WHO technical specifications for PSA oxygen plants

What the specification asked for

Status: interim guidance

WHO published the document, reference WHO/2019-nCoV/PSA_Specifications/2020.1, on 8 June 2020 during the COVID-19 response. The text stated that, as interim guidance, it would expire two years after publication, yet WHO still hosts it. WHO's Technical specifications for health facility based medical oxygen systems, published on 31 December 2024, state that their oxygen generator plant specification supersedes this interim guidance. Cite it as WHO interim technical specifications (2020), not as a WHO approval of any plant or manufacturer. It also reflected the standards of its time: it referenced the 2018 edition of NFPA 99, whose current edition is 2027.

What it means for hospitals and buyers

• Used as a tender checklist, each item should be checked against the current editions of the standards it cited and against national rules.
• The purity band of 93% ± 3 is the oxygen 93 range of 90% to 96% used in ISO 7396-1 and in Ph. Eur. 2455; WHO's Foundations of medical oxygen systems (2023) repeats that generator plant purity should be 93% ± 3%.
• A Global Fund briefing note (3 April 2024) shows why the band matters for capacity: a PSA plant giving 20 Nm³/h at 93% ± 3% would give 18 Nm³/h if set to 95% ± 1%.

Ultra Controlo products

Ultra Controlo is certified to ISO 13485:2016. Its ULTRAOX SC and ST datasheets state an oxygen purity of 94% (±1%) and an oxygen outlet pressure of 6 bar.