SN EN 60534-8-3 : 2000

INTRODUCTION
1 Scope and limitations
2 Normative references
3 Definitions
4 Symbols
5 Valves with standard trim
      5.1 Pressures and pressure ratios
      5.2 Regime definition
      5.3 Preliminary calculations
      5.4 Regime I (subsonic flow)
      5.5 Regimes II to V (common calculations)
      5.6 Noise calculations
      5.7 Calculation flow chart
6 Valves with noise-reducing trim
      6.1 Introduction
      6.2 Single stage, multiple flow passage trim
      6.3 Single flow path, multistage pressure reduction
             trim (two or more trottling steps)
      6.4 Multipath, multistage trim (two or more passages
             and two or more stages)
      6.5 Valves not included in this standard
7 Valves with higher outlet Mach numbers
      7.1 Introduction
      7.2 Calculation procedure
Annex A (informative) Calculation examples
Annex ZA (normative) Normative references to international
                     publications with their corresponding
                     European publications
Bibliography
Figure 1 - Single stage, multiple flow passage trim
Figure 2 - Single flow path, multistage pressure reduction
           trim
Figure 3 - Multipath, multistage trim (two or more passages
           and two or more stages)
Table 1 - Numerical constants N
Table 2 - Typical values of valve style modifier Fd (full
          size trim)
Table 3 - Acoustic power ratio rw
Table 4 - Frequency factors Gx and Gy

Gives a theoretical method to predict the external sound-pressure level generated in a control valve by the flow of compressible fluids: considers only single-phase dry gases and vapours, based on the perfect gas laws.Does not cover any noise generated by reflections, mechanical vibrations, unstable flow patterns and other unpredictable behaviour, but addresses the noise generated by aerodynamic processes in valves and connected piping.