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Sound Attenuation & Thermal barriers Post New Topic | Post Reply
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Rob Granger
Posted: Sep 28, 2010 05:34 PM
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Sound Attenuation & Thermal barriers
A client wants his compressor room in an industrial setting spray foamed to cut down on the noise. If I spray a thermal barrier on the OC foam how much will the sound attenuation properties be reduced by? Any suggestions?
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Ivan Pauliuchenka
Posted: Sep 29, 2010 06:18 AM
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STC rating will not reduce if something it will add a point or a half to overall STC (sound transmitting class). 4" of open cell has STC 38-42 by doubling the amount you get just extra 6 STC points at the most. One of the options - if he is really annoyed by the noise - double sheetrock on the outside with layer of sound absorbing glue (`greenglue`) and open cell inside with thermal cote for CODE. Make sure every little hole is sealed. I had a project on sound proofing Irish pub build in 1880`s. Had to soundproof for the owner to get his license back. He hired acoustical engineer who was trying to make owner to silicone every hole in his 3,000 sq ft attic and then putting sound batts from Owens Corning. I had to prove that OC has same or better properties - so I did, and I have some info on this. Foam still does better job in absorption of sound and vibrations. Cellulose is still better - mixed with OC foam over or under - even better. By adding `loose mass` to your wall system will increase the STC rating (concrete blocks with sand, heavy silicone glue between layers of Sheetrock, cellulose on to of the OC and so on) . |
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mason
Posted: Sep 29, 2010 08:18 AM
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Thanks for helping out VIP marine, To make it simple, open cell sprayfoam helps block sound by sealing air leaks that can carry the sound from one room to the other. But, it is not as good a sound absorbing material as cellulose. Still, open cell foam is much better sound absorber as closed cell foam. The compressor will be making sound that is carried through the air and vibration type noises that are transmitted through the wall assembly materials. So, I agree with VIP's recommendation of adding an additional wall with sound absorbing material between it The more walls and sound absorbing material you can put between the rooms, the better at stopping the sound from going from one room to the other. |
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Rob Granger
Posted: Sep 30, 2010 05:25 PM
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Thanks for the information but the main portion of my question remains unanswered. If I spray a Thermal Barrier on 1/2 lb foam how much will the TB reduce the attenuation properties... |
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Posted: Sep 30, 2010 09:40 PM
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yes,,hey man,,im not sure that those "studies" are out there... in my humble hillbilly opinion,, useing the process of grey matter stimulation,,, i'm not sure it would effect the stc or nrc much if any.. now there may be a case for slightly,,real slight reduction in the stc due to the "rigid nature" of the coating,,but in my limited,,but increasing,,exposure to the coating TB/IB products im not sure that this coating will change things much.. im thinking vibrational transmition,,but this film layer is thin,,so im thinkin,,not so much.. fat chance in hades that the coating manu's will poney up for a "study" for this kind of data,,its all about the numbers,,and they care about TB and IB not sound,,it's market share.. be careful what you represent our wonderful product can deliver,,,sound control is an "ex-wife",,,and compressors make a boat load of sound,,not includeing the vibrational transmission even in an "vibrational isolated" installation... vip made a great suggestion...isolation will reap rewards... |
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mason
Posted: Oct 01, 2010 08:07 AM
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I agree with foamdude, I doubt the thin layer would accomplish much |
