BS EN 60534-8-4 is a part of the IEC 60534 series. BS EN 60534-8-4 establishes a method to predict the noise generated in a control valve by liquid flow and the resulting noise level measured downstream of the valve and outside of the pipe. The noise may be generated both by normal turbulence and by liquid cavitation in the valve. Parts of the method are based on fundamental principles of acoustics, fluid mechanics, and mechanics. The method is validated by test data.
This prediction method has been validated with test results based on the water covering a majority of control valve types, in the DN 15 to DN 300 size range, at inlet pressures up to 15 bar. However, some types of low noise valves may not be covered. This method is considered accurate within ± 5 dB(A), for most cases, if based on tested values of xFZ using the method from IEC 60534-8-2. The applicability of this method for fluids other than water is not known at this time.
BS EN 60534-8-4 on noise in control valves is useful for:
It is valuable to predict the noise levels that will be generated by valves. Safety requirements, such as the occupational health standards require that human exposure to noise be limited. There is also data indicating that noise levels above certain levels could lead to pipe failure or affect associated equipment. See IEC 60534-8-3. A valve restricts flow by converting pressure energy into turbulence, heat, and mechanical pressure waves in the fluid contained within the valve body and piping. A small portion of this mechanical vibration is converted into acoustical energy. Most of the noise is retained within the piping system with only a small portion passing through the pipe wall downstream of the valve. Calculation of the mechanical energy involved is straightforward. The difficulties arise from determining first the acoustic efficiency of the mechanical energy to noise conversion and then the noise attenuation caused by the pipe wall.
BS EN 60534-8-4 considers only noise generated by normal turbulence and liquid cavitation. BS EN 60534-8-4 does not consider any noise that might be generated by mechanical vibrations, flashing conditions, unstable flow patterns, or unpredictable behavior. In the typical installation, very little noise travels through the wall of the control valve body. The noise predicted is that which would be measured at the standard measuring point of 1 m downstream of the valve and 1 m away from the outer surface of the pipe in an acoustic free field. Ideal straight piping is assumed. Since an acoustic-free field is seldom encountered in industrial installations, this prediction cannot guarantee actual results in the field.
BS EN 60534-8-4:2015 supersedes BS EN 60534-8-4:2005, which is withdrawn. BS EN 60534-8-4:2015 includes some technical changes with respect to BS EN 60534-8-4:2005. These include:
EN 60534-8-4:2015
IEC 60534-8-4:2015