# ISO 21969:2009: high-pressure flexible connections for medical gases

ISO 21969:2009 is the ISO standard for high-pressure flexible connections that link medical gas cylinders or cylinder bundles, at nominal filling pressures up to 25 000 kPa at 15 °C, to pipeline manifolds or to medical equipment; ISO lists edition 2 (November 2009) as current, last reviewed and confirmed in 2022.

## Scope

According to the ISO abstract, the standard applies to high-pressure flexible connections intended to be connected to cylinders or cylinder bundles with nominal filling pressures up to 25 000 kPa at 15 °C. It covers two uses: connecting cylinders or bundles to manifolds within the sources of supply of medical gas pipeline systems complying with ISO 7396-1, and connecting a cylinder to an inlet port of medical equipment, such as an anaesthetic workstation or lung ventilator, fitted with an integral pressure regulator complying with ISO 10524-1.

The gases listed are oxygen, nitrous oxide, air for breathing, helium, carbon dioxide, xenon, mixtures of these gases, air and nitrogen for driving surgical tools, and oxygen-enriched air.

## Edition and status

- Edition 2, published in November 2009, 13 pages, prepared by ISO/TC 121/SC 6. It replaced ISO 21969:2005, which ISO lists as withdrawn.
- On 23 October 2026 the ISO page showed stage 90.93 (International Standard confirmed): the publication was last reviewed and confirmed in 2022, so this version remains current. ISO reviews its standards every 5 years.
- NHS England's HTM 02-01 (2026) cites it as BS EN ISO 21969:2009.

## How hospital guidance uses it

- HTM 02-01 Part B (2026), 4.18, describes the standard as applying to the flexible connections used to connect medical gas cylinders to manifolds, and says it states that non-metallic hoses should not be used, in addition to requirements for gas-specific connections and ignition and other safety-related items.
- SHTM 02-01 Part A (NHS Scotland, Version 2, August 2026) states that cylinder manifold tailpipes manufactured to ISO 21969 will provide a flow of 83 litres/min when the cylinders are nominally empty (20 bar(g)) (5.131), and that ISO 21969 specifies that the flexible hose for cylinder packs should be rated at 830 litres/min gas flow when the pack drops to nominally empty contents (5.136).
- The 2020 WHO interim specification for PSA oxygen plants, which WHO's December 2024 specifications supersede, listed ISO 21969 among its product performance standards.

## Tailpipes in manifold design and maintenance

Under HTM 02-01 Part A (2026), 5.33, manifold headers should incorporate a replaceable check valve to prevent discharge of a complete cylinder bank in the event of tailpipe rupture. The maintenance tasks for automatic manifolds in Part B (11.170) include isolating one cylinder in turn and disconnecting the tailpipe to check its non-return valve: a minor weep is permissible and likely, but an obvious major leak denotes failure of the valve. The tasks for manual emergency reserve manifolds (11.168) include the same check.

## Related standards

[ISO 7396-1](https://library.ultracontrolo.com/standards/iso-7396-1/) covers the pipeline system and its sources of supply, and [ISO 10524](https://library.ultracontrolo.com/standards/iso-10524/) covers pressure regulators. Low-pressure hose assemblies are a separate standard, [ISO 5359](https://library.ultracontrolo.com/standards/iso-5359/), which HTM 02-01 Part B lists on its own (4.17).

### Does ISO 21969 cover low-pressure hoses at the bedside?

No. Its abstract covers high-pressure connections to cylinders or cylinder bundles; low-pressure hose assemblies are covered by ISO 5359, which HTM 02-01 (2026) lists separately.

### Is ISO 21969:2009 still current?

Yes. On 23 October 2026 ISO listed edition 2 (2009) at stage 90.93, last reviewed and confirmed in 2022.

## Sources

- [ISO 21969:2009, iso.org (read in a browser on 23 October 2026)](https://www.iso.org/standard/52967.html)
- [NHS England, HTM 02-01 Part B (2026), paragraphs 4.17, 4.18, 11.168 and 11.170](https://www.england.nhs.uk/wp-content/uploads/2016/05/health-technical-memorandum-02-01-medical-gas-pipeline-systems-part-b-operational-management-aug-26.pdf)
- [NHS England, HTM 02-01 Part A (2026), paragraph 5.33](https://www.england.nhs.uk/wp-content/uploads/2016/05/health-technical-memorandum-02-01-medical-gas-pipeline-systems-part-a-design-installation-validation-verification-aug-2026.pdf)
- [NHS Scotland, SHTM 02-01 Part A, Version 2 (August 2026), paragraphs 5.131 and 5.136](https://www.nss.nhs.scot/media/7005/shtm-02-01-part-a-v2-august-2026-3.pdf)
- [WHO, Technical specifications for PSA oxygen plants, interim guidance (8 June 2020)](https://iris.who.int/server/api/core/bitstreams/d53996d5-380c-44ae-9fe8-9e529d3270cd/content)
- [WHO, Technical specifications for health facility based medical oxygen systems (31 December 2024), 1.1 note (supersedes the 2020 interim PSA specifications)](https://iris.who.int/server/api/core/bitstreams/ff437601-add3-44c8-8149-b85f0cdb2b52/content)

Reviewed: 2026-10-23. Ultra Controlo engineering. https://library.ultracontrolo.com/standards/iso-21969/