The code on UN-approved steel fuel cans, character by character, with its limits and tests.
UN 3A1 is the packaging code for a steel jerrican with a closed head: 3 for jerrican, A for steel, 1 for a head that does not come off. It holds at most 60 litres and 120 kg net, and UN-approved steel fuel cans usually carry it.
Decode a full 3A1 mark Ask for 3A1 containers
| Character | Meaning |
|---|---|
3 | Jerrican: rectangular or polygonal cross-section |
A | Steel, of any type and surface treatment |
1 | Non-removable head, with openings no wider than 7 cm |
| Maximum capacity | 60 litres (6.1.4.4.5) |
|---|---|
| Maximum net mass | 120 kg |
As a single packaging for liquids, packing instruction P001 sets the working limits by packing group. For a 3A1 that is 60 litres in every packing group, and 120 kg for solids.
Liquids or solids, in any packing group the mark allows. Body seams must be welded on a can that holds more than 40 litres of liquid. Where the steel does not suit the contents, the can needs an internal coating, and closures need gaskets unless they seal by design (6.1.4.4).
| Test | What the design has to survive | Paragraph |
|---|---|---|
| Drop | Filled to at least 98 per cent and dropped on its weakest points: from 1.8 m for packing group I, 1.2 m for II and 0.8 m for III. Tested with water, a liquid denser than 1.2 drops from its relative density times 1.5, 1.0 or 0.67 m. | 6.1.5.3 |
| Leakproofness | Held under water for five minutes at an air pressure of 30 kPa for packing group I or 20 kPa for II and III. Every container made for liquids passes the same test before its first use. | 6.1.5.4, 6.1.1.3 |
| Internal pressure | Held for five minutes at the hydraulic pressure the mark states, at least 250 kPa for packing group I. | 6.1.5.5 |
| Stacking | Carries the weight of a 3 m stack of identical full packages for 24 hours without leaking or losing strength. | 6.1.5.6 |
A design marked S for solids needs the drop and stacking tests only. The leakproofness and pressure tests belong to designs for liquids.
No period-of-use limit applies to steel or aluminium drums and jerricans: the five-year rule in 4.1.1.15 covers plastics only. A container made for liquids passes a leakproofness test before its first use.
3A2 is the same steel jerrican with a removable head, or any opening wider than 7 cm. It carries solids and packing group II and III liquids, and packing group I liquids only when they are viscous. 3B1 is the aluminium version of 3A1, with every seam welded. 1A1 is a cylindrical steel drum of up to 450 litres.
UN 3A1/X1.2/250/25/GB/6631A closed-head steel jerrican, approved for packing groups I, II and III, for liquids up to relative density 1.2, pressure-tested at 250 kPa, made in 2025, design approved in the United Kingdom.
| Part | On the mark | What it means |
|---|---|---|
| Packaging code | 3A1 | Closed-head steel jerrican (3 = jerrican, A = steel, 1 = non-removable head) |
| Performance level | X | Approved for packing groups I, II and III (high, medium and low danger) |
| Relative density | 1.2 | Tested for liquids up to a relative density of 1.2 (water is 1.0) |
| Test pressure | 250 | Passed a hydraulic pressure test at 250 kPa |
| Year of manufacture | 25 | Made in 2025 |
| Approving country | GB | Design approved in the United Kingdom |
| Manufacturer or approval number | 6631 | Identifies the manufacturer or the approved design, as set by the approving authority |
Another 3A1 mark, decoded: UN 3A1/Y1.2/100/25/NL/VL828
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It means the can is a steel jerrican with a closed head that passed the UN tests for dangerous goods packaging. 3 is jerrican, A is steel and 1 is a head that does not come off.
No period-of-use limit applies to steel jerricans. The five-year limit covers plastic drums, jerricans and IBCs only.
The standards and regulations this page relies on, at their issuing body. Where a market rule is named here, check the current revision before you specify against it.
Checked against the UN Model Regulations, Rev. 24, and ADR 2025 on 5 October 2026. Decode any other mark with our UN packaging code decoder.
Send what goes in them, the size and where they ship. We reply with the design certified to this code, the plant named on its certificate, and a price.