# ISO 9809 Design, construction and testing of seamless steel cylinders

ISO 9809 is the four-part ISO series on the design, construction and testing of refillable seamless steel gas cylinders and tubes; the editions in force are ISO 9809-1, 9809-2 and 9809-3:2019, which ISO marked for revision on 27 August 2026, and ISO 9809-4:2026, which replaced the 2021 edition in February 2026.

## What the series covers

Each part specifies minimum requirements for the material, design, construction and workmanship, manufacturing processes, examination and testing at the time of manufacture of refillable seamless steel gas cylinders for compressed, liquefied and dissolved gases. Parts 1 to 3 also cover tubes, with water capacities up to and including 450 l; the parts differ by type of steel and tensile strength.

| Part | Scope | Edition in force | Status on 22 October 2026 |
|---|---|---|---|
| ISO 9809-1 | Quenched and tempered steel cylinders and tubes, maximum actual tensile strength below 1 100 MPa | ISO 9809-1:2019 (edition 3, 56 pages) | Confirmed 5 February 2025; marked for revision 27 August 2026 |
| ISO 9809-2 | Quenched and tempered steel cylinders and tubes, actual tensile strength of 1 100 MPa or more, within stated limits | ISO 9809-2:2019 (edition 3, 57 pages) | Confirmed 5 February 2025; marked for revision 27 August 2026 |
| ISO 9809-3 | Normalized, or normalized and tempered, steel cylinders and tubes | ISO 9809-3:2019 (edition 3, 54 pages) | Confirmed 5 February 2025; marked for revision 27 August 2026 |
| ISO 9809-4 | Stainless steel cylinders, maximum actual tensile strength below 1 100 MPa, water capacity up to 150 l | ISO 9809-4:2026 (edition 3, 53 pages) | Published February 2026; the 2021 edition was withdrawn on 23 February 2026 |

## Edition history and revisions

- ISO published Parts 1, 2 and 3 in August 2019, replacing the 2010 editions. On 27 August 2026 ISO registered new projects, ISO/AWI 9809-1, 9809-2 and 9809-3, that will replace the 2019 editions, so check iso.org before citing an edition.
- Part 4 applies to stainless steel cylinders up to and including 150 l; ISO notes that cylinders between 150 l and 450 l can be manufactured in full conformance with it if so desired.
- Part 2 does not apply beyond stated limits of tensile strength, diameter and wall thickness, because beyond these limits additional requirements can apply.

## Related standards

- ISO lists a separate standard for the design, construction and testing of refillable seamless aluminium alloy gas cylinders.
- The marking and colours that identify the content of medical gas cylinders are the subject of [ISO 32](https://library.ultracontrolo.com/standards/iso-32-cylinder-colours/).

### Which part of ISO 9809 applies to stainless steel cylinders?

ISO 9809-4, whose edition in force is ISO 9809-4:2026, for cylinders up to 150 l with a maximum actual tensile strength below 1 100 MPa.

### Is ISO 9809-1:2019 still current?

Yes. ISO confirmed it on 5 February 2025; on 27 August 2026 ISO marked it for revision and registered a new project, ISO/AWI 9809-1, to replace it.

## Sources

- [ISO 9809-1:2019 (iso.org)](https://www.iso.org/standard/70377.html)
- [ISO 9809-2:2019 (iso.org)](https://www.iso.org/standard/70378.html)
- [ISO 9809-3:2019 (iso.org)](https://www.iso.org/standard/70379.html)
- [ISO 9809-4:2026 (iso.org)](https://www.iso.org/standard/87936.html)
- [ISO 9809-4:2021, withdrawn (iso.org)](https://www.iso.org/standard/76548.html)
- [ISO/AWI 9809-1 (iso.org)](https://www.iso.org/standard/95223.html)
- [ISO/AWI 9809-2 (iso.org)](https://www.iso.org/standard/95224.html)
- [ISO/AWI 9809-3 (iso.org)](https://www.iso.org/standard/95225.html)
- [ISO, ICS 23.020.35 Gas cylinders (list of standards)](https://www.iso.org/ics/23.020.35/x/)
- [ISO 32:1977, Gas cylinders for medical use, marking (iso.org)](https://www.iso.org/standard/3659.html)

Reviewed: 2026-10-22. Ultra Controlo engineering. https://library.ultracontrolo.com/standards/iso-9809/