# Can oxygen concentrators back up a failed PSA plant?

**Can bedside oxygen concentrators be used as backup when a hospital PSA plant or pipeline fails?**

WHO-UNICEF guidance (2019) describes cylinders as a backup for other oxygen systems, while bedside concentrators themselves require uninterrupted power and backup cylinders, and their low-pressure output is usually not suitable for CPAP or ventilators; WHO's COVID-19 guidance (2020) called them plug-and-play options limited in the volume they can deliver.

## What a bedside concentrator can supply

- Flow: WHO-UNICEF (2019) gives a maximum of 5 to 10 L/min for home care and bedside models, and PATH and CHAI (July 2021) a typical maximum of 3 to 12 L/min, above 20 L/min in some units. WHO-UNICEF adds that, with a flowmeter stand that splits the flow, one concentrator can supply several patients at the same time.
- Pressure: PATH and CHAI give output pressures of 30 to 135 kPa, which may be insufficient for some equipment, and note that most ventilators need a 50-psi gas supply.
- Power: WHO-UNICEF says concentrators need a continuous and reliable power source and regular preventive maintenance; PATH and CHAI add that generators or a UPS can help provide oxygen during power outages.
- Approval and checks: PATH and CHAI say concentrators must be approved by the national regulator or a stringent regulatory authority, and that a hand-held oxygen analyser must be available at any facility with concentrators.

## Why cylinders are named as the backup

In the WHO-UNICEF comparison of oxygen sources, cylinders can be used in facilities where power is intermittent or unreliable and are used as a backup for other systems, while both concentrators and PSA plants require uninterrupted power and a backup cylinder supply. WHO interim guidance (4 April 2020) also said oxygen plants require a reliable source of power and called it best practice to keep cylinders as a backup supply. PATH (November 2023) notes that without power, and without a backup energy source, a PSA plant cannot generate oxygen. See what backup to keep with a PSA plant and [what happens to a PSA plant in a power cut](https://library.ultracontrolo.com/answers/what-happens-to-a-psa-plant-in-a-power-cut/).

## Where WHO places concentrators

- During COVID-19, WHO (2020) advised adding bedside concentrators, if supply allowed, as a complementary approach while waiting for higher-flow solutions such as a PSA plant or liquid oxygen, and said that once a PSA plant is commissioned, concentrators can be reallocated to other health facilities.
- WHO's Foundations of medical oxygen systems (2023) lists bedside concentrators as inefficient for large-scale provision, suggests using them, where possible, for patients who need lower flows (under 10 L/min), and notes that keeping functional replacement concentrators ready to swap can avoid treatment interruptions.

The pipeline standard ISO 7396-1:2016 excludes oxygen concentrators for domiciliary use from its scope, and the International Pharmacopoeia monograph for medicinal oxygen (2025) does not apply to oxygen from portable concentrators for home care or bedside use. See PSA plant vs oxygen concentrators.

### Do pipeline standards cover bedside concentrators?

No. ISO 7396-1:2016 excludes oxygen concentrators for domiciliary use from its scope, and the International Pharmacopoeia (2025) monograph does not apply to portable concentrators for home care or bedside use.

### How many patients can one concentrator supply?

WHO-UNICEF (2019) says that, with a flowmeter stand for splitting flow, a concentrator can supply several patients at the same time, within its maximum of 5 to 10 L/min for bedside models.

## Sources

- [WHO-UNICEF, Technical specifications and guidance for oxygen therapy devices (14 January 2019), section 3.1 and Table 3.1](https://iris.who.int/server/api/core/bitstreams/5a996b5a-6803-486e-bccb-98efc398118d/content)
- [WHO, Oxygen sources and distribution for COVID-19 treatment centres, interim guidance (4 April 2020)](https://iris.who.int/server/api/core/bitstreams/17eea7fd-59d9-4523-86eb-acec74fcfd27/content)
- [WHO, Foundations of medical oxygen systems (17 February 2023), Table 1.2 and sections 1.6.1, 3.3.2 and 3.4.2](https://iris.who.int/server/api/core/bitstreams/4ad6f5fd-089e-4142-8439-b64e98d816d8/content)
- [PATH and CHAI, Oxygen Generation and Storage: Oxygen Concentrator (July 2021)](https://media.path.org/documents/O2_generation_and_storage_oxygen_concentrators_v2.pdf)
- [PATH, Pressure swing adsorption plants: Common issues and solutions to prevent future disrepair (November 2023)](https://media.path.org/documents/Root_cause_analysis_report_external_clean_v2.pdf)
- [ISO 7396-1:2016, scope (iso.org)](https://www.iso.org/standard/60061.html)
- [The International Pharmacopoeia, 13th edition (2025), Medicinal oxygen](https://digicollections.net/phint/202502/index.html#d/b.6.1.226)

Reviewed: 2026-10-22. Ultra Controlo engineering. https://library.ultracontrolo.com/answers/can-oxygen-concentrators-back-up-a-failed-psa-plant/