... the „breathing air standard“
Respiratory equipment - Compressed gases for breathing apparatus
Second edition (2014)
(DIN) EN 12021 specifies
- terms and definitions
- reference conditions
- 1,013 bar ; 20°C (atmospheric reference condition)
- all relative figures are given as percentage of volume (dry gas)
- requirements for
- breathing air
- oxygen compatible air (treated natural air offering (21±1)% O2)
- nitrogen depleted and oxygen enriched air (Nitrox)
- breathing oxygen
- oxygen and nitrogen gas mixtures
- oxygen and helium gas mixtures (Heliox)
- oxygen-, helium and nitrogen gas mixtures (Trimix)
- further informative content (annex)
Beside the general exclusion of toxic or harmful effects this standard specifies requirements for the oxygen, carbon dioxide, carbon monoxide, oil and humidity content within the breathing air. Furthermore, the breathing air shall be free of odours and taste.
With mixtures, the first figure describes the oxygen, the second figure the helium content. The “remaining” nitrogen content is a result of the mixture and thus not stated.
- Breathing air – EN 12021
- Oxygen – EN 12021
- Nitrox – 30 – EN 12021 = (30 ± 1)% oxygen [ and (70 ± 1)% nitrogen ]
- Heliox – 14/86 – EN 12021 = (14 ± 0,5)% oxygen and (86 ± 0,5)% helium
- Trimix – 16/40 – EN 12021 = (16 ± 0,5)% oxygen and (40 ± 1)% helium [ and (44 ± 1,5)% nitrogen ]
Unfortunately, the actual edition of ISO 8573-1 does not specify a designation in order to describe the requirements of EN 12021 to the compressed air. Thus, there is no reference between these two standards.
Robust and comprehensive standard for (industrial) breathing air.
Pretty complex and non-distinctive decision tree to determine the required humidity content.