• If You Are Having Trouble Logging In with Your Old Username and Password, Please use this Forgot Your Password link to get re-established.
  • Hey! Be sure to login or register!

Ideas to silence an Air Compressor?

I bought an American Standard 3 ph 10hp. 175 psi four cylinder compressor on eBay for $1,100. The vendor was in the San Francisco Bay Area. Guaranteed to function. Ship via Northern Air Cargo. Told them slow boat to China. NAV did expedited shipping to the tune of +$3,200. Had to be air freighted out of Anchorage to Platinum. I complained... they’d already made a bundle off me that year resulting in a reduction to zero on the freight bill. Turned out the compressor head was toast. Bought the parts and rebuilt it. Vendor paid for my labor and parts... in the end the compressor cost me $221.00

Installed the compressor in the basement. Uses 110 vac control voltage. I could install a plane old light switch up stairs in the main shop area to turn it on and off.. as it is I have walk to the compressor to turn it on... if we had a switch upstairs I wouldn’t be keeping a close eye on the oil level.
 
Back from the Copperstate Fly-in and worked on the compressor enclosure today. It's ready to slide the compressor in and bolt it down and run the plumbing. I'll use rubber isolator feet and see how that does reducing the vibration. The enclosure has 7/16" OSB on the outside, framed in 2x4's. The inside is 5/8" sound board and cavity is filled with rock wool all around, including the ceiling. Working inside, it is kind of strange how the sound is just dead. The A/C condenser that I use will be on top. There is an opening on the side for forced air in, and opening on the top for exhaust. Both will use a sound box to muffle the sound around the openings. I found the info on the muffler boxes on a site that specializes in this sort of set up. I haven't started on the door yet but it will be about the same construction.

Marty

IMG_6288.jpg IMG_6293.jpg
 

Attachments

  • IMG_6288.jpg
    IMG_6288.jpg
    59.2 KB · Views: 157
  • IMG_6293.jpg
    IMG_6293.jpg
    43.4 KB · Views: 179
I finished up the compressor enclosure. I mounted the fan on the side and added a power strip as a switch. I downloaded a decibel meter and did some testing. With the door open and compressor running, the meter read 91 decibels. With the door closed, same distance away, the meter read between 76 and 80 decibels. Lets say about 15 decibels reduction. What does this mean? I don't know, but I can carry on a conversation in front of the enclosure when the compressor is running. I'm pretty happy with the reduction in noise. A few pictures below.

Marty

IMG_6328.jpg

IMG_6330.JPG

IMG_6329.jpg
 

Attachments

  • IMG_6328.jpg
    IMG_6328.jpg
    75.5 KB · Views: 181
  • IMG_6330.JPG
    IMG_6330.JPG
    104 KB · Views: 184
  • IMG_6329.jpg
    IMG_6329.jpg
    66.8 KB · Views: 166
15db means you've halved the acoustic power 5 times. So you're down to 3% of the previous noise. Ears have AGC so it may not seem that way. A noise app uses your uncalibrated smartphone mic, but the 15db difference should stand, even if you don't really know your start and end measurements.
 
15db means you've halved the acoustic power 5 times. So you're down to 3% of the previous noise. Ears have AGC so it may not seem that way. A noise app uses your uncalibrated smartphone mic, but the 15db difference should stand, even if you don't really know your start and end measurements.
Thanks for the numbers. I knew it was something like that but I wasn’t sure the numbers. I still have to build a baffle at the exhaust from the enclosure; that opening is right over the pump. I may also baffle the squirrel cage fan some to get the sound down a bit more. The more reduction the better.
Marty
 
I built the last of the baffles for the compressor enclosure. I made a sound baffle for the exhaust on the top of the enclosure. I have to say, to my ear, this made a huge decrease in the sound. The meter showed between a 3db and 5db reduction. The highest I recorded was in the 90-96db range with the compressor running and the doors open. With it running as it stands now, I'm getting 71-73db. The air coming out of the top exhaust is only slightly warm, motor is only warm to the touch. The pump is just as hot as before where the air exits the pump at the copper pipe. Specifications for compressor calls for 12" minimum from back wall; my set up is 18" from back wall. Air inside the enclosure after a good long run of the compressor does not seem to be any different than the temps outside the enclosure. I think having a cooler for the air outside the enclosure helps with temperature control. All in all, I'm pretty happy with the results. I have a painting seminar coming up in here in March; this should allow me to actually talk and be heard during spraying. I posted a picture of the sound baffle I installed on the top for the exhaust.

Marty

IMG_6331.jpg
 

Attachments

  • IMG_6331.jpg
    IMG_6331.jpg
    67.7 KB · Views: 110
I built the last of the baffles for the compressor enclosure. I made a sound baffle for the exhaust on the top of the enclosure. I have to say, to my ear, this made a huge decrease in the sound. The meter showed between a 3db and 5db reduction. The highest I recorded was in the 90-96db range with the compressor running and the doors open. With it running as it stands now, I'm getting 71-73db. The air coming out of the top exhaust is only slightly warm, motor is only warm to the touch. The pump is just as hot as before where the air exits the pump at the copper pipe. Specifications for compressor calls for 12" minimum from back wall; my set up is 18" from back wall. Air inside the enclosure after a good long run of the compressor does not seem to be any different than the temps outside the enclosure. I think having a cooler for the air outside the enclosure helps with temperature control. All in all, I'm pretty happy with the results. I have a painting seminar coming up in here in March; this should allow me to actually talk and be heard during spraying. I posted a picture of the sound baffle I installed on the top for the exhaust.

Marty

View attachment 41620

Got any shag carpet lying around?

Glenn
 
Thanks John, thats a great the chart. Guess I got the sound down to a pretty manageable level. Maybe now I'll hear my wife a bit better ;-)
Marty
 
You can always leave the enclosure door open.....:wink:
MSHA (mine safety health admin) always held the threshold at 85dba for 8 hours. Anything over that and we had to start limiting hours of exposure. I'd say with the short bursts of compressor noise, you're way below any problem level.
JH
 
Back
Top