IEC 60534-8-3:2010 establishes a theoretical method to predict the external sound-pressure level generated in a control valve and within adjacent pipe expanders by the flow of compressible fluids. This method considers only single-phase dry gases and vapours and is based on the perfect gas laws. It is assumed that the downstream piping is straight for a length of at least 2 m from the point where the noise measurement is made. The method is applicable to the following single-stage valves:
- globe (straight pattern and angle pattern),
- butterfly,
- rotary plug (eccentric, spherical),
- ball, and
- valves with cage trims.
Specifically excluded are the full bore ball valves where the product FpC exceeds 50 % of the rated flow coefficient. This third edition cancels and replaces the second edition published in 2000. This edition constitutes a technical revision. The significant technical changes with respect to the previous edition are as follows:
- predicting noise as a function of frequency;
- using laboratory data to determine the acoustical efficiency factor.