This part of ISO 8835 specifies requirements for anaesthetic breathing systems that are supplied either assembled by the manufacturer or for assembly by the user in accordance with the manufacturer's instructions. It also covers circle absorber assemblies, exhaust valves, inspiratory and expiratory valves and, in some designs, those parts of an anaesthetic breathing system that are incorporated within an inhalation anaesthetic system, including the expiratory gas pathway of an anaesthetic ventilator. This part of ISO 8835 does not cover the performance of anaesthetic breathing systems regarding the elimination of expired carbon dioxide since this is complex and depends on the interaction of the patient, the fresh gas flow, the carbon dioxide absorbent and the anaesthetic breathing system itself. This part of ISO 8835 does not apply to anaesthetic breathing systems intended for use with flammable anaesthetic agents/gases as determined by Annex DD of IEC 60601-2-13:2003.