# -4 Safety relief devices and pressure regulators.

**Citation:** 49 CFR 179.103-4  
**Type / status:** regulation / current  
**Agency:** Pipeline and Hazardous Materials Safety Administration  
**Effective:** 2026-08-18  
**Published:** Not stated

(a) Safety relief devices and pressure regulators must be located on top of the tank near the center of the car on a nozzle, mounting plate or recess in the shell. Through or stud bolts, if used, must not enter the tank.

(b) Metal guard of approved design must be provided to protect safety relief d

## Document text

(a) Safety relief devices and pressure regulators must be located on top of the tank near the center of the car on a nozzle, mounting plate or recess in the shell. Through or stud bolts, if used, must not enter the tank.

(b) Metal guard of approved design must be provided to protect safety relief devices and pressure regulators from damage.

[Amdt. 179-10, 36 FR 21348, Nov. 6, 1971]

## Provenance

- Official: Yes
- Source: <https://www.ecfr.gov/on/2026-08-18/title-49/section-179.103-4>
- Source ID: `ecfr`
- SHA-256: `77f64d8a54bc3d1809c6a7042e3bb03669ffbc614915ff919bd3f806863dfb6b`
- Retrieved: 2026-08-20T05:46:20.606Z
- Exported: 2026-08-22T20:33:59.661Z
- Document slug: `49-cfr-179-103-4`

### Source metadata

```json
{
  "cfrTitle": 49,
  "part": "179",
  "section": "179.103-4",
  "subpart": "Subpart C—Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120)",
  "corpusVersion": "2026-08-18",
  "jurisdiction": "US"
}
```