# -17 Closures for openings.

**Citation:** 49 CFR 179.100-17  
**Type / status:** regulation / current  
**Agency:** Pipeline and Hazardous Materials Safety Administration  
**Effective:** 2026-08-18  
**Published:** Not stated

(a) Closures shall be of approved design and made of metal not subject to rapid deterioration by the lading. Plugs, if used, shall be solid, with NPT threads, and shall be of a length which will screw at least six threads inside the face of fitting or tank.

(b) [Reserved]

## Document text

(a) Closures shall be of approved design and made of metal not subject to rapid deterioration by the lading. Plugs, if used, shall be solid, with NPT threads, and shall be of a length which will screw at least six threads inside the face of fitting or tank.

(b) [Reserved]

## Provenance

- Official: Yes
- Source: <https://www.ecfr.gov/on/2026-08-18/title-49/section-179.100-17>
- Source ID: `ecfr`
- SHA-256: `089ba430b470020fa77d14f93699791cf2d8aaf588974fac1fcff50fde5ae0b7`
- Retrieved: 2026-08-20T05:46:20.606Z
- Exported: 2026-08-23T02:39:40.417Z
- Document slug: `49-cfr-179-100-17`

### Source metadata

```json
{
  "cfrTitle": 49,
  "part": "179",
  "section": "179.100-17",
  "subpart": "Subpart C—Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120)",
  "corpusVersion": "2026-08-18",
  "jurisdiction": "US"
}
```