scope:

This section of IEC 534-8 includes the method for measuring the sound pressure level due to liquid flow through a control valve and the method for determining the characteristic increase of noise due to the onset of cavitation. It also defines the equipment, methods and procedures for the laboratory measurement of the airborne sound needed to determine these characteristics. The airborne sound includes that radiated from the control valve and the associated piping configuration, including fixed flow restrictions through which the test fluid (water) is passing. The primary purpose of this section of IEC 534-8 is to provide a method for determining the characteristic increase of noise due to cavitation, including a method for measuring noise generated in control valves by hydrodynamic flow. Methods of measuring the noise radiated from the valve and associated test piping allows a comparison of various measured data which is beneficial to the user and the manufacturer. The noise to be measured takes into account the noise radiated from the control valve itself and the noise generated by the valve but radiated from the associated piping system. The test data are expressed as sound pressure levels of the valve under consideration using water as the test fluid. Determination of sound power levels is beyond the scope of this section of IEC 534-8.