How often hazmat cylinders, cargo tanks, IBCs and portable tanks must be retested
Mandatory requalification, retest and inspection intervals for pressure containers under 49 CFR Part 180, with the qualifier that decides which interval applies. Each record is one container specification under one test type, stating the interval in years and the condition attached to it. Covers cylinders (49 CFR 180.209), cargo tanks (180.407), intermediate bulk containers (180.352) and portable tanks (180.605). Answers 'how often does a scuba tank need hydro testing', 'DOT 3AL requalification 5 years or 12', 'IBC tote retest interval 2.5 years', 'MC-331 propane cargo tank internal visual inspection frequency', and 'when does a DOT 3AA cylinder qualify for the 10 year star'. The interval is a property of the specification, the service and the configuration together, not of the container alone, and the exceptions are where the answers go wrong: DOT 3AL is 5 or 12 years depending on service, and an MC-331 under 3,500 gallons in dedicated propane service built from non-quenched-and-tempered SA-612 gets 10 years where every other cargo tank gets 5. Past the due date the container may not be filled and offered for transportation.
Records41
Sources1
Verified2026-08-06
Review by2027-08-06
LicenceFacts extracted from the US Code of Federal Regulations, a US government work not subject to copyright. Text is read via law.cornell.edu because eCFR blocks our fetcher; the fact is the regulation's, not Cornell's, and each record quotes a short verbatim span and links back to the section.
The data
| Container specification | Test or inspection | Interval | Condition or service qualifier | Regulation section | Minimum test pressure |
|---|---|---|---|---|---|
| DOT 4B, 4BA, 4B240ET or 4BW | proof-pressure test | by the end of 12 years after the original test date and at seven (7) year intervals | a water capacity over 5.44 kg (12 pounds) | 49 CFR § 180.209 | |
| DOT 4B, 4BA, 4B240ET or 4BW | water-jacket or direct expansion test | by the end of 12 years after the original test date and at 12-year intervals theafter | a water capacity over 5.44 kg (12 pounds) | 49 CFR § 180.209 | |
| DOT 4BW | External visual inspection | at five-year intervals after the first inspection | Alkali metal alloys, liquid, n.o.s., Alkali metal dispersions or Alkaline earth metal dispersions, Potassium, Potassium Sodium alloys and Sodium that are commercially free of corroding components | 49 CFR § 180.209 | |
| DOT 3A, DOT 3AA, DOT 3A480X, DOT 4AA480 | External visual inspection | at five-year intervals after the first inspection | Anhydrous ammonia of at least 99.95% purity | 49 CFR § 180.209 | |
| DOT 3A, DOT 3AA, DOT 3B, DOT 4B, DOT 4BA, DOT 4BW | External visual inspection | at five-year intervals after the first inspection | Anhydrous mono, di, trimethylamines that are commercially free from corroding components | 49 CFR § 180.209 | |
| DOT 3A, DOT 3AA, DOT 3A480X, DOT 3B, DOT 4B, DOT 4BA, DOT 4BW | External visual inspection | at five-year intervals after the first inspection | Butadiene, inhibited, that is commercially free from corroding components | 49 CFR § 180.209 | |
| DOT 3A, DOT 3AA, DOT 3A480X, DOT 4B, DOT 4BA, DOT 4BW, DOT 4E | External visual inspection | at five-year intervals after the first inspection | Chlorinated hydrocarbons and mixtures thereof that are commercially free from corroding components | 49 CFR § 180.209 | |
| DOT 3A, DOT 3AA, DOT 3A480X, DOT 3B. DOT 4AA480, DOT 4B, DOT 4BA, DOT 4BW | External visual inspection | at five-year intervals after the first inspection | Cyclopropane that is commercially free from corroding components | 49 CFR § 180.209 | |
| DOT-3AL Cylinders Made of Aluminum Alloy 6351-T6 | Eddy current examination combined with visual inspection | 5 | 49 CFR § 180.209 | ||
| DOT 4B240, DOT 4BW240 | External visual inspection | at five-year intervals after the first inspection | Ethyleneimine, stabilized | 49 CFR § 180.209 | |
| DOT 3A, DOT 3AA, DOT 3A480X, DOT 4B, DOT 4BA, DOT 4BW, DOT 4E | External visual inspection | at five-year intervals after the first inspection | Fluorinated hydrocarbons and mixtures thereof that are commercially free from corroding components | 49 CFR § 180.209 | |
| DOT 3A, DOT 3AA, DOT 3A480X, DOT 3B, DOT 4B, DOT 4BA, DOT 4BW, DOT 4E | External visual inspection | at five-year intervals after the first inspection | Liquefied hydrocarbon gas that is commercially free of corroding components | 49 CFR § 180.209 | |
| DOT 3A, DOT 3AA, DOT 3A480X, DOT 3B, DOT 4B, DOT 4BA, DOT 4BW, DOT 4E | External visual inspection | at five-year intervals after the first inspection | Liquefied petroleum gas that meets the detail requirements limits in Table 1 of ASTM 1835, Standard Specification for Liquefied Petroleum (LP) Gases | 49 CFR § 180.209 | |
| DOT 3A, DOT 3AA, DOT 3B, DOT 4B, DOT 4BA, DOT 4BW, DOT 4E | External visual inspection | at five-year intervals after the first inspection | Methylacetylene-propadiene, stabilized, that is commercially free from corroding components | 49 CFR § 180.209 | |
| DOT-8 series | Porous filler requalification | 5 to 20 years | On or after January 1, 1991 | 49 CFR § 180.209 | |
| DOT-8 series | Shell (visual inspection) requalification | 10 years | On or after January 1, 1991 | 49 CFR § 180.209 | |
| 3 | Periodic requalification | 5. | 49 CFR § 180.209 | 3000 psig | |
| 3A, 3AA | Periodic requalification | 5, 10, or 12 | 49 CFR § 180.209 | 5/3 times service pressure, except non-corrosive service | |
| 3AL | Periodic requalification | 5 or 12 | 49 CFR § 180.209 | 5/3 times service pressure | |
| 3AX, 3AAX | Periodic requalification | 5. | 49 CFR § 180.209 | 5/3 times service pressure | |
| 3B, 3BN | Periodic requalification | 5 or 10 | 49 CFR § 180.209 | 2 times service pressure | |
| 3E | Periodic requalification | 49 CFR § 180.209 | Test not required | ||
| 3HT | Periodic requalification | 3 | 49 CFR § 180.209 | 5/3 times service pressure | |
| 3T | Periodic requalification | 5. | 49 CFR § 180.209 | 5/3 times service pressure or UE | |
| 4AA480 | Periodic requalification | 5 or 10 | 49 CFR § 180.209 | 2 times service pressure | |
| 4B, 4BA, 4BW, 4B-240ET | Periodic requalification | 5, 7, 10, or 12 | 49 CFR § 180.209 | 2 times service pressure, except non-corrosive service | |
| 4D, 4DA, 4DS | Periodic requalification | 5. | 49 CFR § 180.209 | 2 times service pressure | |
| 4E | Periodic requalification | 5, 10, or 12 | 49 CFR § 180.209 | 2 times service pressure, except non-corrosive service | |
| 4L | Periodic requalification | 49 CFR § 180.209 | Test not required | ||
| 8, 8AL | Periodic requalification | 10 or 20 | 49 CFR § 180.209 | ||
| Exemption or special permit cylinder | Periodic requalification | See current exemption or special permit | 49 CFR § 180.209 | See current exemption or special permit | |
| Foreign cylinder | Periodic requalification | 5 | 49 CFR § 180.209 | As marked on cylinder, but not less than 5/3 of any service or working pressure marking | |
| DOT 3A, DOT 3AA, DOT 3B, DOT 4B, DOT 4BA, DOT 4BW, DOT 4E | External visual inspection | at five-year intervals after the first inspection | Propylene that is commercially free from corroding components | 49 CFR § 180.209 | |
| DOT Specifications 4B, 4BA, 4BW, or 4E | volumetric expansion testing | every 12 years instead of every 5 years | protected externally by a suitable corrosion-resistant coating and used exclusively for non-corrosive gas that is commercially free from corroding components | 49 CFR § 180.209 | |
| DOT 3A or 3AA | Periodic requalification | every ten years instead of every five years | removed from any cluster, bank, group, rack, or vehicle each time it is filled | 49 CFR § 180.209 | |
| DOT 3A, 3AA, or 3AL | water-jacket or direct expansion method | 12 years after the original test date and at 12-year intervals thereafter | used as a fire extinguisher | 49 CFR § 180.209 | |
| DOT 4B, 4BA, 4B240ET or 4BW | water-jacket, direct expansion or proof pressure test methods | by the end of 12 years after the original test date and at 12-year intervals thereafter | used as a fire extinguisher, with a water capacity of 5.44 kg (12 pounds) or less | 49 CFR § 180.209 | |
| DOT 3A, 3A480X, or 4AA480 | Periodic requalification | every 10 years instead of every five years | used exclusively for anhydrous ammonia, commercially free from corroding components, and protected externally by a suitable corrosion-resistant coating (such as paint) | 49 CFR § 180.209 | |
| DOT 3A, 3AA, 3B, 4BA, or 4BW | Periodic requalification | every 10 years instead of every five years | used exclusively for methyl bromide | 49 CFR § 180.209 | |
| a specification listed in the table in this paragraph (g) | complete external visual inspection | at five-year intervals after the first inspection | used exclusively in the service indicated | 49 CFR § 180.209 | |
| DOT-3AL cylinders manufactured of 6351-T6 aluminum alloy | requalified and inspected for sustained load cracking | used in self-contained underwater breathing apparatus (SCUBA), self-contained breathing apparatus (SCBA), or oxygen service | 49 CFR § 180.209 |
Where this came from
Every record above links the page it was taken from and quotes the sentence that states it. These are the 1 source this dataset was assembled from.
- law.cornell.eduhttps://www.law.cornell.edu/cfr/text/49/180.209
Machine-readable
- data.jsonThe whole dataset — every record with its source URL and source quote.
- Open Knowledge Format bundleOne JSON object per line — every record's frontmatter and quoted span exactly as it is held here, in one fetch.
- How this is made and checkedWhat "verified against source" does and does not mean.