# DOT 4B, 4BA, 4B240ET or 4BW — How often hazmat cylinders, cargo tanks, IBCs and portable tanks must be retested

For DOT 4B, 4BA, 4B240ET or 4BW, test or inspection is water-jacket, direct expansion or proof pressure test methods; interval is by the end of 12 years after the original test date and at 12-year intervals thereafter; condition or service qualifier is used as a fire extinguisher, with a water capacity of 5.44 kg (12 pounds) or less; regulation section is 49 CFR § 180.209, recorded from its source on 2026-08-06.

- **Container specification:** DOT 4B, 4BA, 4B240ET or 4BW _(verified: appears in the quote below)_
- **Test or inspection:** water-jacket, direct expansion or proof pressure test methods _(our reading, not quoted from the source)_
- **Interval:** by the end of 12 years after the original test date and at 12-year intervals thereafter _(verified: appears in the quote below)_
- **Condition or service qualifier:** used as a fire extinguisher, with a water capacity of 5.44 kg (12 pounds) or less _(verified: appears in the quote below)_
- **Regulation section:** 49 CFR § 180.209 _(verified: appears in the quote below)_

## What the source says

> A DOT 4B, 4BA, 4B240ET or 4BW cylinder used as a fire extinguisher may be tested as follows: (i) For a cylinder with a water capacity of 5.44 kg (12 pounds) or less, by the water-jacket, direct expansion or proof pressure test methods as prescribed in CGA C-1. A requalification must be performed by the end of 12 years after the original test date and at 12-year intervals thereafter.

## Source

- https://www.law.cornell.edu/cfr/text/49/180.209

Last verified: 2026-08-06. Review by: 2027-08-06.
Part of [How often hazmat cylinders, cargo tanks, IBCs and portable tanks must be retested](https://referencesource.org/hazmat-container-retest-intervals/).