Medical air
How often should medical air quality be tested?
How often should a hospital test the quality of the medical air in its pipeline?
Short answer
HTM 02-01 (2026) sets quarterly quality control testing for medical and surgical air compressor plants, plus testing after installation, repairs, modifications and supply interruptions; dental air plants are tested quarterly as recommended and at least annually.
HTM 02-01 is the NHS England guidance for medical gas pipeline systems. Its Table 33 lists the routine quality control testing frequencies for gases made on site:
| Plant | Routine QC testing (HTM 02-01 Table 33) |
|---|---|
| Medical and surgical air compressor plants | Quarterly |
| Dental air compressor plants | Quarterly recommended, annually as a minimum |
| Synthetic air plants | Quarterly |
| Oxygen generator plants | Quarterly |
When else to test
- After the installation of a new medical gas pipeline system.
- After a planned extension, upgrade, modification or repair that interrupts the supply, and after an unplanned interruption.
- Ad hoc, when routine compressor plant results are anomalous or the Authorised Person (MGPS) raises a concern.
- In low-usage or dormant areas, and in empty wards or departments before they reopen for patients.
- After compressor work that replaces oil-sealing components, with a follow-up oil test.
What a routine test covers
Routine testing checks the gas against the acceptance criteria in HTM 02-01 Table 34: oxygen content, particles, carbon monoxide, carbon dioxide, sulphur dioxide, oxides of nitrogen, water vapour, oil and odour. The oil test is carried out at the plant test point at the Table 33 frequency.
Other countries set their own requirements, so outside England the national specification applies. Between tests, continuous dew point monitoring watches the dryers: ULTRAAR ME, for example, has two ULTRAGEST systems that monitor and control the dew point continuously.
More questions
Who carries out the quarterly tests?
In the UK, a Quality Controller (MGPS), whose regular planned testing includes the quarterly testing of compressor plant.
Does a small dental surgery need quarterly testing?
For dental surgeries with up to five chairs, HTM 02-01 sets air quality testing at least annually and recommends quarterly testing as a risk-based decision.
Sources
- NHS England, HTM 02-01 Medical gas pipeline systems (2026), Part A, chapter 20, Table 33 and Table 34
- ULTRAAR ME datasheet, p. 2
Ultra Controlo figures come from its technical datasheets. Third-party facts were read at the source on the date shown.