This British Standard specifies requirements and test methods for the
composition and purity of breathing gases, other than compressed air,
for use in diving and hyperbaric applications.
The standard is applicable to the following categories of gas mixtures:
a) breathing oxygen;
b) oxygen and nitrogen gas mixtures (known as nitrox);
c) oxygen and helium gas mixtures (known as heliox);
d) oxygen, helium and nitrogen gas mixtures (known as trimix).
The standard is not applicable to compressed gases for medical use, or
to gases for use in high altitude breathing apparatus.
NOTE 1 The composition and purity of compressed air is specified
in BS EN 12021.
NOTE 2 If compressed air for a diving application is intended for
creating a nitrox mixture this compressed air (also known as “oxygen
compatible air”) is considered to be nitrox and is subject to the
requirements specified in this standard.
BS 8478:2006 history
2014BS EN 12021:2014 Respiratory equipment. Compressed gases for breathing apparatus
2011BS 8478:2011 Respiratory protective devices. Breathing gases for diving and hyperbaric applications. Requirements and test methods
2006BS 8478:2006 Respiratory protective devices - Breathing gases for diving and hyperbaric applications