Can plastic pipe be used for medical vacuum or AGSS?

ISO 7396-1:2016 covers pipeline systems for compressed medical gases and vacuum in healthcare facilities, and EN 13348 is the European standard for seamless round copper tubes for medical gases or vacuum.

Medical gas pipeline systems

For medical vacuum, HTM 02-01 says the vacuum discharge and pipeline distribution system should be constructed of material and pipework in line with BS EN ISO 7396 and other associated British Standards for medical pipeline systems, with fire precautions to the HTM 05 Firecode series (15.13). Degreasing vacuum pipelines is not essential for quality, but because they are often installed at the same time as the medical gas pipelines, degreased pipe and fittings should be used for vacuum installations to avoid confusion (15.73). For the medical gas pipeline system, the HTM asks manufacturers to comply with BS EN ISO 7396-1 for pipes and all associated materials, including fittings, terminal units and related components, and specifies rigid copper pipework of grade CW024A (Cu-DHP), phosphorus-deoxidised, non-arsenical copper to BS EN 1412 (15.67, 15.68). Alternative materials 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 (15.67).

In Portugal, ACSS ET 03/2006 (v.2024) asks for the medical gas distribution networks to be built in copper tube to EN 13348, and allows flexible tubing to NP EN 739 where the network cannot be in copper, as in magnetic resonance rooms (7.1).

Anaesthetic gas scavenging

AGSS pipework is in contact with the patient's expired breath. HTM 02-01 notes that, although considerable dilution occurs within the receiving system, there remains a potential for microbiological contamination, so materials should be resistant to it and capable of withstanding cleaning, disinfection or sterilisation, as appropriate (12.22). Fixed AGSS pipework should be made of copper and, to avoid confusion, of degreased pipework of the same specification as the MGPS (12.23). For single-chair dental anaesthetic gas scavenging (DAGS), the exhaust should be routed externally in a pipe of at least 32 mm diameter, made of a material compliant with fire regulations and sleeved with a copper pipe one size larger (12.47).

Dental vacuum

For dental vacuum, HTM 02-01 names plastics. The dental vacuum and exhaust lines should be of materials resistant to attack from the substances carried and able to withstand a negative pressure of 25 kPa. ABS or ASA pipework is generally unsuitable, as it is susceptible to chemical attack, copper pipework in wet systems may be attacked by dental amalgam, and polyethylene, polypropylene and heat-welded uPVC have all been found suitable (11.51, 11.52). Non-metallic pipework passing through fire compartment walls or barriers should be suitably sleeved, and solvent, ultrasonic and heat welding are all suitable jointing techniques, or any method that ensures system integrity under vacuum (11.53, 11.54).