Pipeline systems
What tests are done when commissioning a medical gas pipeline?
Which tests are carried out before a new medical gas pipeline is accepted: leaks, cross-connection, particles, purity?
Short answer
Under NHS England's HTM 02-01 (2026), commissioning a medical gas pipeline involves pressure and leak tests on the pipework, cross-connection and valve zoning tests, terminal unit, flow and alarm tests, particulate tests and, last, quality control tests of gas identity and quality at the terminal units before the system is handed over for patient use.
ISO 7396-1 sets requirements for testing and commissioning of pipeline systems, and in Portugal ACSS ET 03/2006 asks for the tests to follow ISO 7396-1 and ISO 7396-2. A detailed public procedure is NHS England's HTM 02-01 (2026 edition), which divides the programme into four phases: pre-commissioning checks, tests on the pipeline carcass, tests of the complete system with second-fix terminal units using test gas, and identity, quality and purity tests on the medical gases by the Quality Controller (MGPS) before handover.
The tests in HTM 02-01
| Stage | Tests (HTM 02-01 form) |
|---|---|
| Carcass | Brazing inspection (B2); labelling, sleeving and supports (B4); carcass pressure test (B5), for example 1000 kPa for 400 kPa gases and 1800 kPa for surgical air |
| Supply system | Plantroom, manifold room and cylinder store compliance; air plant, pressure-reducing stations, vacuum plant, scavenging plant, manifolds and liquid systems (B8 to B14) |
| Pipeline | Pressure test at normal working pressure, or 200 kPa for negative pressure systems (B18); vacuum leakage test (B19); engineer's particulate test (B20); cross-connection test (B21) |
| Valves and outlets | Line valve and AVSU closure, zoning, NIST and identity tests (B22, B23); terminal unit tests (B24); purging and filling (B25); design flow performance (B26) |
| Alarms | Plant alarm tests (B27); local alarm tests (B28) |
| Quality control | Particulate test with the working gas (B29); identity and quality against the British Pharmacopoeia monographs at all terminal units, supply points and plant (B30) |
| Completion | Key register (B31); removal of the "Do not use" plugs (B32); completion certificate (B33) |
Engineering tests are carried out by a Competent Person (MGPS) and quality control tests by a Quality Controller (MGPS). The Authorising Engineer, Authorised Person and Quality Controller should be independent of each other and of the installer. All components are tested, with no batch or sample testing, and "Do not use" plugs stay in the terminal units until quality control is complete, so that no equipment can be connected to an untested pipeline.
The NFPA 99 sequence
The NFPA 99 2021 edition followed a similar logic in two steps; NFPA now lists the 2027 edition as current. Initial tests came first: after blowdown of the distribution piping, each section was pressure tested at 1.5 times the operating pressure, but not less than 1035 kPa (150 psi), with every joint checked with an oxygen-safe leak detectant. Verification then followed, and in the dental gas chapter of that edition it was performed by a party other than the installing contractor, certified for ASSE 6030, with tests including standing pressure, cross-connection, purge, particulate, purity, operational pressure and gas concentration. CSA Group describes CSA Z7396.1:22 as the governing standard for medical gas installations in health care institutions.
More questions
Who signs off a new medical gas pipeline?
In HTM 02-01 (2026), the appropriate persons certify in writing that all required tests are complete and the systems comply before use, and the completion certificate (form B33) involves the contractor's representative, Competent Person, Authorised Person, Quality Controller and Authorising Engineer.
What happens if handover is delayed?
HTM 02-01 asks for systems not handed over within 12 weeks of the engineering tests to be filled with medical air at 50% of the standard system pressure while awaiting quality control testing.
Sources
- HTM 02-01 (2026) Part A, chapter 19 (paragraphs 19.4, 19.28 to 19.31, 19.41 to 19.78, 19.289) and Tables 29 and 30, NHS England
- NFPA 99, 2021 edition text of 5.1.12.2.3 and 15.4.7, reproduced in NFPA committee input report HEA-PIP, 2021
- ISO 7396-1:2016, official summary
- ACSS ET 03/2006 v.2024, section 11 Ensaios, receção técnica e certificação
- CSA Z7396.1:22, CSA Group
- NFPA 99 document page (current edition 2027)
Ultra Controlo figures come from its technical datasheets. Third-party facts were read at the source on the date shown.