Calculating the noise level from a compressor

[silver1]

Hi guys

I am designing a Submerged Aerated Filter plant for use in the wastewater industry, but, I do have a problem with noise coming from the compressor units.

The noise level at site boundary of a compressor unit enclosed within a GRP unit is around 55db. On site, the background noise level is very low (> 35db). The client standard I am working to states that during normal operation the noise level should be 10bd below background noise.

Taking the background noise to be 35db and the nearest house to be 100m away, what set of calculations if any or method do I need to adopt to reduce the level as per client standard requirement?

Silver1 (Mech)

 

[MikeyP]

The answer usually is to enclose the unit in a case that is as massive and airtight as is feasable. To approach anywhere near 30dB attenuation (a big ask) that means some sort of masonry enclosure, double or triple skinned.

M

 

[JP0506]

Just be aware compressors, especially screw type (airends) are already encased in a specially designed casing. These are usually set up in a way to allow maximum air flow through the unit for cooling and any changes to this will affect the economics and life of the compressor. Instead of totally enclosing the unit you may be better off having a series of deflectors breaking the sound up and deflecting it possibly upwards.

JP

 

[Strong]

If your target sound pressure level is 25 dB at 100 meters, then the sound power level would have to be 73 dB re: 10E-12 watts. The sound pressure level (assume small source size) at 3 meters would be about 55 dB or 65 dB at 1 meter. I suggest you work in third or full octave frequency bands, and I assume your final overall value to be A-weighted. The criteria is very strict (perhaps unrealistic), so you have a lot of noise control work to do.

Walt