BS EN 13077:2018 Devices to prevent pollution by backflow of potable water. Air gap with non-circular overflow (unrestricted). Family A. Type B

Flow control
Prefabricated parts
Valves
Water supply (buildings)
Water pollution
Overflows
Water
Anti-siphonage systems
Water supply engineering
Pollution control
In-situ construction
Pipework systems
Fluid inlets
Potable water
Pipes
Pollution

Link: BS EN 13077:2018 Devices to prevent pollution by backflow of potable water. Air gap with non-circular overflow (unrestricted). Family A. Type B
Source: BSI Standards