# Bacterial filter

A bacterial filter is a fine filter that retains micro-organisms carried by a gas; in hospitals it is fitted in the medical vacuum plant, between the pipeline and the pumps, and it is one of the filters of medical air treatment.

On a medical vacuum plant, HTM 02-01 (2026) asks for duplex subassemblies, each with at least one bacteria filter and a drainage trap with a clear collection flask, and isolating valves that let either set run alone at full plant capacity. The filter is marked “biohazard” with a safe procedure for changing and disposal, it should comply with BS 3928, and the pumps should produce a higher vacuum than the pipeline needs, to overcome its resistance.

In medical air plants, HTM 02-01 lists a bacteria filter among the filters of each dryer assembly, with the dew point sensor and test point located after it.

The basic ULTRAVAC configuration includes two bacterial filters with liquid separator. On ULTRAAR ME medical air plants, each pressure regulator has a sterile air filter of 99.999998% efficiency at 0.01 µm, and for the ULTRAMED air treatment station Ultra Controlo advises adding a sterile air filter when it produces medical air.

## Sources

- [HTM 02-01 (2026) Part A, paragraphs 7.64, 7.68, 10.23 to 10.26 and 10.45 (NHS England)](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)
- [ULTRAVAC datasheet, p. 2](https://www.ultracontrolo.com/products/ultravac)
- [ULTRAAR ME datasheet, p. 3](https://www.ultracontrolo.com/products/ultraar-me)
- [ULTRAMED datasheet, p. 3](https://www.ultracontrolo.com/products/ultramed)

Reviewed: 2026-10-22. Ultra Controlo engineering. https://library.ultracontrolo.com/glossary/bacterial-filter/