NEW RELEASE
This a European Norm: EN 12021 used to define the quality of the air breath in the PPE ( air hoods..) This norm also applies breathing gaz mixtures. Purity is measured under normal pressure and temperature with respect to
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oxygen 21% + or - 1%
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purity level
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The compressed air for respiratory apparatus must not contains impurity which may have toxic effect or cause health injuries. The purity level must be maintained at a value lower than the VLE/TWA or VLE/C or VLE/STEL.
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Content of lubricants ( aerosol or droplets) must not exceed 0,5 mg/m3. In case of synthetic lubricants, the above apply.
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new definition: mixture of hydrocarbon and other organic compounds containing six or more carbon atom
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The air must have no significant odour or taste
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The CO2 value must not exceed 500ml/m3 (500ppm)
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The CO value must not exceed 5ml/m3 (5ppm)
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Water content : - The air must not contain liquid water
- The dew point must not exceed -11°C whenn the used conditions are unknown
- The dew point must be 5°C below the most expected lower air value when used and storage conditions are known
http://www.boutique.afnor.org/search/results/word/BS%20EN%2012021