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How to install acoustic window in a two leaf wall?
Old 24th January 2019
  #1
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How to install acoustic window in a two leaf wall?

Hi, could you point to a drawing of how to install an acoustic window in a two leaf system? I have someone to build it and istall it and have a little understanding of how this should be. From what I understand:

A. Window should be decoupled, this meaning separated window frames in each leaf

B. Frames should touch themselves

But regarding this design I have another questions:

1. How do you manage the interior of the wall to not be seen through the window?

2. How do you fill the window with mineral wool to absorb the resonance?

3. How would you hold the mineral wool to the sides of the window, top and bottom?

4. How do you know how many material you need in order to avoid humidity? If I understand correctly, a single frame window will have to control humidity only in the window cavity... With decoupled window we must control humidity of the whole wall?

5. How do you place this material into the wall or window?

Thank you!! =)
Old 24th January 2019
  #2
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Control Room Windows


Follow the info from the first link for isolations sake and calculating glass thickness. The following will show construction methods. You can also use fabric instead of acoustic tile to bridge the gap and hide the void.


Building A Control Room Window (HSR May 84)
Old 25th January 2019
  #3
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Quote:
Originally Posted by Jason Foi View Post
Control Room Windows


Follow the info from the first link for isolations sake and calculating glass thickness. The following will show construction methods. You can also use fabric instead of acoustic tile to bridge the gap and hide the void.


Building A Control Room Window (HSR May 84)
Thank u!!! the second link is very useful.. I can see everything... Any ideas of how thick should a glass be in order to match the density of a 15cm brickwall?

My second leaf is 3 layers of 5/8 gymsum board mounted on a 2x6 stud filled with mineral wool... From what I read, my glass in this leaf should be at least 5/8, am I correct?
Old 26th January 2019
  #4
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Im not an expert, and would feel better if one could chime in on this, but according to IR-586 (linked in this thread Backyard Concrete Block Studio (to fill or not to fill) ) concrete bricks 140mm thick will have a mass around 240-300 kg/square meter. 12.5mm drywall is around 8kg/square meter according to What is the density of Gyproc plasterboards?

So if glass is 3 times as massive as drywall 12.5mm of glass should be around 24kg/square meter. So you would need glass at least 125mm thick to match a brick wall. That seems rediculous to me, so theres got to be another factor to determine. Like i said, hopefully an actual expert can help with this one. Good luck!
Old 26th January 2019
  #5
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Quote:
Originally Posted by Jason Foi View Post
Im not an expert, and would feel better if one could chime in on this, but according to IR-586 (linked in this thread Backyard Concrete Block Studio (to fill or not to fill) ) concrete bricks 140mm thick will have a mass around 240-300 kg/square meter. 12.5mm drywall is around 8kg/square meter according to What is the density of Gyproc plasterboards?

So if glass is 3 times as massive as drywall 12.5mm of glass should be around 24kg/square meter. So you would need glass at least 125mm thick to match a brick wall. That seems rediculous to me, so theres got to be another factor to determine. Like i said, hopefully an actual expert can help with this one. Good luck!
I was thinking the same! I don´t even think I have seen a glass that thick in my life! Just to add a note... my whole wall assembly is 40cm thick and planing to use a decoupled window using the two leaf system sinche I have read is best
Old 26th January 2019
  #6
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Jason is correct.

What I suggest is investigating local glass prices and look the thickest before a significant price increase by thickness. 5/8 being the minimum.

Andre
Old 26th January 2019
  #7
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Quote:
Originally Posted by avare View Post
Jason is correct.

What I suggest is investigating local glass prices and look the thickest before a significant price increase by thickness. 5/8 being the minimum.

Andre
Dang, thats amazing, i figured i had to be missing something. Would acryllic be a better alternative? I know those giant aquariums use really thick acryllic. How do designers add windows when high levels of isolation are needed?
Old 26th January 2019
  #8
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Quote:
Originally Posted by Jason Foi View Post
Dang, thats amazing, i figured i had to be missing something.?
Why?

Quote:
Would acryllic be a better alternative? ?
At the risk of sounding repetitive, why? Acrylic has half the density of glass. It is lighter than concrete.


Quote:
How do designers add windows when high levels of isolation are needed?
By matching the design TL. Galaxy Studios designer (the great Eric Desart) reduced the specification for a control room window to be able to use the thickest glass made in Europe. I think that was 150 mm thick glass that was used.

Andre

Last edited by avare; 26th January 2019 at 10:52 PM.. Reason: Corrected HTML
Old 26th January 2019
  #9
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Mostly the cost involved with using 150mm thick glass. It must cost a fortune. I was just hoping there was a trick, or something i was missing somehow.
Old 28th January 2019
  #10
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Quote:
Originally Posted by Jason Foi View Post
Mostly the cost involved with using 150mm thick glass. It must cost a fortune. I was just hoping there was a trick, or something i was missing somehow.
Yeah I was hopping another way to turn this around too. Hopefully the airgap in my Wall Will increase the soundproof… I´m planning use two leafs of 5/8" one of them laminated with an air gap of 40 cm... Hope this Works well
Old 13th February 2020
  #11
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Northward's Avatar
Quote:
Originally Posted by avare View Post
Galaxy Studios designer (the great Eric Desart) reduced the specification for a control room window to be able to use the thickest glass made in Europe. I think that was 150 mm thick glass that was used.

Andre
They are 11cm thick IIRC.

And sadly their behaviour wrt to heat differentials were not properly inquired, so in the LR they broke. Still the broken ones in the there I believe - at least it was the case last time I was there, which was quite a while ago.

There is no danger or anything, it's all hairline cracks, but too costly to change them.

When heat differentials can be important, you must to somehow ventilate the air gap between glass layers or risk facing such issues. Which also means you need access to clean...
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