# -22 Closure for openings.

**Citation:** 49 CFR 179.220-22  
**Type / status:** regulation / current  
**Agency:** Pipeline and Hazardous Materials Safety Administration  
**Effective:** 2026-08-18  
**Published:** Not stated

(a) All plugs must be solid, with NPT threads, and must be of a length which will screw at least six threads inside the face of fitting or tank. Plugs, when inserted from the outside of the outer shell tank heads, must have the letter “S” at least three-eighths inch in size stamped with steel stamp 

## Document text

(a) All plugs must be solid, with NPT threads, and must be of a length which will screw at least six threads inside the face of fitting or tank. Plugs, when inserted from the outside of the outer shell tank heads, must have the letter “S” at least three-eighths inch in size stamped with steel stamp or cast on the outside surface to indicate the plug is solid.

(b) Openings in the outer shell used during construction for installation must be closed in an approved manner.

[Amdt. 179-9, 36 FR 21343, Nov. 6, 1971]

## Provenance

- Official: Yes
- Source: <https://www.ecfr.gov/on/2026-08-18/title-49/section-179.220-22>
- Source ID: `ecfr`
- SHA-256: `9d800fc207698f4073d4b8e55070475b001e7b8a3e492bba780f80ebd57f0a18`
- Retrieved: 2026-08-20T05:46:20.606Z
- Exported: 2026-08-24T09:41:14.616Z
- Document slug: `49-cfr-179-220-22`

### Source metadata

```json
{
  "cfrTitle": 49,
  "part": "179",
  "section": "179.220-22",
  "subpart": "Subpart D—Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW, 115AW, and 117AW)",
  "corpusVersion": "2026-08-18",
  "jurisdiction": "US"
}
```