49 C.F.R. § 173.301 General requirements for shipment of compressed gases in cylinders and spherical pressure vessels.
Title 49 - Transportation
Link to an amendment published at 71 FR 33881, June 12, 2006. (a) General qualifications for use of cylinders. As used in this subpart, filled or charged means an introduction or presence of a hazardous material in a cylinder. A Class 2 material (gas) offered for transportation in a cylinder must be prepared in accordance with this section and §§173.301a through 173.305, as applicable. (1) Compressed gases must be in metal cylinders and containers built in accordance with the DOT and ICC specifications, as shown in this paragraph (a)(1), in effect at the time of manufacture, and requalified and marked as required by the specification and the regulation for requalification, if applicable:
Packagings 2P 2Q ICC–3 1 Use of existing cylinders is authorized. New construction is not authorized. 3A 3AA 3AL 3AX 3A480X 3AAX 3B 3BN 3E 3HT 3T 4AA480 4B 4B240ET 4BA 4BW 4D 4DA 4DS 4E 4L 8 8AL 39 (2) A cylinder must be filled in accordance with this part. Before each filling of a cylinder, the person filling the cylinder must visually inspect the outside of the cylinder. A cylinder that has a crack or leak, is bulged, has a defective valve or a leaking or defective pressure relief device, or bears evidence of physical abuse, fire or heat damage, or detrimental rusting or corrosion, may not be filled and offered for transportation. A cylinder may be repaired and requalified only as prescribed in subpart C of part 180 of this subchapter. (3) Pressure relief devices must be tested for leaks before a filled cylinder is shipped from the cylinder filling plant. It is expressly forbidden to repair a leaking fusible plug device where the leak is through the fusible metal or between the fusible metal and the opening in the plug body, except by removal and replacement of the pressure relief device. (4) A cylinder that previously contained a Class 8 material must be requalified in accordance with §180.205(e) of this subchapter. (5) When a cylinder with a marked pressure limit is prescribed, another cylinder made under the same specification but with a higher marked pressure limit is authorized. For example, a cylinder marked “DOT-4B500” may be used when “DOT-4B300” is specified. (6) No person may fill a cylinder overdue for periodic requalification with a hazardous material and then offer it for transportation. The prohibition against offering a cylinder for transportation that is overdue for periodic requalification does not apply to a cylinder filled prior to the requalification due date. (7) A cylinder with an authorized service life may not be offered for transportation in commerce after its authorized service life has expired. However, a cylinder in transportation or a cylinder filled prior to the expiration of its authorized service life may be transported for reprocessing or disposal of the cylinder's contents. After emptying, the cylinder must be condemned in accordance with §180.205 of this subchapter. (8) The pressure of the hazardous material at 55 °C (131 °F) may not exceed 5/4 of the service pressure of the cylinder. Sufficient outage must be provided so the cylinder will not be liquid full at 55 °C (131 °F). (9) Specification 2P, 2Q, 3E, 3HT, spherical 4BA, 4D, 4DA, 4DS, and 39 cylinders must be packed in strong non-bulk outer packagings. The outside of the combination packaging must be marked with an indication that the inner packagings conform to the prescribed specifications. (b) Cylinder markings. Required markings on a cylinder must be legible and must meet the applicable requirements of subpart C of part 180 of this subchapter. Additional information may be marked on the cylinder provided it does not affect the required markings prescribed in the applicable cylinder specification. (c) Toxic gases and mixtures. Cylinders containing toxic gases and toxic gas mixtures meeting the criteria of Division 2.3 Hazard Zone A or B must conform to the requirements of §173.40 and CGA Pamphlets S–1.1 and S–7 (IBR, see §171.7 of this subchapter). A DOT 39 cylinder may not be used for toxic gases or toxic gas mixtures meeting the criteria for Division 2.3, Hazard Zone A or B. (d) Gases capable of combining chemically. A filled cylinder may not contain any gas or material capable of combining chemically with the cylinder's contents or with the cylinder's material of construction, so as to endanger the cylinder's serviceability. After September 30, 2002, DOT 3AL cylinders made of aluminum alloy 6351–T6 may not be filled and offered for transportation with pyrophoric gases; however, if it is otherwise serviceable and conforms to the regulations in effect on September 30, 2002, a DOT 3AL cylinder made of aluminum alloy 6351–T6 and filled before October 1, 2002, may be transported for reprocessing or disposal of the cylinder's contents until April 1, 2003. (e) Ownership of cylinder. A cylinder filled with a hazardous material may not be offered for transportation unless it was filled by the owner of the cylinder or with the owner's consent. (f) Pressure relief device systems. (1) Except as provided in paragraphs (f)(5) and (f)(6) of this section, a cylinder filled with a gas and offered for transportation must be equipped with one or more pressure relief devices sized and selected as to type, location, and quantity, and tested in accordance with CGA S–1.1 (compliance with paragraph 9.1.1.1 of CGA S–1.1 is not required) and S–7. The pressure relief device must be capable of preventing rupture of the normally filled cylinder when subjected to a fire test conducted in accordance with CGA C–14 (IBR, see §171.7 of this subchapter), or, in the case of an acetylene cylinder, CGA C–12 (IBR, see §171.7 of this subchapter). (2) After December 31, 2003, a pressure relief device, when installed, must be in communication with the vapor space of a cylinder containing a Division 2.1 (flammable gas) material. (3) For a specification 3, 3A, 3AA, 3AL, 3AX, 3AXX, 3B, 3BN, or 3T cylinder filled with gases in other than Division 2.2, beginning with the first requalification due after December 31, 2003, the burst pressure of a CG–1, CG–4, or CG–5 pressure relief device must be at test pressure with a tolerance of plus zero to minus 10%. An additional 5% tolerance is allowed when a combined rupture disk is placed inside a holder. This requirement does not apply if a CG–2, CG–3 or CG–9 thermally activated relief device or a CG–7 reclosing pressure valve is used on the cylinder. (4) A pressure relief device is required on a DOT 39 cylinder regardless of cylinder size or filled pressure. A DOT 39 cylinder used for liquefied Division 2.1 materials must be equipped with a metal pressure relief device. Fusible pressure relief devices are not authorized on a DOT 39 cylinder containing a liquefied gas. (5) A pressure relief device is not required on— (i) A cylinder 305 mm (12 inches) or less in length, exclusive of neck, and 114 mm (4.5 inches) or less in outside diameter, except when the cylinder is filled with a liquefied gas for which this part requires a service pressure of 1800 psig or higher or a nonliquefied gas to a pressure of 1800 psig or higher at 21 °C (70 °F); (ii) A cylinder with a water capacity of less than 454 kg (1000 lbs) filled with a nonliquefied gas to a pressure of 300 psig or less at 21 °C (70 °F), except for a DOT 39 cylinder or a cylinder used for acetylene in solution; or (iii) A cylinder containing a Class 3 or a Class 8 material without pressurization, unless otherwise specified for the hazardous material. (6) A pressure relief device is prohibited on a cylinder filled with a Division 2.3 or 6.1 material in Hazard Zone A. (g) Manifolding cylinders in transportation. (1) Cylinder manifolding is authorized only under conditions prescribed in this paragraph (g). Manifolded cylinders must be supported and held together as a unit by structurally adequate means. Except for Division 2.2 materials, each cylinder must be equipped with an individual shutoff valve that must be tightly closed while in transit. Manifold branch lines must be sufficiently flexible to prevent damage to the valves that otherwise might result from the use of rigid branch lines. Each cylinder must be individually equipped with a pressure relief device as required in paragraph (f) of this section, except that pressure relief devices on manifolded horizontal cylinders that are mounted on a motor vehicle or framework may be selected as to type, location, and quantity according to the lowest marked pressure limit of an individual cylinder in the manifolded unit. The pressure relief devices selected for the manifolded unit must have been tested in accordance with CGA pamphlets S–1.1 and S–7 (IBR, see §171.7 of this subchapter). Pressure relief devices on manifolded horizontal cylinders filled with a compressed gas must be arranged to discharge unobstructed to the open air. In addition, for Division 2.1 (flammable gas) material, the PRDs must be arranged to discharge upward to prevent any escaping gas from contacting personnel or any adjacent cylinders. Valves and pressure relief devices on manifolded cylinders filled with a compressed gas must be protected from damage by framing, a cabinet, or other method. Manifolding is authorized for cylinders containing the following gases: (i) Nonliquefied (permanent) compressed gases authorized by §173.302. (ii) Liquefied compressed gases authorized by §173.304. Each manifolded cylinder containing a liquefied compressed gas must be separately filled and means must be provided to ensure no interchange of cylinder contents can occur during transportation. (iii) Acetylene as authorized by §173.303. (2) For the checking of tare weights or replacing solvent, the cylinder must be removed from the manifold. This requirement is not intended to prohibit filling acetylene cylinders while manifolded. (h) Cylinder valve protection. (1) A cylinder used to transport a hazardous material must meet the requirements specified in this paragraph (h). The following cylinders are not subject to the cylinder valve protection requirements in this paragraph (h): (i) A cylinder containing only a Division 2.2 material without a Division 5.1 subsidiary hazard; (ii) A cylinder containing a Class 8 liquid corrosive only to metal; (iii) A cylinder with a water capacity of 4.8 liters (293 in3 ) or less containing oxygen, compressed; (iv) A cylinder containing oxygen, refrigerated liquid (cryogenic liquid); (v) A Medical E cylinder with a water capacity of 4.9 liters (300 in3 ) or less; (vi) A fire extinguisher; or (vii) A “B” style cylinder with a capacity of 40 ft3 (1.13 m3 ) or an “MC” style cylinder with a capacity of 10 ft3 (0.28m3 ) containing acetylene. (2) For cylinders manufactured before October 1, 2007, a cylinder must have its valves protected by one of the following methods: (i) By equipping the cylinder with securely attached metal caps of sufficient strength to protect valves from damage during transportation; (ii) By boxing or crating the cylinders so as to protect valves from damage during transportation; (iii) By constructing the cylinder so that the valve is recessed into the cylinder or otherwise protected to the extent that it will not be subjected to a blow when the container is dropped onto a flat surface; or (iv) By loading the cylinders in an upright position and securely bracing the cylinders in rail cars or motor vehicles, when loaded by the consignor and unloaded by the consignee. (3) For cylinders manufactured on or after October 1, 2007, each cylinder valve assembly must be of sufficient strength or protected such that no leakage occurs when a cylinder with the valve installed is dropped 1.8 m (6 ft.) or more onto a non-yielding surface, such as concrete or steel, impacting the valve assembly or protection device at an orientation most likely to cause damage. The cylinder valve assembly protection may be provided by any method meeting the performance requirement in this paragraph (h)(3). Examples include: (i) Equipping the cylinder with a securely attached metal cap. (ii) Packaging the cylinder in a box, crate, or other strong outside packaging conforming to the requirements of §173.25. (iii) Constructing the cylinder such that the valve is recessed into the cylinder or otherwise protected. (i) Cylinders mounted on motor vehicles or in frames. Seamless DOT specification cylinders longer than 2 m (6.5 feet) are authorized for transportation only when horizontally mounted on a motor vehicle or in an ISO framework or other framework of equivalent structural integrity. Cylinders may not be transported by rail in container on freight car (COFC) or trailer on flat car (TOFC) service except under conditions approved by the Associate Administrator for Safety, Federal Railroad Administration. The cylinder must be configured as follows: (1) Each cylinder must be fixed at one end of the vehicle or framework with provision for thermal expansion at the opposite end attachment; (2) The valve and pressure relief device protective structure must be sufficiently strong to withstand a force equal to twice the weight of the cylinder and framework assembly with a safety factor of four, based on the ultimate strength of the material used; and (3) The pressure relief device must be arranged to discharge unobstructed to the open air. In addition, for Division 2.1 (flammable gas) material, the pressure relief devices must be arranged to discharge upward to prevent any escaping gas from contacting personnel or any adjacent cylinders. (j) Non-specification cylinders in domestic use. Except as provided in paragraphs (k) and (l) of this section, a filled non-DOT specification cylinder, other than a DOT exemption or special permit cylinder or a cylinder used as a fire extinguisher in conformance with §173.309, may not be offered for transportation or transported to, from, or within the United States. (k) Importation of foreign cylinders for discharge within a single port area. A cylinder manufactured to other than a DOT specification and certified as being in conformance with the transportation regulations of another country may be authorized, upon written request to and approval by the Associate Administrator, for transportation within a single port area, provided— (1) The cylinder is transported in a closed freight container; (2) The cylinder is certified by the importer to provide a level of safety at least equivalent to that required by the regulations in this subchapter for a comparable DOT specification cylinder; and (3) The cylinder is not refilled for export unless in compliance with paragraph (l) of this section. (l) Filling of foreign cylinders for export. A cylinder not manufactured, inspected, tested and marked in accordance with part 178 of this subchapter, or a cylinder manufactured to other than a DOT specification or exemption or special permit, may be filled with a gas in the United States and offered for transportation and transported for export, if the following conditions are met: (1) The cylinder has been requalified and marked with the month and year of requalification in accordance with subpart C of part 180 of this subchapter, or has been requalified as authorized by the Associate Administrator. (2) In addition to other requirements of this subchapter, the maximum filling density, service pressure, and pressure relief device for each cylinder conform to the requirements of this part for the gas involved. (3) The bill of lading or other shipping paper identifies the cylinder and includes the following certification: “This cylinder has (These cylinders have) been qualified, as required, and filled in accordance with the DOT requirements for export.”. (m) Canadian cylinders in domestic use. A Canadian Transport Commission (CTC) specification cylinder manufactured, originally marked and approved in accordance with the CTC regulations and in full conformance with the Canadian Transport of Dangerous Goods (TDG) Regulations (IBR, see §171.7 of this subchapter) is authorized for the transportation of a hazardous material to, from or within the United States under the following conditions: (1) The CTC specification corresponds with a DOT specification and the cylinder markings are the same as those specified in this subchapter except that they were originally marked with the letters “CTC” in place of “DOT”; (2) The cylinder has been requalified under a program authorized by the Canadian TDG regulations or requalified in accordance with the requirements in §180.205 within the prescribed requalification period provided for the corresponding DOT specification; (3) When the regulations authorize a cylinder for a specific hazardous material with a specification marking prefix of “DOT”, a cylinder marked “CTC” which otherwise bears the same markings that would be required of the specified “DOT” cylinder may be used; and (4) Transport of the cylinder and the material it contains is in all other respects in conformance with the requirements of this subchapter (e.g. valve protection, filling requirements, operational requirements, etc.). (n) Metal attachments. Metal attachments to cylinders must have rounded or chamfered corners, or be otherwise protected, so as to prevent the likelihood of causing puncture or damage to other hazardous materials packages. This requirement applies to anything temporarily or permanently attached to the cylinder, such as metal skids. [67 FR 51643, Aug. 8, 2002, as amended at 67 FR 61289, Sept. 30, 2002; 68 FR 24660, May 8, 2003; 68 FR 32680, June 2, 2003; 68 FR 75742, 75745, Dec. 31, 2003; 70 FR 34075, June 13, 2005; 70 FR 73165, Dec. 9, 2005]
Title 49: Transportation
PART 173—SHIPPERS—GENERAL REQUIREMENTS FOR SHIPMENTS AND PACKAGINGS
Subpart G—Gases; Preparation and Packaging
§ 173.301 General requirements for shipment of compressed gases in cylinders and spherical pressure vessels.
