This part of ISO 6953 specifies test procedures and a method of presenting the results concerning the parameters which define the main characteristics to be included in literature from suppliers of regulators and filter-regulators conforming to ISO 6953-1. The purpose of this part of ISO 6953 is the following: — to facilitate the comparison of pressure regulators and filter-regulators by standardizing test methods and presentation of test data; — to assist in the proper application of pressure regulators and filter-regulators in compressed air systems. The tests specified are intended to allow comparison among the different type of regulators and filter-regulators; they are not production tests to be carried out on each pressure regulator or filter-regulator manufactured. NOTE 1 The tests related to electro-pneumatic pressure control valves are specified in ISO 10094−2. NOTE 2 Use ISO 6953-3 for an alternative dynamic test method for flow-rate characteristics using an isothermal tank instead of a flow meter. However, this method measures only the decreasing flow rate part of the hysteresis curve of forward flow and relief flow characteristics.