Can VSA oxygen plants be used in hospitals?

WHO's Foundations of medical oxygen systems (2023) explains the difference: PSA plants use a compressor to push the air through the sieve beds, while VSA plants use a vacuum system to draw the gas into the production equipment. NHS England's HTM 02-01 (2026) notes that using vacuum to remove the nitrogen increases the efficiency of the regeneration and adsorption process.

What a hospital VSA plant needs

• A booster: PATH and CHAI (2021) say VSA plants produce oxygen at a much lower pressure than PSA plants and often need an additional high-pressure oxygen compressor for hospital pipelines; WHO (2023) says an oil-free booster compressor is generally added, and the Global Fund briefing note (March 2025) lists an additional oil-free oxygen booster compressor for distribution.
• Service support: the same Global Fund note says VSA needs highly specialised, very expensive maintenance tools, and that where VPSA or VSA plants are not common, spare parts supply chains and maintenance support may not be optimal. Its main recommendation is the technology already common and functional in the region.
• Quality guidance: AIGA 113/20, adopted from EIGA Doc 195, is written for PSA but says its principles may be applied to VSA.

What VSA offers

WHO (2023) lists VSA advantages: an oil-free blower that lowers filtration needs and removes the risk of oil carry-over, higher efficiency in humid environments because no air dryer is needed, operation less affected by altitude, and sieve beds with a longer projected lifespan. PATH and CHAI (2021) call VSA systems more energy-efficient, with lower operating costs, but with a higher upfront capital cost than a comparable PSA plant. UNDP's requirements (effective 1 January 2025) add lower power consumption, particularly for larger capacities, and reduced condensate risk.

Market availability

WHO (2023) notes that VSA availability for medical use is restricted by the low number of manufacturers and suppliers marketing it, while PSA is more commonly available. UNDP prioritises PSA plants in its requirements because of broader market availability, well-established supply chains and extensive service networks, and says most of its technical requirements also apply to VSA and VPSA. For a side-by-side view, see PSA, VSA and VPSA compared.

ULTRAOX VSA is an industrial line

The Ultra Controlo VSA plant, ULTRAOX VSA, is an industrial line: its datasheet gives 75% to 95% oxygen at 50 kPa, with higher pressures available through an additional oxygen booster on demand, for uses such as aquaculture, wastewater treatment and gold leaching. The Ultra Controlo hospital plants, ULTRAOX SC and ST, use ULTRACON PSA generators and deliver 94% (±1%) oxygen at 6 bar. See industrial VSA oxygen plants.