Single Leaf Study? Paper?

[avare]

Originally Posted by John White

Does anyone know a paper with reports concerning transmission loss of single leaf partitions? I am very interested to know how a single leaf compares to wall assemblies such as the different configurations in IRC-761.

I know there is the Mass Law equation [ R= 20 log (fm) - 47 dB], but evidently that applies to limp mass partitions. Then one must include the elasticity (Young's Modulus?), but quite frankly it's over my head.

In particular, I'd like to know how favorably a single leaf partition compares to a standard two leaf assembly with respect to how a dual leaf wall typically has a coincidence (edit- no, a resonance) in the low frequencies.

NRC is your friend. Look at IR 818 text page 73 for starters.

Andre

[Sebg]

JW, how many examples do you want? IR-586 has single leaf masonry walls, with and without added plasterboard over a cavity, attached via various means and with/without infill. IR-811 also has some test data for floor layers only, ceiling layers only.

[John White]

Thanks Andre,

Unfortunately I was hoping for more examples like the one on page 73. Specifically, tests with one layer of gypsum, two layers, mdf, etc. The remaining tests were of more typical mass-stud-mass assemblies.

PS Great tests BTW. Some very high losses on some of the walls. Must be from the vinyl siding.

[John White]

Sebg,

Yes, I should have been more specific originally. As I've written subsequently, I am currently more interested in single partitions of DW for starters.

It may not sound realistic in a build, yet if the data presents itself favorably, I can see a use.

The only study I ran across in this regard was single wall partitions in order to show the effects of various amounts of insulation on TL.

[jhbrandt]

Originally Posted by John White

.....Some very high losses on some of the walls. Must be from the vinyl siding.

Good one John!
Cheers

[avare]

Originally Posted by John White

Sebg,

Yes, I should have been more specific originally. As I've written subsequently, I am currently more interested in single partitions of DW for starters.

The test I refered to uses MDF. Mass is mass.

Andre

[John White]

Disregard the following. Question in next post.

That example was OSB, but thanks, I think I understand:

So if I have a 50Lb sheet of OSB that obtains 25dB TL at 1000k-
Then I should have 50dB TL with a 100Lb sheet of MDF?
And 37.5dB with a 75Lb sheet of DW?

Is this linear with respect to frequency among different materials?

How does doubling or tripling the mass equate with doubling and tripling the number of sheets? I would imagine there is at least some greater loss due to friction or something similar.

[John White]

That example was OSB, but thanks, I think I understand:

So if I have a 50Lb sheet of OSB that obtains 25dB TL at 1000k-
Then I should have 31dB TL with a 100Lb sheet of MDF?
And 28dB with a 75Lb sheet of DW?

Is this linear with respect to frequency among different materials?

How does doubling or tripling the mass equate with doubling and tripling the number of sheets? I would imagine there is at least some greater loss due to friction or something similar.

[avare]

Originally Posted by John White

That example was OSB, but thanks, I think I understand:

So if I have a 50Lb sheet of OSB that obtains 25dB TL at 1000k-
Then I should have 31dB TL with a 100Lb sheet of MDF?
And 28dB with a 75Lb sheet of DW?

Is this linear with respect to frequency among different materials?

How does doubling or tripling the mass equate with doubling and tripling the number of sheets? I would imagine there is at least some greater loss due to friction or something similar.

It is fairly linesr in the TL increases by 6 dB per doubling of mass. There is minimal losss due to frcition between the layers. This type of loss is what Green Glue does.

Andre

[jhbrandt]

Agreed, but anymore I only count on getting about 5db per doubling of mass. It's all about the mass, John, when considering single partitions. I subtract the 1db accounting for real world issues.

I have a 'quickie' calculator for Mass Law in my Reflections Boundaries Mass excel calulator on my publications page.... line 80 on the second tab.

Cheers,
John

[avare]

Originally Posted by jhbrandt

Agreed, but anymore I only count on getting about 5db per doubling of mass. It's all about the mass, John, when considering single partitions. I subtract the 1db accounting for real world issues.

+1.

Massively,
Andre

[John White]

Originally Posted by avare

It is fairly linesr in the TL increases by 6 dB per doubling of mass. There is minimal losss due to frcition between the layers...
Andre

Great. Thank you.

I have found the "Modulus of Elasticity" for a few materials. I'll try to post a few examples using this and just mass for mass in the next week or so. Just as an exercise for me and interest to any one. I'll use 6dB for doubling of mass as this is theoretical anyway, but noted.