§173.252 Bulk packaging constructed to ASME Code Section XII.

[Change Notice]

This section authorizes, with certain conditions and limitations, the use of ASME Code Section XII (IBR, see §171.7 of this subchapter) for the construction and continued service of cargo tank motor vehicles, cryogenic portable tanks, and multi-unit tank car tanks (ton tanks). For requirements in parts 178 and 180 of this subchapter not covered by ASME Code Section XII, persons must continue to comply with applicable requirements (e.g., accident damage protection for cargo tank motor vehicles) for the respective packagings in accordance with this subchapter in addition to the Section XII requirements. Table 1 to this section presents the specification packagings authorized for construction using ASME Code Section XII. Conditions and limitations on the use of the ASME Code Section XII for design, construction, qualification and certification, and maintenance are as follows—

(a) All tank types.

(1) Use of ASME Code Section XII for design, construction, qualification, and certification of authorized packaging includes use of ASME Code Section II, Section V, Section VIII Division 1 for parts only, and Division 2 for fatigue analysis only, and Section IX (IBR, see §171.7 of this subchapter);

(2) Continuing qualification, unless excepted, must be in accordance with the NBIC (IBR, see §171.7 of this subchapter), in conjunction with ASME Code Section XII as authorized in part 180 of this subchapter;

(3) Nameplate character markings must be a minimum 4 mm (⁵/₃₂"), markings directly on the tank must be a minimum 8 mm (⁵/₁₆");

(4) Marking must be in accordance with NBIC Supplement 6;

(5) A person performing a certification inspection (i.e., an inspector) must be qualified in accordance with ASME Code Section XII under its general rules for inspection (Article TG-4), and hold either a current National Board of Boiler and Pressure Vessel Inspectors (National Board) commission and endorsement of the ASME tank class (e.g., Class 3 for DOT 406 cargo tanks) for the type of inspection to be performed or, when applicable, a certification (in accordance with the NBIC) from his or her employer. Inspectors of cargo tank motor vehicles, or their employer, must be registered with DOT in accordance with 49 CFR part 107, subpart F; and

(6) A person (e.g., a facility) performing repairs on a cargo tank authorized under this section must hold a current National Board certificate of authorization for the use of the National Board “R” stamp. Persons, or the employer, performing repairs on cargo tanks must also be registered with DOT in accordance with 49 CFR part 107, subpart F.

(b) Cargo tank (motor vehicles). A cargo tank motor vehicle must conform to all applicable requirements of this part, and must meet the standards of ASME Code Section XII, Modal Appendix 1 (for cargo tanks), all Mandatory Appendices and, when opted for, Non Mandatory Appendices, except as follows:

(1) For MC 338 Cargo Tanks, ASME Code Section XII, Modal Appendix 1, Article 4, paragraph 1-4.4(g)(6) does not apply. For evacuated jackets used in flammable liquid service, a minimum jacketed thickness of 2.4 mm (0.0946 in) 12 gauge in the reference metal is permitted.

(2) [Reserved]

(c) Cryogenic portable tanks (UN T75 tanks). Cryogenic portable tanks must conform to all applicable requirements of this part, and must meet ASME Code Section XII, Modal Appendix 3, Article 1, all Mandatory Appendices and, when opted for, Non Mandatory Appendices, except as follows:

(1) An inspector must perform external and internal visual inspection in accordance with NBIC Supplement 6 in addition to ASME Code Section XII, Modal Appendix 3, Article 1, paragraph 3-1.10(b), and Article 1, paragraph 3-1.10(b)(5);

(2) ASME Code Section XII, Modal Appendix 3, Article 1, paragraph 3-1.10(b)(6) does not apply; and

(3) Records must be kept in accordance with the NBIC Supplement 6, as applicable.

(d) Ton tanks. Ton tanks must conform to all applicable requirements of this part and must meet ASME Code Section XII, Modal Appendix 4, Article 1, all Mandatory Appendices and, when opted for, Non Mandatory Appendices, except as follows:

(1) ASME Code Section XII, Modal Appendix 4, Article 1, paragraph 3-1.10 does not apply. Manufacturer-certified fusible plugs, tested, and qualified under the fuse plug manufacturers' written quality control system must be used;

(2) Notwithstanding ASME Code Section XII, Modal Appendix 4, Article 1, paragraph 4-8, non-ASME marked fusible plugs are authorized;

(3) Per ASME Code Section XII, Modal Appendix 4, Article 1, paragraph 4-12(a), an inspector must perform an external and internal visual inspection in accordance with NBIC Supplement 6;

(4) Per ASME Code Section XII, Modal Appendix 4, Article 1, paragraph 4-12(e), records must be kept in accordance with NBIC Supplement 6, as applicable; and

(5) A ton tank that fails a prescribed test or inspection must be repaired in accordance with the NBIC or removed from service.

[91 FR 61158, September 28, 2026]