ISO 9635-4:2014规定了空气阀的结构、性能要求和试验方法，这些空气阀用于在温度不超过60°C的灌溉系统中运行，其中可能含有肥料和农业中使用的其他类型和浓度的化学品。 它适用于直径为DN 15或更大的液压操作空气灌溉阀，设计为直接操作，即通过浮子直接或通过机械连杆将力施加到闭孔器上。这些阀门可以通过可调先导阀施加的力来操作。

ISO 9635-4:2014 specifies construction and performance requirements and test methods for air valves, intended for operation in irrigation systems with water at temperatures not exceeding 60 °C, which can contain fertilizers and other chemicals of the types and concentrations used in agriculture. It is applicable to hydraulically operated air irrigation valves of DN 15 diameter or greater, designed to be directly operated, i.e. the force is applied to the obturator by the float, either directly or via a mechanical linkage. The valves can be operated by a force applied through an adjustable pilot valve.