This part of this European Standard specifies minimum performance and safety requirements for air entrainment devices used for delivery of a designated oxygen concentration to patients. It gives a test method to check the oxygen concentration in the air/oxygen mixture generated by the air entrainment device. It also specifies marking requirements and gives an optional system of colour coding to assist the user to identify the designated oxygen concentration.This standard does not cover air entrainment devices which are integral with medical devices specified in other standards e.g. emergency lung ventilators, humidifiers, nebulizers, etc.