This European Standard specifies the characteristics and the requirements of air gap with non-circular overflow (unrestricted) Family A, Type B for nominal flow velocity not exceeding 3 m/s. Air gaps are devices for protection of potable water in water installations from pollution by backflow. This European Standard applies to air gaps in factory-assembled products and to constructed air gaps in situ, and defines requirements and methods to verify and ensure compliance with this European Standard during normal working use.