scope:

This part of ISO 19973 provides test procedures for determining the reliability of pneumatic directional control valves by testing and the methods of reporting the results of testing. General test conditions and the calculation method are provided in part 1 of ISO 19973. The methods specified in that part of ISO 19973 apply to the first failure without repairs, but exclude outliers. The lifetime of pneumatic and electro-pneumatic directional control valves is usually given as a number of cycles. Therefore, whenever the term "time" is used in this part of ISO 19973, this variable is be understood as cycles. This part of ISO 19973 also specifies test equipment and threshold levels for tests to determine the reliability of pneumatic directional control valves.