Author Topic: MLV layers--not cumulative?  (Read 1822 times)

Leedo

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MLV layers--not cumulative?
« on: September 15, 2011, 03:31:17 AM »
Greetings--this is my first post here and there's some great info on this forum.  Reason for my post: I just want to make sure I understand the following concept correctly:

When it comes to layers of Mass-Loaded Vinyl, each additional layer does not mean that the STC reduction is cumulative.  Is that accurate?
 
In other words (for example), if one layer of MLV provides an STC reduction of 25 db, a 2nd layer of MLV would not mean a total STC reduction of 50 db--the STC reduction of the two layers together would be somewhat less than that.
 
I've read a few posts here on the subject and just want to confirm.  Thanks very much.




Randy S

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Re: MLV layers--not cumulative?
« Reply #1 on: September 15, 2011, 03:10:53 PM »
Yes you are correct, MLV and all principles of assemblies STC value are NOT cumulative.

So in order to understand how that value works would entirely depend on the way the material is installed in an assembly.

ex. 1 layer 1/8" MLV =STC 26 in a limpid application.
     2 layers 1/8" MLV = STC 36 in a limpid application. This value based on same side application (back to back), you can increase the actual field performance by separating (both sides of framing).

However, 1 layer in a rigid assembly =STC 13

Now also keep in mind that these values are based on the Average range of frequencies so the field results will vary based on frequencies generated.

Feel free to give me a call if you would like to get into the particulars.
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Randy Sieg

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