This standard specifies the requirements for Compressed Breathing Gases procured or produced for Aircraft, Diving and Marine Life-Support applications and provides reference methods of test. It includes high-pressure compressed natural breathing air supplies produced for diving, fire-fighting and emergency escape applications on board HM Ships and Submarines; and high and low pressure dedicated natural breathing air supplies for compression chambers.

NOTE 1: Low-pressure compressor systems producing compressed natural breathing air for air-line fed respiratory protection systems, such as paint spray booths, are excluded as these are covered by BS EN 12021 (See also JSP 375).

NOTE 2: Similarly, most high-pressure systems producing compressed natural breathing air for filling respiratory protective equipment, such as fire fighting cylinders, are excluded as these applications are also covered by BS EN 12021 (See also JSP 375).

NOTE 3: Pure Air procured or produced specifically for Detector Cooling Applications, is excluded as this is not a breathing gas and its requirements are specified in Def Stan 58-96.

It includes breathing gases procured in gas cylinders, encompassing compressed natural breathing air, oxygen / helium mixtures, oxygen / nitrogen mixtures, oxygen / nitrogen / helium mixtures; and breathing oxygen (in liquid and gaseous form). 

The maximum allowable contaminants in MSOCS-produced aircraft breathing gas and the supply pressures for aircraft oxygen systems are also specified.