(a) General.
(1) Each UN pressure receptacle used for the transportation of hazardous materials must conform to the requirements prescribed in paragraphs (a), (b) and (d) in § 180.205.
(2) No pressure receptacle due for requalification may be filled with a hazardous material and offered for transportation in commerce unless that pressure receptacle has been successfully requalified and marked in accordance with this subpart or requalified and marked by a facility registered by Transport Canada in accordance with the Transport Canada TDG Regulations (IBR, see § 171.7 of this subchapter). A pressure receptacle may be requalified at any time during or before the month and year that the requalification is due. However, a pressure receptacle filled before the requalification becomes due may remain in service until it is emptied. In accordance with the Transport Canada TDG Regulations a CAN marked UN cylinder may be requalified in the United States by a domestic requalifier, provided the requirements in §§ 178.69, 178.70, and 178.71, as applicable, are met.
(3) A pressure receptacle with a specified service life may not be requalified after its authorized service life has expired. A pressure receptacle with a specified service life may not be refilled and offered for transportation after its authorized service life has expired unless approval has been obtained in writing from the Associate Administrator.
(b) Periodic requalification of UN pressure receptacles.
(1) Each pressure receptacle that is successfully requalified in accordance with the requirements specified in this section must be marked in accordance with § 180.213. The requalification results must be recorded in accordance § 180.215.
(2) Each pressure receptacle that fails requalification must be rejected or condemned in accordance with the applicable ISO requalification standard.
(c) Requalification interval. Each UN pressure receptacle that becomes due for periodic requalification must be requalified at the interval specified in the following table before it is filled:
Table 1 - Requalification Intervals of UN Pressure Receptacles
| Interval (years) | UN pressure receptacles/hazardous materials |
|---|---|
| 10 | Pressure receptacles for all hazardous materials except as noted below (also for dissolved acetylene, see paragraph (d)(3) of this section): |
| 5 | Composite pressure receptacles. |
| 5 | Metal hydride storage systems |
| 5 | Pressure receptacles used for: All Division 2.3 materials. UN1013, Carbon dioxide. |
| UN1043, Fertilizer ammoniating solution with free ammonia. UN1051, Hydrogen cyanide, stabilized containing less than 3% water. UN1052, Hydrogen fluoride, anhydrous. UN1745, Bromine pentafluoride. |
|
| UN1746, Bromine trifluoride. UN2073, Ammonia solution. UN2495, Iodine pentafluoride. UN2983, Ethylene Oxide and Propylene oxide mixture, not more than 30% ethylene oxide. |
|
| 5 | Pressure receptacles used for adsorbed gases. |
(d) Requalification procedures. Each UN pressure receptacle must be requalified in conformance with the procedures contained in the following standards, as applicable. Furthermore, when a pressure test is performed on a UN pressure receptacle, the test must be a water jacket volumetric expansion test suitable for the determination of the cylinder expansion or a hydraulic proof pressure test. The test equipment must conform to the accuracy requirements in § 180.205(g). Alternative methods (e.g., acoustic emission) or requalification procedures may be performed if prior approval has been obtained in writing from the Associate Administrator.
(1) Seamless steel: Each seamless steel UN pressure receptacle, including pressure receptacles exceeding 150 L capacity installed in MEGCs or in other service, must be requalified in accordance with ISO 6406:2005(E) (IBR, see § 171.7 of this subchapter). However, UN cylinders with a tensile strength greater than or equal to 950 MPa must be requalified by ultrasonic examination in accordance with ISO 6406:2005(E). For seamless steel cylinders and tubes, the internal inspection and hydraulic pressure test may be replaced by a procedure conforming to ISO 16148:2016(E) (IBR, see § 171.1).
(2) Seamless UN aluminum: Each seamless aluminum UN pressure receptacle must be requalified in accordance with ISO 10461 (IBR, see § 171.7 of this subchapter).
(3) Dissolved acetylene UN cylinders: Each dissolved acetylene cylinder must be requalified in accordance with ISO 10462:2013(E) (IBR, see § 171.7 of this subchapter). Until December 31, 2018 requalification may be done in accordance with ISO 10462(E) (IBR, see § 171.7 of this subchapter). The porous mass and the shell must be requalified no sooner than 3 years, 6 months, from the date of manufacture. Thereafter, subsequent requalifications of the porous mass and shell must be performed at least once every ten years.
(4) Composite UN cylinders: Each composite cylinder must be inspected and tested in accordance with ISO 11623:2015(E) (IBR, see § 171.7 of this subchapter). Until December 31, 2020, ISO 11623:2002(E) (IBR, see § 171.7 of this subchapter) may be used.
(5) UN cylinders for adsorbed gases: Each UN cylinder for adsorbed gases must be inspected and tested in accordance with § 173.302c and ISO 11513:2011 (IBR, see § 171.7 of this subchapter).
(6) Valves: Inspection and maintenance of cylinder valves must be carried out in accordance with ISO 22434:2006 Transportable gas cylinders - Inspection and maintenance of cylinder valves (IBR, see § 171.7 of this subchapter).
[71 FR 33894, June 12, 2006, as amended at 71 FR 54397, Sept. 14, 2006; 76 FR 3389, Jan. 19, 2011; 80 FR 1168, Jan. 8, 2015; 82 FR 15897, Mar. 30, 2017; 85 FR 27901, May 11, 2020; 85 FR 85434, Dec. 28, 2020]