This document specifies: - the field of application; - the requirements for in-line anti-vacuum valves; - the dimensional, the physico-chemical properties and the properties of general hydraulic, mechanical and acoustic design to which in-line anti-vacuum valves of nominal sizes DN 8 up to and including DN 80; - the test method and requirements for verifying these properties - the marking and the presentation; - the acoustics. This document specifies the characteristics of one type of in-line anti-vacuum valves of nominal size DN 8 up to and including DN 80 that are suitable for use in drinking water systems at pressures up to and including 1 000 kPa (10 ba