1.1 This specification covers breathing systems and components employed with anesthesia gas machines for humans. This specification considers the circle system as a whole and some of its components individually. A particular emphasis is placed upon component arrangement in the circle absorber-type system, and submits a system of standard description and notation. Excluded are ventilators for use during anesthesia, Mapelson nonrebreathing type systems, as well as breathing systems and related components of dental analgesia machines. (For rationale, see Appendix X1.)

1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

1.3 This specification is arranged as follows: SectionScopeReferenced DocumentsTerminologySystem ClassificationGraphic NotationsDiagramatic RulesFunctional Segments of the Circle SystemTest Procedures-GeneralSterilizationSystemsLeakage of Breathing SystemResistance of Breathing SystemsVolume of Gas Not Delivered to Patient Due to Internal ComplianceMonitoring RequirementsAdjustable Pressure-Limiting (APL) ValvesReservoir BagsCO2 AbsorbersUnidirectional ValvesRequirementsTest ProcedureOptional ComponentsBreathing TubesFresh Gas Inlet and Fresh Gas Supply Tube or HoseConnectorsPressure GaugesY-Piece and Breathing TubesInformation in LabelingRationale