# Copper vs stainless steel for medical gas pipes

For medical gas pipelines, EN 13348 is the European product standard for seamless copper tube, and both NHS England's HTM 02-01 (2026) and Portugal's ACSS ET 03/2006 call for copper; HTM 02-01 mentions stainless steel among materials that may suit other fittings connected to copper pipes, such as valve fittings.

EN 13348:2016 applies to seamless round copper tubes from 6 mm up to 219 mm outside diameter for medical gas or vacuum pipelines at operating pressures up to 2 000 kPa. In Portugal, technical compressed air, which may not be used for therapeutic purposes, falls under a different specification, ACSS ET 08/2010, which allows stainless steel pipe.

## What each document says about the pipe

| Document | What it says about pipe material |
|---|---|
| EN 13348:2016 (current, DIN Media listing) | Seamless round copper tube, 6 to 219 mm outside diameter, for medical gases or vacuum at operating pressures up to 2 000 kPa |
| HTM 02-01 (2026), NHS England, Part A, 15.67 to 15.71 | Rigid copper pipework, Grade CW024A (Cu-DHP) to BS EN 1412, cleaned and degreased for oxygen service in accordance with BS EN 13348; other fittings for connection to copper pipes, for example valve and control panel fittings, of copper, brass, gunmetal, bronze or stainless steel may be suitable |
| ACSS ET 03/2006 v.2024 (Portugal, medical gases) | Copper tube to EN 13348; flexible tubing to NP EN 739 where copper cannot be used, for example in MRI |
| ACSS ET 08/2010 V.2025 (Portugal, technical compressed air, not medical gases) | Deoxidised and degreased copper tube, stainless steel pipe of the AISI 304L or AISI 316L series, or treated aluminium pipe |

HTM 02-01 also allows for other materials: alternatives to rigid copper, such as corrugated metal tubing, may be considered where full compliance with BS EN ISO 7396-1 can be demonstrated and the product is CE-marked and validated to the satisfaction of the Authorising Engineer (MGPS) and the Medical Gas Safety Group. It asks manufacturers to comply with BS EN ISO 7396-1 for the production of pipes and all associated materials, including fittings and terminal units.

## Joining copper pipe

- HTM 02-01 says that, apart from mechanical joints, only copper-to-copper joints should be permitted on site, brazed with a silver-copper-phosphorus alloy CP104 to BS EN ISO 17672 and no flux.
- HTM 02-01 also says brazing should be done with oxygen-free nitrogen as an internal inert gas shield, to prevent oxides forming inside the pipes and fittings.
- ACSS ET 03/2006 asks for joints brazed with an inert gas (nitrogen) passing inside and solder with at least 40% silver.

The ACSS ET 08/2010 specification for technical compressed air (revised November 2025) excludes medical air and instrument air, which stay under ET 03/2006. See [what copper pipe is used for medical gases](https://library.ultracontrolo.com/answers/what-copper-pipe-is-used-for-medical-gases/) and [why medical gas pipes must be oxygen clean](https://library.ultracontrolo.com/answers/why-must-medical-gas-pipes-be-oxygen-clean/).

The Ultra Controlo accessory range includes a copper shut-off ball valve for isolating medical gas pipeline sections during installation, maintenance or an emergency.

### Can stainless steel pipe be used for technical compressed air in Portuguese hospitals?

ACSS ET 08/2010 (V.2025), the Portuguese specification for technical compressed air, allows stainless steel pipe of the AISI 304L or AISI 316L series; it excludes medical air and instrument air.

### Why must medical gas copper pipe be cleaned?

HTM 02-01 (2026) asks for all pipes to be cleaned and degreased for oxygen service and free of particulate matter and toxic residues, in accordance with BS EN 13348.

## Sources

- [DIN EN 13348:2016-11 (EN 13348:2016), DIN Media](https://www.dinmedia.de/en/standard/din-en-13348/253294458)
- [NHS England, HTM 02-01 Part A (2026 edition), paragraphs 15.67 to 15.71, 15.83 and 15.84](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)
- [ACSS ET 03/2006 v.2024, Gases medicinais e aspiração, section 7.1](https://www.acss.min-saude.pt/wp-content/uploads/2016/10/ET-03_2006_v2024-Gases-medicinais_VF.pdf)
- [ACSS ET 08/2010 V.2025, Ar comprimido técnico em edifícios hospitalares](https://www.acss.min-saude.pt/wp-content/uploads/2016/10/ET-08_2010_V.2025_VF.pdf)
- [Ultra Controlo, shut-off copper ball valve](https://www.ultracontrolo.com/accessories/shut-off-copper-valve)

Reviewed: 2026-10-22. Ultra Controlo engineering. https://library.ultracontrolo.com/compare/copper-vs-stainless-steel-medical-gas-pipe/