# -11 Welding.

**Citation:** 49 CFR 179.400-11  
**Type / status:** regulation / current  
**Agency:** Pipeline and Hazardous Materials Safety Administration  
**Effective:** 2026-08-18  
**Published:** Not stated

(a) Except for closure of openings and a maximum of two circumferential closing joints in the cylindrical portion of the outer jacket, each joint of an inner tank and the outer jacket must be a fusion double welded butt joint.

(b) The closure for openings and the circumferential closing joints in t

## Document text

(a) Except for closure of openings and a maximum of two circumferential closing joints in the cylindrical portion of the outer jacket, each joint of an inner tank and the outer jacket must be a fusion double welded butt joint.

(b) The closure for openings and the circumferential closing joints in the cylindrical portion of the outer jacket, including head to shell joints, may be a single welded butt joint using a backing strip on the inside of the joint.

(c) Each joint must be welded in accordance with the requirements of AAR Specifications for Tank Cars, appendix W (IBR, see § 171.7 of this subchapter).

(d) Each welding procedure, welder, and fabricator must be approved.

[Amdt. 179-32, 48 FR 27708, June 16, 1983, as amended at 68 FR 75763, Dec. 31, 2003]

## Provenance

- Official: Yes
- Source: <https://www.ecfr.gov/on/2026-08-18/title-49/section-179.400-11>
- Source ID: `ecfr`
- SHA-256: `4c71ad0fe843529f85fc84fb07453c5b3030919b3276ab74146b918efec73e5f`
- Retrieved: 2026-08-20T05:46:20.606Z
- Exported: 2026-08-24T17:06:45.776Z
- Document slug: `49-cfr-179-400-11`

### Source metadata

```json
{
  "cfrTitle": 49,
  "part": "179",
  "section": "179.400-11",
  "subpart": "Subpart F—Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A)",
  "corpusVersion": "2026-08-18",
  "jurisdiction": "US"
}
```