorization for a filled cylinder with a specified service life from being offered for transportation in commerce after its service life has expired. 13. Providing filling pressures for metric-marked cylinders based on critical temperature, test pressure, and draft ISO Standard 11622. 14. Requiring that pressure relief devices on all metric-marked specification cylinders be set at no less than test pressure. Requiring that pressure relief devices on all 3-series, nonmetric-marked specification cylinders be set at no less than test pressure from the first requalification due after the effective date of the final rule. II. New specification Standards for Metric-marked Cylinders A. Consolidation of Cylinder Standards As discussed above, the current cylinder requirements have their origin in the early 1900's. The regulations were developed in a piecemeal fashion, with adjustments being made to address particular situations and problems on a case-by-case basis. This NPRM represents RSPA's first comprehensive review of the cylinder requirements. RSPA proposes to establish four new cylinder specifications for seamless and welded cylinders. These proposed cylinder specifications are more performance oriented and incorporate provisions that recognize certain domestic and international practices. Cylinders made to these specifications would be marked in metric units and would be distinguished by a unique specification marking that closely approximates the markings in draft International Standards Organization (ISO) and the European Committee for Standardization (CEN), Technical Committee, entitled ISO/TC58/SC4 ``Gas Cylinders Operational Requirements,'' based on CEN Standard EN 1089-1, ``Transportable gas cylinders--Gas cylinder identification--Part 1: Stampmarking.'' The new seamless cylinder specifications are identified as DOT 3M, 3ALM, and 3FM. The welded cylinder specification is identified as the DOT 4M. Eventually, RSPA anticipates that the DOT 3M specification will replace the current DOT 3A, 3AA, 3AX, 3AAX, 3B, and 3BN specifications. The DOT 3ALM specification will replace the 3AL specifications. The DOT 3FM will replace the higher strength 3AA and the 3T specifications. The DOT 4M will replace the 4B, 4BA, 4BW, 4B240X, 4B240ET, and 4E. In future rulemakings, RSPA plans to propose new metric-marked cylinder specifications to replace the current specifications for the DOT 3E, 3HT, 4D, 4DA and 4DS; the 4L; the 8 and 8AL; and the DOT 39. The basic specification requirements, those common to most metric- marked cylinders, are in proposed Sec. 178.69. This section contains definitions, material of construction, duties of the inspector, and criteria for all design and production qualification tests that may be required by the individual specifications. Proposed Sec. 178.70 contains requirements applicable to seamless cylinders. The individual specifications, containing additional requirements, are in Sec. 178.71 for the DOT 3M, Sec. 178.72 for the DOT 3ALM, and Sec. 178.73 for the DOT 3FM. Proposed Sec. 178.81 contains [[Page 58462]] requirements applicable to DOT 4M welded cylinders. In all cases where the new proposed specifications differ, the new specification requirements will have a level of integrity that is equivalent to, or greater than, the current nonmetric specification requirements. Significant changes from current requirements are discussed further in this preamble. B. Cylinder Filling Limits CGA petitioned RSPA to change the test pressure from 5/3 times service pressure for currently authorized DOT specification seamless cylinders to 3/2 times service pressure for newly constructed DOT specification seamless cylinders. In effect, the CGA proposal would increase the filling limit for most of the new seamless DOT specification cylinders to that currently authorized for cylinders marked with a ``+'' sign (see 49 CFR 173.302(c)). In the historical and technical information provided to support its petition, CGA stated: I. Background In 1942 during the height of industrial production for WWII, a shortage of high pressure gas cylinders developed. The shortage was hampering the War effort. The three manufacturers of large size cylinders were also forging shells and bombs and did not have capacity to forge those and the required quantities of high pressure steel cylinders. The War Production Board brought this concern to the Compressed Gas Association (CGA) to seek a remedy for the shortage of high pressure cylinders. One idea was to start up new production by spinning seamless tubing, which was initiated by Cueno-Press and Taylor Forge; but that would take months. An immediate ``temporary'' relief was conceived which was to increase gas carrying capacity by allowing an ``overfill'' of existing cylinders. After careful study, the increase of 10% in filling pressure (i.e., from 2015 to 2215 psi) was considered safe and technically sound because of the conservative design required by DOT Specification 3A and of the existing high pressure cylinders produced thereto. For example: A 10% increase in wall stress at the increased filling pressure maintained the operating stress well below the yield point of the steel; and so, cyclic fatigue failure would not become a factor for the ductile, low strength steel. Furthermore, the operating stress would still be far below the ultimate tensile strength providing an adequate safety factor which related service pressure to rupture pressure; and the only way the cylinder pressure of permanent gases could reach burst pressure was by involvement in a fire. By joint agreement between the War Production Board, Interstate Commerce Commission (ICC) and the Gas Industry, it was decided to immediately allow a ``10% overfill'' for the existing cylinder fleet. This was to be allowed for both flammable and non-flammable permanent gases. To make this effective required a change in the ``Regulations'' covering ``Charging of Cylinders with Non-liquefied Compressed Gases'' because it was to be applied to existing cylinders as well as new production. Therefore, section 173.302 was changed and 178 was not changed to cover cylinder design and production. Thus, a 10% increase in the gas carrying capacity of the existing cylinder fleet and new current production was immediately achieved. This had the effect of adding 10% additional cylinders. II. Technical Rationale for Allowing 10% Higher Fill Pressures A. Introduction The fleet of DOT 3 Series cylinders in use during the war years performed safely without a service failure, notably from fatigue or gas pressure rupture. Thus, the carefully considered decision to allow the charging pressure to be increased by 10% was considered to be proven safe and technically valid. The compressed gas industry monitored performance of their cylinder fleets and concluded that the ``temporary'' over-filling procedure could safely become a permanent regulation. However, CGA decided to recommend certain controls to justify permanent continuation of this change which effected the design safety factor. Those controls are now contained in CFR Title 49, clause 173.302 (c) entitled ``Special filling limits for Specification 3A, 3AA, 3AX, 3AAX and 3T cylinders''. The technical rationale for those controls was: * * * (1) ``That such cylinders are equipped with frangible disc safety relief devices (without fusible metal backing) having a bursting pressure not exceeding the minimum prescribed test pressure.'' Rationale: This was to guarantee that cylinder pressure from any source could never reach the cylinder design burst pressure. Therefore, lowering the ratio of service pressure to rupture pressure, was meaningless because the cylinders would be equipped with a ``rupture port'' which would vent the gas pressure at a pre- determined pressure and prevent the cylinder from ever reaching its ``burst'' pressure. * * * (2) ``That the elastic expansion shall have been determined at the time of the last test or retest by the water jacket method.'' Rationale: In the 1930s and 1940s the CGA had developed and refined the water jacket test method, and developed the mathematical relationship of wall stresses as measured by the elastic expansion of individual cylinder designs. The average wall stress as determined by elastic expansion measured by the water jacket hydrostatic test was limited to a specified stress less than the permitted maximum design stress. For example, 3AA design cylinders were to be rejected if the elastic expansion exceeded a value equivalent to the strain developed at an average wall stress of 67,000 psi; whereas, the design wall stress limit in 178.37-10(b) is 70,000 psi. This 4% decrease in wall stress was selected because elastic expansion measures the average effective wall thickness and not the minimum. At the same time it was concluded that a small increase (i.e., 4%) in the stress at isolated areas of a cylinder could be safely tolerated to allow for localized damage or thinning; and a ``Maximum wall stress limitation'' was set; e.g., 73,000 psi for 3AA design cylinders. This procedure of elastic expansion control was developed to further justify the permanent use of the ``10% overfill'' by guaranteeing that such cylinders would be controlled by limiting the loss of wall thickness so that the stress at service pressure would be below the yield point of the cylinder steel. * * * (3) ``That either the average wall stress or the maximum wall stress shall not exceed the wall stress limitations shown in the following table.'' Rationale: Wall stress limitations for both average wall and isolated spots were developed for each ``class of steel'' used for ICC 3, DOT 3A, and DOT 3AA cylinder designs. (Much later DOT-3T was added.) These limits were selected from known physical properties of these steel classes; and were set to assure that stress at operation pressures were: (1) well below yield point and (2) that an adequate burst pressure to service pressure ratio was obtained. This clause amplifies the preceding clause 2. (4) ``That an external and internal visual examination made the time of test or retest shows the cylinder to be free from excessive corrosion, pitting, or dangerous defects.'' Rationale: The body of data and service experience available within the CGA had proven that the design criterion for DOT high pressure cylinders was eminently safe; especially as regards cycle life and rupture in service. The only cause of cyclic or tensile rupture would be damage inflicted during manufacture or service. Thus, the visual inspection before and during use was considered to be an essential safety measure, which continues to be true today. (5) ``That a plus sign (+) be added following the test date marking on the cylinder to indicate compliance with paragraphs (c) (2), (3) and (4) of this section.'' Rationale: This was to force both the cylinder manufacturer and user to take a physical act to signify their guarantee of compliance with the control methods. This also was an easily discerned mark that permitted personnel to identify which cylinders were satisfactory, safe and qualified for charging to the ``10% overfill''. B. Wall Stress and Safety Factors of Series 3 DOT Cylinders The most common high pressure cylinder in use in 1942 was the ICC-3A-2015 with size of 9'' O.D. x 51'' long, rated at 220 cubic feet oxygen capacity. This cylinder made of normalized intermediate manganese steel had an ultimate tensile strength of about 95,000 psi and had excellent ductility and good charpy impact strength at -50 deg.F. to assure safe fracture performance. The design stress at test pressure was 49,500 psi which with the 5/3 test pressure ratio allows a stress of 29,600 psi at 2015 psi service pressure. The yield point was about 69,000 psi (about 0.73 x U.T.S.). Thus the service stress was about 50% of yield stress, which level assured a long (virtually infinite) cycle life. The burst stress to service stress ratio (safety factor) was about 3.2 (95,000 29,600).* * * [[Page 58463]] This ratio of operating stress compared to ultimate strength was obviously a conservative design. The conservatism is more obvious in view of the fact that the cylinders were seamless, forged, high quality steel pressure vessels which have no stress concentration points in the longitudinal plane of major stress. Furthermore, they were used in non-corrosive gas service and have no source to increase the contained pressure during use except by the small fluctuations in ambient temperature or a fire. The cylinders are also subjected to periodic requalification. In view of these facts/ data and the excellent service record, the decision was made in 1942 to allow stress to increase about 32,600 psi at service pressure for the ``10% overfill''. This equates to a working stress to burst strength ratio of 2.9 (95,000 32,600). Thus the ``10% overfill'' was considered technically appropriate and eminently safe as a way to increase the oxygen carrying capacity from 220 CF to 244 CF. These cylinders have continued in service for over 50 years with a perfect safety record as regards cyclic or pressure rupture in service. The same effective stress at test pressure can be achieved by testing either at 5/3 of 2015 or 3/2 of 2215. These pressures are 3358 and 3323 which stresses the wall to 49,350 and 48,720 psi respectively. This 1.2% difference in test pressure stress would be inconsequential with respect to cylinder safety. Therefore, the test pressure in the DOT 3A, 3AA, and 3T specifications can safely be changed to 3/2 instead of 5/3 service pressure. The following paragraph describes graphic presentation of the situation with intermediate manganese normalized and chrome-moly quenched and tempered, which represents virtually 100% of the 3A and 3AA cylinders in the U.S. * * * It is proposed to write all the ``10% overfill'' into the design conditions for DOT 3A, 3AX, 3AA, 3AAX, 3F (new) and 3T. This can be accomplished by merely changing the required test pressure from 5/3 x service pressure to 3/2 x service pressure. For all intents and purposes, the cylinders would be exactly the same as discussed above. * * * III. Conclusions 1. DOT 3A and 3AA cylinders have been in use since 1942 (54 years) with a ratio of test pressure to service pressure of 3/2. At time of manufacture or retest, the cylinders are tested at 5/3 x service pressure; but the service pressure is increased by 10% for filling. 2. The 10% overfill pressure times 3/2 results in a wall stress at test pressure only 1% less than the requirement to test at 5/3 times marked service pressure. 3. The 3/2 test pressure would result in a calculated minimum wall of barely 0.001 inch less for a current cylinder with a 0.250 wall minimum. 4. The tiny decrease in wall thickness and effect of 1% lower stress at test pressure would have no effect in overall cylinder safety. 5. The service record since 1942 (54 years) has been perfect as regards rupture under gas pressure and cyclic fatigue characteristic. The change to 3/2 test versus 5/3 does not change any measurable characteristic which would effect these failure modes. 6. The ASME Code uses a 3/2 test pressure to working pressure ratio. 7. Europe (18 countries) uses the 3/2 test to service pressure ratio. IV. Recommendation The minimum prescribed test pressure shall be 3/2 times the marked service pressure for all cylinders with a marked service of 500 psi or greater for all Series 3 steel cylinders. This should also be considered for cylinders made of nickel, aluminum or stainless steel. In considering the issue of cylinder filling limits, RSPA also reviewed technical information supplied by cylinder manufacturers and by holders of exemptions that authorize either a test pressure of 3/2 times service pressure or 10% overfill for materials not currently specified in 49 CFR 173.302(c), the hazardous materials information system data base for incidents involving ``+'' marked cylinders, and the work currently being done by the ISO and the United Nations Group of Experts on the Transport of Dangerous Goods. After reviewing all the available information, RSPA has concluded that from a transportation safety perspective, there is no technical reason or safety experience which would prohibit increasing the cylinder filling limits for seamless cylinders to those comparable to the levels currently authorized in 49 CFR 173.302(c). Therefore, RSPA has accepted the CGA proposal to increase the filling limits for new cylinders, in principle, but has chosen to limit the proposal for increased filling limits to metric-marked DOT Specification cylinders. Additionally, RSPA has not changed the requirements in 49 CFR 173.302(c) for the current DOT specification cylinders, but has moved them to proposed Sec. 173.302a(b). With regards to existing cylinders, RSPA is considering a process for accepting certain DOT specification cylinders as meeting the new metric specifications, but is still considering various conversion criteria. RSPA solicits comments from interested persons as to the interest and feasibility of developing such a conversion program and, if feasible, specific criteria for requalifying and conversion of existing cylinders. C. Specification Markings on Metric-marked Cylinders In the CGA submission to RSPA, it was requested that cylinders be marked in bar rather than psig. Bar is an internationally accepted metric unit for pressure in the compressed gas industry. This change would help make marking DOT specification cylinders consistent with the practice in most European countries which are currently marking cylinders with the test pressure shown in bar. While considering this request, RSPA reviewed its current marking requirements as well as two draft documents on the subject of cylinder marking being considered by the ISO and the CEN. The documents are ISO/ DIS 13769, ``Gas cylinders--Stamp marking,'' and CEN Standard EN 1089- 1, ``Transportable gas cylinders--Gas cylinder identification--Part 1: Stampmarking.'' Based upon this review, RSPA proposes to change the way DOT specification cylinders are marked. The new marking scheme will change the number and sequence of marks required to be placed on DOT specification cylinders by manufacturers and is consistent with the sequence being proposed by both ISO and CEN. However, RSPA does not proposed to require all of the cylinder marks contained in either the ISO or CEN documents. The proposed marking scheme will also make it easier to identify those cylinders manufactured to the proposed specifications. Additionally, the marking scheme is similar to the type of marking scheme contained in the United Nations Recommendations for the Transport of Dangerous Good for non-bulk packagings and intermediate bulk containers. The proposed marking sequence, with each element separated by a slash mark, is as follows: DOT Specification Country of origin Manufacturer's identification Serial number Stamp for non-destructive testing (if applicable) Minimum wall thickness Water capacity (liters) Test pressure (bar) Identification of alloy Tare weight (kg) Identification of inspection agency Test date REE (if applicable) The most significant change is the marking of the new specification cylinders with test pressure instead of service pressure. DOT specification cylinders have always been designed to test pressure rather than service pressure. Specifically, the stress formulas used to determine the minimum wall thickness of DOT specification cylinders are calculated at the minimum test pressure. [[Page 58464]] Additionally, as currently authorized in 49 CFR 173.302(c), many cylinders used to transport compressed gases which are not liquefied, dissolved, toxic or flammable are filled to a pressure 10% in excess of their marked service pressure and 49 CFR 173.304(f) specifies, with limited exceptions, that the pressure in the container at 130 deg.F shall not exceed 5/4 times the marked service pressure. While marking the test pressure rather than the service pressure will require the training of persons who fill cylinders, it should not have any adverse safety effects since inadvertently filling a cylinder to the marked test pressure, in bar, would result in the cylinder being filled to a lower pressure than the currently marked service pressure in psig. Further, most cylinders are filled by a person who uses a filling table that shows the values already adjusted for changes in temperature and elevation. RSPA envisions that cylinders marked with test pressure will also be filled by using filling tables. III. Independent Inspection--New DOT Specification Cylinders A DOT specification cylinder is, and has been for the past sixty years, a widely recognized standard for the safe transportation of compressed gases. This wide acceptance has resulted in significant economic benefit to domestic industry far beyond the value of the cylinders sold internationally. Market demand for gases and equipment has increased as a direct result of the reputation of the DOT cylinder for strength, durability and quality. Since the early 1900's, cylinders manufactured under DOT's ``high pressure'' specifications have required independent inspection, originally referred to as ``disinterested inspection.'' Occasionally, RSPA receives complaints from companies about costs of independent inspection or claims that the companies' employees are as knowledgeable and qualified, if not more so, as the independent inspector. However, RSPA's Office of Hazardous Materials Enforcement, through its compliance inspection program, has found a higher level of compliance with the regulations when inspection and certification functions are carried out by an Independent Inspection Agency (IIA) instead of by an employee of the manufacturing company. In order for DOT specification cylinders to be acceptable for service in most foreign countries, cylinders must be certified through an inspection process which is not controlled by the cylinder manufacturer. Since 1977, all DOT specification cylinders manufactured outside the United States under the RSPA foreign cylinder approvals program are required to be inspected and certified by an IIA. In order to maintain the high level of safety established over the past 100 years, to maintain the acceptability of DOT specification cylinders worldwide, and to facilitate the harmonization between domestic and foreign cylinder specifications, RSPA is proposing that all cylinders manufactured or rebuilt to the new DOT metric-marked cylinder specifications be subject to inspection by an IIA. In effect, this would continue the current DOT inspection requirements for seamless cylinders and extend the practice to welded cylinders. IV. DOT Approval of Cylinder Requalifiers RSPA proposes that any person who requalifies a DOT specification cylinder must be approved by the Associate Administrator prior to performing any requalification function that requires an inspection or retest date to be marked on the cylinder. The affected functions include performance of a visual inspection, pressure test, ultrasonic thickness test, repair, or the rebuilding of cylinders. This proposal will enhance the accountability of the cylinder requalification process. Currently, Sec. 173.34(e)(13) permits a cylinder used exclusively for certain liquefied gases to be requalified for use by performing an external visual inspection and marking the cylinder with the test date and an ``E''. The ``E'' indicates that the cylinder was requalified by external visual inspection in accordance with CGA Pamphlet C-6 rather than by a hydrostatic test. A person who performs only external visual inspections is not required to obtain an approval from, or register with, the Associate Administrator. Although current Sec. 173.34(e)(13) requires these persons to maintain records, RSPA does not know who or how many persons requalify and mark cylinders with an inspection date and an ``E'', or the locations of their places of business. Also, RSPA does not know whether these persons have the knowledge and skills necessary to perform the required functions, including use of required inspection standards. RSPA inspectors have frequently observed DOT specification cylinders, primarily in liquefied petroleum gas service, that bear markings representing that they were requalified for use. The markings reflected dates of recent requalification by external visual inspection. One cylinder, marked with the letter ``E'' and the date ``6 98,'' was examined by RSPA personnel on June 19, 1998, and found to be rusted to an extent that there is no doubt that the rust formed long before the marked inspection date. Considering the amount of undisturbed rust on the cylinder, it was apparent that the person requalifying the cylinder did not properly prepare it for inspection by first completely removing all rust from the exterior surface of the cylinder, as required by paragraph 3.1 of CGA Pamphlet C-6, which was developed by the compressed gas industry for adoption by reference as Federal regulations. In reviewing the approach for resolving this issue, RSPA considered five options: (1) Continue the current provision that allows persons who are not known to RSPA to requalify cylinders by performing visual inspections; (2) Adopt a registration program that would require persons who perform visual requalification to be registered with RSPA and to mark their requalifier identification numbers (RIN) on the cylinders they inspect; (3) Adopt an approvals program requiring that persons performing requalifications of cylinders by visual inspection be approved by RSPA upon written application containing statements regarding their qualifications; (4) Adopt an approvals program that would require persons performing visual requalifications to be reviewed by an independent inspection agency; and (5) Discontinue visual requalification of cylinders, thereby requiring all affected cylinders to be hydrostatically retested. RSPA selected option 3 for this NPRM because it will not impose the burden and added cost of employing an independent inspection agency while ensuring the accountability of a person performing visual requalifications and providing RSPA the authority to revoke or suspend the person's approval for demonstrated non-compliance with the requalification requirements. Also, by requiring a certification that an applicant has the ability to perform requalifications, RSPA believes each applicant's awareness of the importance of compliance will be heightened. RSPA solicits comments on these options and others that RSPA may not have considered. V. Requalification Markings RSPA proposes to amend Sec. 171.2(d) to prohibit the misrepresentation of a requalification identification number (RIN) marking. Over the years, through its compliance program, RSPA has been [[Page 58465]] in contact with dozens of individuals who did not perform the required hydrostatic tests, but stamped the cylinders as though each cylinder had passed the inspections and tests. The steel stamps used to mark the cylinders are readily available, low-cost and simple to use. RSPA believes that these and other factors (e.g., the high cost of purchasing and maintaining hydrostatic test equipment when compared to the mere cost of obtaining a set of steel stamps) provide an economic inducement for some individuals to engage in fraudulent activities. Based on recent enforcement data, this safety problem appears to be more widespread than RSPA originally thought. RSPA is concerned about the number of cylinders that are fraudulently stamped and then are used to transport hazardous materials in commerce. These cylinders, whose structural integrity has not been verified, pose substantial risks to health, safety and property. When RSPA discovers these situations, RSPA publishes a safety alert notice (see Notice No. 97-2, 62 FR 19651; Notice No. 97-3, 62 FR 24548) and, where appropriate, refers the matter to the Department of Justice for possible criminal prosecution (see Unit","truncated":true,"body_characters":326986}