BS EN 12021:2014 free download.Respiratory equipment — Compressed gases for breathing apparatus.
BS EN 12021 specifies requirements for the quality of compressed gas supplied for mixing or use in respiratory protective devices and hyper- and hypobaric operations. Account is taken of the use of compressed gases for normal atmospheric pressure as well as for hyper- and hypobaric pressures.
This European Standard does not apply to compressed gases used for medical purposes or for aerospace applications.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references. the latest edition of the referenced document (including any amendments) applies.
EN 132:1998. Respiratory protective devices – DefInitions of terms and pictograms
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 132:1998 and the following apply.
hydrocarbon organic compound consisting of hydrogen and carbon
3.2 oil mixture of hydrocarbons and other organic compounds composed of six or more carbon atoms (C6+)
3.3 trimix gas comprising a specified mixture of oxygen, helium and nitrogen, capable of supporting human life under appropriate diving or hyperbaric conditions
Note I to entry: This includes manufactured gas mixtures made up from combinations of pure oxygen, pure heOum and pure nitrogen, with or without compressed air.
3.4 heliox gas comprising a specified mixture of oxygen and helium, capable of supporting human life under appropriate diving or hyperbaric conditions
3.5 oxygen and nitrogen gas mixture gas comprising a specified mixture of oxygen and nitrogen, capable of supporting human life under appropriate diving or hyperbaric conditions
4 Units
General use of SI units (see ISO 80000) as given throughout this International Standard is recommended. However, in agreement with accepted practice, some non-preferred SI units accepted by ISO are also used.
EXAMPLE 100 kPa = 100 bar.
IMPORTANT — The acronyin ppm (parts per million) is used throughout the world to indicate the absolute content of a substance within a mixture. So in this case the ml rn’3 equivalent notation ppm” has been used in brackets in the tables. In this European Standard ppm is understood as concentration of a gas in parts per million per volume.
5 Reference conditions
All data given in the tables or required in this European Standard are valid for normal atmospheric pressure
(1 013 mbar absolute, 20 C). All percentage requirements are given in % by volume (dry gas).
All pressures in this European Standard are in bar absolute.
Typical composition of natural air is given in Annex A.
Maximum allowable concentrations of impurities for compressed gases are quoted as values calculated at normal atmospheric pressure.
6 Requirements
6.1 General
Compressed gas bc breathing shall not contain contaminants at a concentration which can cause toxic or harmful effects. In any event, all contaminants shall be kept to as low a level as possible and shall be less than one tenth of a national 8 h exposure limit. For breathing air only the limit shall be less than one sixth of a national 8 h exposure limit. For breathing at hyperbaric pressures greater than 10 bar or exposure times greater than 8 h the levels shall be revised to take into account the effects of pressure and exposure times.
In the absence of more stringent nahonal regulations, the values in Table 1 to Table 10 shall be applied.
6.2 Breathing air
Typical composition of natural air is given in Annex A.
Compressed breathing air shall have a dew point sufficiently low to prevent condensation and freezing. Where the apparatus is used and stored at a known temperature the pressure dew point shall be at least 5 °C below the likely lowest temperature.
Where the conditions of usage and storage of any compressed air supply is not known the pressure dew point shall not exceed -11 °C.BS EN 12021 pdf download.
BS EN 12021:2014 free download
PS:Thank you for your support!
