Does medical vacuum pipework need degreased copper?

HTM 02-01 (2026) says degreasing is not essential for vacuum quality, but degreased pipe and fittings should be used so that vacuum and gas installations are not confused.

Can medical gas copper be joined with mechanical fittings?

HTM 02-01 (2026) allows mechanical connections where brazing would present an unavoidable serious fire risk, agreed by the Authorised Person (MGPS), with structural integrity comparable to brazed fittings and no elastomeric materials.

What copper pipe is used for medical gases?

Q: What copper tube is used for medical gas pipelines, and what does EN 13348 require?

EN 13348 is the European standard for seamless round copper tube for medical gas or vacuum pipelines, covering outside diameters from 6 mm to 219 mm at operating pressures up to 2 000 kPa; NHS England's HTM 02-01 and Portugal's ACSS call for it and for brazing under an internal nitrogen shield.

What copper tube is used for medical gas pipelines, and what does EN 13348 require?

What EN 13348 covers

EN 13348:2016 is the CEN product standard for seamless, round copper tubes for medical gas or vacuum pipelines. It sets requirements, sampling, test methods and delivery conditions for tubes from 6 mm up to and including 219 mm outside diameter, intended for operating pressures up to 2 000 kPa. National guidance calls for it directly: NHS England's HTM 02-01 (2026 edition) asks for pipes cleaned and degreased for oxygen service and free of particulate matter and toxic residues in accordance with BS EN 13348, and Portugal's ACSS specification ET 03/2006 asks for networks in copper tube to EN 13348.

Practice in NHS England's HTM 02-01 (2026)

Material: grade CW024A (Cu-DHP) phosphorus-deoxidised, non-arsenical copper to BS EN 1412, in metric outside diameters.
Tempers: R250 (half hard) in 15, 22, 28, 35, 42 and 54 mm, suitable for bending; R290 (hard) in 35, 42 and 54 mm and above, not for bending; R220 annealed coils.
Delivery: each pipe capped at both ends and identified as medical gas pipe; fittings individually sealed in plastic bags.
Fittings: end-feed capillary fittings to BS EN 1254-1.
Jointing: copper-to-copper joints brazed on site with silver-copper-phosphorus alloy CP104 to BS EN ISO 17672, with no flux, using LPG/oxygen torches; acetylene should not be used.
Inert shield: oxygen-free nitrogen flows through the pipe during brazing so that no oxides form inside.
Cutting: wheel pipe cutters only, not hacksaws, to keep copper particles out of the line.
Inspection: as a guide, one fitting in 200 is cut out and examined, with a minimum of two per pipeline; brazing alloy penetration should be at least three times the tube wall thickness or 3 mm, whichever is greater.

Outside diameter (mm)	Maximum interval between supports (m)
Up to 15	1.5
22 to 28	2.0
35 to 54	2.5
>54	3.0

The support intervals above are Table 27 of HTM 02-01 Part A. Degreased tube is also used for vacuum lines, not because vacuum needs it but to avoid confusion when the same contractor installs both. Alternatives to rigid copper, such as corrugated metal tubing, may be considered where full compliance with BS EN ISO 7396-1 is demonstrated and the product is CE-marked and validated by the Authorising Engineer (MGPS) and the Medical Gas Safety Group.

Rules differ by country

Portugal's ACSS ET 03/2006 (2024 revision) asks for joints made with nitrogen passing inside the tube and a filler with a minimum silver content of 40%, allows flexible tubing to NP EN 739 only where copper cannot be used, such as magnetic resonance rooms, and requires the networks to be earthed. Check the national specification before choosing the filler alloy, tube temper and joint inspection regime.