Noise is associated with vibrations that can damage the valve. Noise is usually associated to high outlet flow velocities which imply erosion issues. So when sizing a control valve, noise emission must be taken into account. For saturated steam applications, you can consider, as rule of thumb, 0.3 Mach as the threshold steam velocity above which noise level is not acceptable.
Take a look at the attached paper for further info.
There are Occupational Health and Safety considerations around noise levels in valves depending on whether workers are present in the area or not.
Also, while noise itself is not necessarily a problem, high noise levels indicate large pressure drops which can cause a lot of wear and tear on valve trim. If you have not already, you might want to talk to the valve supplier about this.
We have to deal with noise issues in valves all of the time, where we specify steam pressure reducing valves for district heating applications here in NYC. It turns out that for large flow rates the typical noise calculations show over 90dBa from the valve. If the valve is sized correctly with the right materials there is NO ill effects to the valve, these valves are designed for this type of pressure drop. It is the velocity in the valve that creates the drop in the first place, and noise is an unavoidable result.
However, as you can imagine, in a non-industrial setting, it gets LOUD. Normally the specification is for less than 80 dBa.
So, we use noise reduction techniques. There are valve trim options to mitigate the noise at the valve source, or orifice plates after the valve to break up the pressure drop to reduce the noise and also muffler devices after the valve that absorb the noise.
