# Metal Hydride Storage Systems.

**Citation:** 49 CFR 173.311  
**Type / status:** regulation / current  
**Agency:** Pipeline and Hazardous Materials Safety Administration  
**Effective:** 2026-08-18  
**Published:** Not stated

The following packing instruction is applicable to transportable UN Metal hydride storage systems (UN3468) with pressure receptacles not exceeding 150 liters (40 gallons) in water capacity, and having a maximum developed pressure not exceeding 25 MPa. UN Metal hydride storage systems must be designe

## Document text

The following packing instruction is applicable to transportable UN Metal hydride storage systems (UN3468) with pressure receptacles not exceeding 150 liters (40 gallons) in water capacity, and having a maximum developed pressure not exceeding 25 MPa. UN Metal hydride storage systems must be designed, constructed, initially inspected, and tested in accordance with ISO 16111:2018 (IBR, see § 171.7 of this subchapter), consistent with § 178.71(m) of this subchapter. Until December 31, 2026, UN Metal hydride storage systems may instead conform to ISO 16111:2008(E) (IBR, see § 171.7 of this subchapter). Steel pressure receptacles or composite pressure receptacles with steel liners must be marked in accordance with § 173.301b(f), which specifies that a steel UN pressure receptacle displaying an “H” mark must be used for hydrogen-bearing gases or other gases that may cause hydrogen embrittlement. Requalification intervals must be no more than every five years, as specified in § 180.207 of this subchapter, in accordance with the requalification procedures prescribed in ISO 16111:2018 or ISO 16111:2008.

[89 FR 25487, Apr. 10, 2024]

## Provenance

- Official: Yes
- Source: <https://www.ecfr.gov/on/2026-08-18/title-49/section-173.311>
- Source ID: `ecfr`
- SHA-256: `a299c1bac0f6cc2b6419e2c7c7c640a4a38a32cd828ae1d11fe19eabe9d50980`
- Retrieved: 2026-08-20T05:46:04.092Z
- Exported: 2026-08-22T02:57:30.401Z
- Document slug: `49-cfr-173-311`

### Source metadata

```json
{
  "cfrTitle": 49,
  "part": "173",
  "section": "173.311",
  "subpart": "Subpart G—Gases; Preparation and Packaging",
  "corpusVersion": "2026-08-18",
  "jurisdiction": "US"
}
```