Oxygen-Enriched Atmosphere (OEA) 2 : An atmosphere in which the concentration of oxygen exceeds 21 percent by volume or its partial pressure exceeds 21. 3 kPa (160 torr)
NFPA 53 Recommended Practice on Materials, Equipment, and Systems Used in Oxygen-Enriched Atmospheres, 2004 ed. https://www.nfpa.org/assets/files/AboutTheCodes/53 /53-F2009-ROP.pdf, (Recmm Prac: on Mtrl, Equip and Sys Used in Oxy-Enriched Atm - Amer) {209 NFC}