# DOT-3AL cylinders manufactured of 6351-T6 aluminum alloy — How often hazmat cylinders, cargo tanks, IBCs and portable tanks must be retested

For DOT-3AL cylinders manufactured of 6351-T6 aluminum alloy, test or inspection is requalified and inspected for sustained load cracking; condition or service qualifier is used in self-contained underwater breathing apparatus (SCUBA), self-contained breathing apparatus (SCBA), or oxygen service; regulation section is 49 CFR § 180.209, recorded from its source on 2026-08-06.

- **Container specification:** DOT-3AL cylinders manufactured of 6351-T6 aluminum alloy _(verified: appears in the quote below)_
- **Test or inspection:** requalified and inspected for sustained load cracking _(our reading, not quoted from the source)_
- **Condition or service qualifier:** used in self-contained underwater breathing apparatus (SCUBA), self-contained breathing apparatus (SCBA), or oxygen service _(verified: appears in the quote below)_
- **Regulation section:** 49 CFR § 180.209 _(verified: appears in the quote below)_

## What the source says

> DOT-3AL cylinders manufactured of 6351-T6 aluminum alloy. In addition to the periodic requalification and marking described in <https://www.law.cornell.edu/cfr/text/49/180.205> § 180.205 , each cylinder manufactured of aluminum alloy 6351-T6 used in self-contained underwater breathing apparatus (SCUBA), self-contained breathing apparatus (SCBA), or oxygen service must be requalified and inspected for sustained load cracking in accordance with the non-destructive examination method described in the following table.

## 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/).