# -16 Access to inner tank.

**Citation:** 49 CFR 179.400-16  
**Type / status:** regulation / current  
**Agency:** Pipeline and Hazardous Materials Safety Administration  
**Effective:** 2026-08-18  
**Published:** Not stated

(a) The inner tank must be provided with a means of access having a minimum inside diameter of 16 inches. Reinforcement of the access opening must be made of the same material used in the inner tank. The access closure must be of an approved material and design.

(b) If a welded closure is used, it 

## Document text

(a) The inner tank must be provided with a means of access having a minimum inside diameter of 16 inches. Reinforcement of the access opening must be made of the same material used in the inner tank. The access closure must be of an approved material and design.

(b) If a welded closure is used, it must be designed to allow it to be reopened by grinding or chipping and to be closed again by rewelding, preferably without a need for new parts. A cutting torch may not be used.

## Provenance

- Official: Yes
- Source: <https://www.ecfr.gov/on/2026-08-18/title-49/section-179.400-16>
- Source ID: `ecfr`
- SHA-256: `5158814180f79468bd7dd60b2afd366618cbb43193036d56531dd1d45d731792`
- Retrieved: 2026-08-20T05:46:20.606Z
- Exported: 2026-08-22T20:38:21.206Z
- Document slug: `49-cfr-179-400-16`

### Source metadata

```json
{
  "cfrTitle": 49,
  "part": "179",
  "section": "179.400-16",
  "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"
}
```