# -3 Expansion domes.

**Citation:** 49 CFR 178.255-3  
**Type / status:** regulation / current  
**Agency:** Pipeline and Hazardous Materials Safety Administration  
**Effective:** 2026-08-18  
**Published:** Not stated

(a) Expansion domes, if applied, must have a minimum capacity of one percent of the combined capacity of the tank and dome.

(b) [Reserved]

## Document text

(a) Expansion domes, if applied, must have a minimum capacity of one percent of the combined capacity of the tank and dome.

(b) [Reserved]

## Provenance

- Official: Yes
- Source: <https://www.ecfr.gov/on/2026-08-18/title-49/section-178.255-3>
- Source ID: `ecfr`
- SHA-256: `1ee92e6a081a87c1e34cfd0832fb418e2f292ec7119eadc48c5388fa42325901`
- Retrieved: 2026-08-20T05:46:20.151Z
- Exported: 2026-08-24T06:33:32.349Z
- Document slug: `49-cfr-178-255-3`

### Source metadata

```json
{
  "cfrTitle": 49,
  "part": "178",
  "section": "178.255-3",
  "subpart": "Subpart H—Specifications for Portable Tanks",
  "corpusVersion": "2026-08-18",
  "jurisdiction": "US"
}
```