# Metal Hydride Storage Systems.

- **operation:** document
- **citation:** 49 CFR 173.311
- **title:** Metal Hydride Storage Systems.
- **source type:** regulation
- **agency:** Pipeline and Hazardous Materials Safety Administration
- **status:** current
- **official:** true
- **published on:** Not available
- **effective on:** 2026-08-18
- **summary:** 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
- **machine formats:** - **json:** https://regulus.evalyn.ai/document/49-cfr-173-311.json
- **markdown:** https://regulus.evalyn.ai/document/49-cfr-173-311.md
- **app url:** https://regulus.evalyn.ai/document/49-cfr-173-311
- **source url:** https://www.ecfr.gov/on/2026-08-18/title-49/section-173.311
**body:**

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]
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