# What ventilation does an oxygen plant room need?

**What ventilation and exhaust does a PSA oxygen plant room need?**

A PSA plant room needs ventilation that rapidly replaces oxygen-depleted air and holds the operating temperature: WHO (2023) asks for a housing conditioned to 5 to 35 °C, oxygen depletion sensors and a nitrogen vent outdoors, and AIGA 113/20 (EIGA Doc 195) recommends at least six air changes per hour.

WHO's Foundations of medical oxygen systems (2023) states that PSA oxygen generator plants require a dedicated housing conditioned to keep the inside temperature within an operational range of 5 to 35 °C, and that any decision to add mechanical ventilation should also consider its capacity to deplete an oxygen-enriched atmosphere in the room. The PATH and CHAI brief on PSA plants (July 2021) notes that the equipment generates substantial amounts of heat and requires adequate air conditioning for cooling.

## What the guidance asks for

- Air changes: AIGA 113/20, the Asia Industrial Gases Association edition of EIGA Doc 195 on on-site oxygen 93, recommends a minimum of six air changes per hour in the building, ventilation that prevents localised oxygen-deficient or oxygen-rich atmospheres, and a ventilation or air conditioning system that keeps room temperature and humidity within the manufacturer's operating range.
- Oxygen in the room: the same document asks for atmospheric oxygen to be monitored and kept between 19.5% and 23.5% wherever personnel work. WHO (2023) asks for adequate ventilation so that oxygen-depleted air is rapidly replaced, and for oxygen depletion sensors in the plant room.
- Air path: WHO (2023) recommends placing the air inlet opposite the air outlet, with ducting that keeps acceptable indoor conditions, and considering mechanical ventilation (air conditioning or heating) where the local climate does not allow the operating range to be kept.
- Openings: the plant room should have ducts for the water discharged by the water separator and openings for exhaust ventilation, cables and pipelines (WHO, 2023).
- Nitrogen vent: the nitrogen discharge duct should be vented to the atmosphere. WHO suggests that it ends at least 3 m clear of any door or window that can be opened and of any other ventilation or air intake, with its end turned downward to keep out dirt and moisture.

## Compressor exhaust and room exhaust

Assist International, answering on Open Critical Care, describes two exhaust systems in a PSA plant: the first directly exhausts the large compressor, and the second exhausts the room, so that it has good air circulation and a moderated temperature. Sometimes the air dryer also needs an exhaust.

## Checking it works

Global Fund commissioning guidelines (28 August 2024) ask for plant room ventilation to be confirmed as working, where relevant, and for the room to stay between 5 and 40 °C, or at the manufacturer's recommended temperature, for the duration of the commissioning tests. The Global Fund daily maintenance checklist then asks every day whether all ventilation systems, including fans, are working and whether the air intake filter mats, intake cover and ventilation filters are in place.

For ULTRAOX plants, the 2022 datasheet asks for ambient air at the site that is reasonably free from dust, at an acceptable level of humidity and free from chemical contamination, in a location whose electrical designation is not hazardous. Where no civil space or technical room is available, the datasheet offers the ULTRAOX CO, built inside a sea container.

### Why does oxygen enrichment matter in a plant room?

WHO (2023) warns that a gas leak in a poorly ventilated room can quickly raise the oxygen concentration to a dangerous level, and that even a rise from 21% to 24% can be hazardous because some materials become self-combustible.

### Where should the compressor take its air from?

AIGA 113/20 asks for concentrator units to be installed where the risk of air intake contamination from engine exhaust, ventilation and vacuum system discharges and scavenging systems is minimised.

## Sources

- [WHO, Foundations of medical oxygen systems (17 February 2023), sections 2.2.4, 3.5.1 and 3.6](https://www.who.int/publications/i/item/WHO-2019-nCoV-Clinical-Oxygen-2023.1)
- [AIGA 113/20 (adopted from EIGA Doc 195), On site generation of oxygen 93% for medicinal use, sections 6.2.1 and 6.2.2](https://asiaiga.org/uploaded_docs/en_AIGA_113_20_Generation_of_Oxygen_93_for_Medicinal_Use.pdf)
- [Open Critical Care FAQ (Assist International): What is PSA plant secondary room exhaust?](https://opencriticalcare.org/faq/what-is-psa-plant-secondary-room-exhaust/)
- [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)
- [Global Fund / Build Health International, Overview: PSA Oxygen Plant Commissioning Guidelines (28 August 2024)](https://resources.theglobalfund.org/media/qp3h1vxo/cr_c19rm-psa-oxygen-plant-commissioning_overview_en.pdf)
- [Global Fund / Build Health International, PSA plant Daily Maintenance Checklist (Project BOXER)](https://resources.theglobalfund.org/media/xbanfgrc/cr_c19rm-psa-plant-daily-maintenance_checklist_en.pdf)
- [ULTRAOX datasheet 2022, p. 9 and p. 19](https://www.ultracontrolo.com/ultraox)

Reviewed: 2026-10-22. Ultra Controlo engineering. https://library.ultracontrolo.com/answers/what-ventilation-does-an-oxygen-plant-room-need/