DOT 3A, 3AA, or 3AL · water-jacket or direct expansion method · used as a fire extinguisher
For DOT 3A, 3AA, or 3AL, test or inspection is water-jacket or direct expansion method; condition or service qualifier is used as a fire extinguisher; interval is 12 years after the original test date and at 12-year intervals thereafter; regulation section is 49 CFR § 180.209, recorded from its source on 2026-08-06; source re-checked 2026-09-30.
- Container specification
- DOT 3A, 3AA, or 3AL verified
- Test or inspection
- water-jacket or direct expansion method our reading
- Interval
- 12 years after the original test date and at 12-year intervals thereafter verified
- Condition or service qualifier
- used as a fire extinguisher
- Regulation section
- 49 CFR § 180.209
Values marked our reading are our classification of what the source says — the source does not print them in those words. The quote below is the evidence for each one; judge it yourself.
What the source says
A DOT 3A, 3AA, or 3AL cylinder must be requalified by: (i) The water-jacket or direct expansion method. A requalification must be performed 12 years after the original test date and at 12-year intervals thereafter.
— law.cornell.edu, retrieved 2026-08-06
Source
- law.cornell.eduhttps://www.law.cornell.edu/cfr/text/49/180.209