AlphaPyramid™ Polyurethane Acoustical Foam

Product Questions & Comments (5 items)

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• Just wondering how the absorbtion coefficient is over 1 for this foam. Your page states that the absorbtion of this material ranges from .70 to 1.05

  Johann D'Mello - Student

  30 Positive

• Johann, thanks for the question. It's a great one. We do have many products listed as having a NRC of 1.05, and we do realize this is confusing and, well ... seems impossible. There is an explanation though. The 1.05 figure comes directly from lab tests, so we don't alter it when we post it to the Web site. These lab results indicate NRC ratings of 1.05 because they test one sheet of foam at a time, which means the edges (created by the depth of the sheet) are exposed. This creates absorptive surface area beyond the sheet's face. The 1 indicates the face (the only exposed area if many sheets are positioned tightly together) will absorb 100% of the noise, and the extra .05 shows the tests found more absorptive surface area (the edges) that could absorb noise if there was any left to absorb.

  Eric Peters - Acoustical Solutions, Inc.

  19 Positive

• NRC ratings are basically a number of efficiency in absorption, so how can something be greater than 100% efficient? Very good question, and heres the answer: They are giving a 3 dimensional object a fictional 2 dimensional number. Since acoustical computer models for a room are already in 3D, its easier to program slightly impossible 2D numbers onto a 3D wall, than it is to model a 3D thing in 3D space. As a convention though, the NRC ratings have worked their way into being the standard measurement for acoustical absorption. We do have tests showing the Sabins. If anyone is interested, please contact me at mdb@acousticalsolutions.com

  Matt Boughan - Acoustical Solutions, Inc.

  10 Positive

• We used some acoustic foam to try and reduce noise emitted by one of our industrial rotating saws by lining the interior of the guard enclosure with the foam. This significantly reduced the noise from 101 db to 89 db. We would like to continue to line our enclosure with the foam however we are not sure which type would be best. Could you please help us out with this. Thanks for you time!

  Diane Berniquer - Formica Canada Ltd

  0 Positive

• Diane,

  Hi there, thats a really great result for using foam! Generally its used for reducing echoes only, but there are instances where reducing the reflection points can yield a significant reduction in sound from a given testing location. Its very hard to predict this type of result, I have found that the only reliable way to find out if it will work or not is just to try it, and thats what you have done, and Im glad to hear it worked out so well for you! My recommendation would be to choose a foam that is the same overall thickness as the foam you used, or thicker if you have room. I would also recommend using only Class A fire rated Melamine foam for this. You may want to check the fire rating of the foam you currently have, if its not Class A fire rated you may run into trouble. Im not sure of the thickness you have, but a good catch all foam for this would be the Sonex Classic in Melamine, or Mod# SOC-2 in either white or light grey.

  URL: http://www.acousticalsolutions.com/123~sonex-classic

  Feel free to contact me if you have any further questions, thanks! mdb@acousticalsolutions.com or 1-800-782-5742 ext. 11

  Matt Boughan - Acoustical Solutions, Inc.

  0 Positive

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