# What pressure does a PSA oxygen plant deliver?

**At what pressure does a PSA oxygen plant deliver oxygen to the hospital pipeline?**

The 2020 WHO interim specification for PSA plants (superseded in 2024), from its COVID-19 series, asked for 300 to 600 kPa (3 to 6 bar) continuous output; ULTRAOX SC and ST plants are listed at 6 bar, and NHS England's HTM 02-01 (2026) gives 400 kPa as the nominal pressure of oxygen pipelines.

| Source | Pressure | What it refers to |
|---|---|---|
| WHO interim PSA specification (8 June 2020, COVID-19 series) | 300 to 600 kPa (3 to 6 bar); alarm below 3 bar | Continuous output pressure of the plant |
| Global Fund / BHI briefing note (4 March 2025) | 3.5 to 5 bar; about 4 bar | PSA oxygen at the end of the system, deliverable to wall outlets; pressure at the generator outlet, often suitable for delivery |
| PATH and CHAI (July 2021) | 50 to 55 psig (NFPA 99) or 400 to 500 kPa (ISO, piping only) | Continuous output pressure in basic specifications |
| HTM 02-01 (2026), NHS England | 400 kPa | Nominal pressure of oxygen pipelines |
| AIGA 113/20 | 8 to 9 bar(g) | Nominal pressure of a double-stage pipeline system, where a booster may be needed |
| ULTRAOX SC and ST datasheets | 6 bar oxygen outlet; 7.5 bar air inlet | Every model in the tables |

The Global Fund note says a PSA air compressor pressurizes the incoming air to 4.5 to 7 bar, and the 2020 WHO interim specification asked for a feed air compressor of at least 750 kPa. The ULTRAOX datasheet (2022) states that every 1 bar increase in compressor pressure adds 7% to total electricity consumption, and that the plant is designed to keep a continuous stable pressure in the oxygen network.

AIGA 113/20, adopted from EIGA Doc 195, requires a pressure reducing station whenever the produced or stored pressure is higher than the pipeline distribution pressure. It says a booster compressor could be needed to reach the nominal pipeline pressure of EN ISO 7396-1, usually only for a double-stage distribution system, where the nominal pressure is 8 to 9 bar(g). The Global Fund lists as a PSA benefit that oxygen leaves the generator at about 4 bar, often suitable for delivery, without an additional booster; where national standards require piping above 6 bar, it says a medium pressure booster can raise 4 to 6 bar up to 11 to 12 bar.

The 2020 WHO interim specification placed a gauge or sensor between the source and the line pressure control to monitor the output pressure. For pressures across the hospital network, see [what pressures do medical gas pipelines run at](https://library.ultracontrolo.com/answers/what-pressures-do-medical-gas-pipelines-run-at/).

### Does a PSA plant need a booster to feed the pipeline?

Not usually. The Global Fund (2025) says PSA oxygen leaves the generator at about 4 bar, often suitable for delivery; AIGA 113/20 says a booster is usually only needed for double-stage pipelines at 8 to 9 bar(g).

### Why not run the compressor at a higher pressure?

The ULTRAOX datasheet (2022) states that every 1 bar increase in compressor pressure adds 7% to total electricity consumption.

## Sources

- [WHO, Technical specifications for PSA oxygen plants, interim guidance (8 June 2020)](https://www.who.int/publications/i/item/WHO-2019-nCoV-PSA_Specifications-2020.1)
- [Global Fund / Build Health International, Briefing Note: PSA, VPSA and VSA (4 March 2025)](https://resources.theglobalfund.org/media/dp3clsrr/cr_c19rm-psa-vpsa-vsa_technical-briefing-note_en.pdf)
- [PATH and CHAI, Oxygen Generation and Storage: Pressure/Vacuum Swing Adsorption Plant (July 2021)](https://media.path.org/documents/O2_generation_and_storage_PSA_VSA_v1.pdf)
- [NHS England, HTM 02-01 Part A (2026), Table 30](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)
- [AIGA 113/20 (adopted from EIGA Doc 195), On site generation of oxygen 93% for medicinal use, sections 4.3.1 and 6.15.2](https://asiaiga.org/uploaded_docs/en_AIGA_113_20_Generation_of_Oxygen_93_for_Medicinal_Use.pdf)
- [ULTRAOX SC datasheet, p. 5](https://www.ultracontrolo.com/products/ultraox)
- [ULTRAOX ST datasheet, p. 5](https://www.ultracontrolo.com/products/ultraox-st)
- [ULTRAOX datasheet 2022, p. 5 and p. 6](https://www.ultracontrolo.com/ultraox)
- [WHO, Technical specifications for health facility based medical oxygen systems (31 December 2024), note on the oxygen generator plant specification (supersedes the 2020 interim PSA specifications)](https://iris.who.int/server/api/core/bitstreams/ff437601-add3-44c8-8149-b85f0cdb2b52/content)

Reviewed: 2026-10-22. Ultra Controlo engineering. https://library.ultracontrolo.com/answers/what-pressure-does-a-psa-plant-deliver/