Specifies the levels of purity and analysis of compressed medical breathing air supplied by a pipeline directly from an air compressor. Definitions, purity of medical breathing air in terms of maximum allowable concentration of contaminants, and suggested methods of analysis are included. Does not apply to medical breathing air supplied from cylinders, compressed air for laboratory use, air for driving of suction venturis and process control, air for surgical tools for dental purposes, and other purposes not involving respiration.