Noise Reduction
Noise Reduction
(OP)
We use "modified" compressors to pump our process gasses through the plant. We have about 22 compressors that makes quite a lot of noise. ~ 130dB for one, then you add about 6dB for every compressor, thus in total more or less 256dB.
We definitely need to provide ear protection for our operators. An we consulted a acoustic engineer and he said that the only way to shield noise is by surrounding the unit that makes the noise with mass & density (concrete, steel, ect) and that putting soft tissue on the walls will, if that much, only absorb ~6dB in total.
Please comment!
If anyone knows about an alternative way to reduce noise instead of surrounding our compressors with cement/steel or to put them underground, I will appreciate your input.
We definitely need to provide ear protection for our operators. An we consulted a acoustic engineer and he said that the only way to shield noise is by surrounding the unit that makes the noise with mass & density (concrete, steel, ect) and that putting soft tissue on the walls will, if that much, only absorb ~6dB in total.
Please comment!
If anyone knows about an alternative way to reduce noise instead of surrounding our compressors with cement/steel or to put them underground, I will appreciate your input.





RE: Noise Reduction
256dB sounds impossibly high, but even 130bB or above is serious noise. I think you should review your noise calculations including your interpretation of the attenuation estimates supplied by your acoustic engineer. A plot plan with actual noise survey data is the best way to capture the distance impact of noise in the work area, a factor which you don't mention when citing your noise levels. You may be better off than you think once your engineering controls are installed.
In the USA you would be required by OSHA code to implement some engineering and administrative controls- hearing protection is personal protective equipment and cannot alone bring you into compliance.
Generally you only have two noise control choices at the compressor itself, lag the compressor directly or put it inside an enclosure. For multiple units an enclosure is usually more economical. It has not been my experience that these enclosures are solid concrete, but rather a metal frame with panels designed for noise control. On the otherhand, even a solid concrete barrier wall would be a welcome relief if the situation is as bad as you describe.
best wishes,sshep
RE: Noise Reduction
When you use noise enclosures, note that you also have to provide forced ventilation, gas detection in order to protect against explosions (assuming you have a flammable gas in your plant).
RE: Noise Reduction
I guess burying compressors underground is not very cost-effective and makes maintenance a pain in the butt, but before discussing preventive measures futher, go out there and collect more detailed data.
RE: Noise Reduction
As suggested here and in other replies you must consider geometry first then attenuation. I do not doubt however that your compressors are not too noisy. There are many ways to attenuate noise and there are some very effective commericial products. Depending on the frequency of the noise concrete and/or steel can be as much a transmittor of noise as an attenuator. No simple answers with noise engineering. However the commerical products do work and you can get significant reduction using this or adding insulation lagging to the source. If possible the easiest way to significantly reduce the noise may be to modify these "modified" compressors however.
good luck.
RE: Noise Reduction
Can you comment on the use of white noise? The alternative would be lagging (and personel protection for the operators).
If white noise is a suitable solution, it would make communication on the process floor much easier.
How advanced/effective is white noise apparatus currently?
RE: Noise Reduction
104 dB sounds like a much more reasonable number. I guess most chemplants solve the local problem (for the operators and maintenance people) with earplugs. That of course provides no solution for the surrounding communities if you have a problem with those. I wouldn't be able to advise further on that, I'm really not an acoustic expert.
RE: Noise Reduction
RE: Noise Reduction
When I look at the description of white noise on http://science.howstuffworks.com/question47.htm , I don't think this will help you. You can mask a specific noise by adding noise at other frequencies, but you cannot make it disappear... It will not make communication on the process floor easier as you suggested.