Common Gas Flow Resistivity numbers.

[DanDan]

Thanks Andre. It is odd that they put the figure right on the front page of a general info sheet, yet it is relatively meaningless.
I suspect that 5KRayls is the GFR of the lightest CIB, thus the other two are greater than.
I will ask them for clarification now that you have calibrated my thoughts.

Tuned, DD

[DanDan]

Thank you Victor. I am sure you are aware but for other readers, one of the big reasons for my interest in CIB, is the DIY VPR possibilities over at My Experiment with a Metal Panel Absorber
DD

[avare]

Originally Posted by Victor_Stoian

according to mr. Fischer from Caruso:
ISOBOND WLG040 (20kg/m³) has about 5kPa*s/m²
ISOBOND WLG035 (45kg/m³) has about 12kPa*s/m²

I am not Dan, but thank you for the information.

Andre

you're welcome!

[tlindaas]

Detailed info on air flow resistivity, absorption coefficients and density from several manufacturers in Norway, Sweden and Germany in these 3 posts:

Air flow resistivity, absorption and density for isolation products in Norway
Air flow resistivity, absorption coefficients for isolation products in Germany
Air flow resistivity for Isover Sweden

[DanDan]

Thank you for all that great work tlindaas.
May I ask a favour? Could you edit or do a new post, copying and pasting all of that info into one post here. I would be more than willing to do this for you if you wish.
My hope in starting this thread was to gather as many GFR figures as poss in the one convenient place.

I or someone else perhaps may collate some of the info sometime.
e.g present the range of GFR's for 48KG and 100KG Glass



Best, DD

[tlindaas]

No problem, take whatever you need from those threads :-)

[DanDan]

I was taking a look at the links while you were writing. There is an enormous amount of data there. I will leave it alone for the moment, but thoroughly recommend those links. Again, thank you.
Amongst the mass of data we have this little gem...
Air flow resistivity ----------------------------: 5 kPa*s/m2 ------10 kPa*s/m2 ----- 20 kPa*s/m2 - ---30 kPa*s/m2 ------40 kPa*s/m2 ----- 50 kPa*s/m2
Rockwool stone wool products: ------------- : 9-31 kg/m3 ----- 24-49 kg/m3 ----- 36-75 kg/m3 ---- 47-98 kg/m3 ------ 56-120 kg/m3 --- 64 -130 kg/m3
Isover stone wool products: ---------------- : 27-40 kg/m3 --- >50 kg/m3 ---------------------------------------------------------------------------------------
Unspecified Nordic stone wool products --- : ------------------- 32-37 kg/m3 ----- 38-52 kg/m3 ---- 53-65 kg/m3 ----- 70-80 kg/m3 ----- 80-90 kg/m3
Isover glass wool products: ---------------- : 9-18 kg/m3 ----- 15-30 kg/m3 ----- 27-45 kg/m3 ---------------------------------------------------------------
Unspecified Nordic glass wool products --- : ------------------- 13-27 kg/m3 ----- 33-45 kg/m3 ---- 47-58 kg/m3 ----- 65-75 kg/m3 ----- 75-85 kg/m3

DD

[DanDan]

Thanks to Kaleido.

Isover Piano Ljudskiva
Density: 13-15 kg/m3
Air Flow Resistivity: 7 kPa*s/m2

Isover Cleantec Plus
Density: 35 kg/m3
Air Flow Resistivity: 7 kPa*s/m2

Isover UNI-skiva 36
Density: 16-19 kg/m3
Air Flow Resistivity: 13 kPa*s/m2

Isover UNI-skiva 33
Density: 20-35 kg/m3
Air Flow Resistivity: 18 kPa*s/m2

Isover Fasadskiva 31
Density: 50-60 kg/m3
Air Flow Resistivity: 55 kPa*s/m2

DD

[Mister Fox]

Here's another addition to your list:

According to several mails with the German firm e.m.o. e.K. (schaumstofflager.de), their BASOTECT material is made by BASF and has a flow resistence of 12,4 kPa*s/m²


Here's a quite from the mail:

According to BASF: The flow resistence of Basotect G as listed in DIN EN 29052 averages 12,4 kPa*s/m²

This would make it twice as effective as Rockwool (SONOROCK) of the German firm Rockwool.

Source link:
schaumstofflager.de
Panels are sold in 100x100 and 100x50 centimeter cuts. Custom cuts are possible, you just need to mail them. They are pricey however.


And a word of warning, they usually only go by material density, which they think is more important in acoustics than flow resistence.

[Jens Eklund]

Originally Posted by Mister Fox

Here's another addition to your list:

According to several mails with the German firm e.m.o. e.K. (schaumstofflager.de), their BASOTECT material is made by BASF and has a flow resistence of 12,4 kPa*s/m²


Here's a quite from the mail:



This would make it twice as effective as Rockwool (SONOROCK) of the German firm Rockwool.

What do you mean "twice as effective"?

[Mister Fox]

Sonorock has a flow resistence of about 6kPa, BASOTECT accorting to the mail about 12,4kPa.

So if I go by plain numbers, a rockwool slab with 5cm and 6kPa flow resistence is (in theory) half as effective as Basotect with the same thickness. Or the other way around: Basotect is (in theory) twice as effective at the same thickness as Rockwool (Sonorock).


Comparision:
http://www.stanleyhallstudios.co.uk/...1=50&v21=12400

In this math example, Sonorock actually goes lower in terms of absorption than Basotect. But Basotect has a coefficient of 0,8 at about 800Hz while Sonorock reaches the same value at about 1,2kHz.


Here is a comparision with 10cm thickness (about 4"):
http://www.stanleyhallstudios.co.uk/...=100&v21=12400

Here, Sonorock reaches down to about 400Hz at 0,8 (coefficient), while Basotect is effective down to circa 320Hz.


You decide what suits your needs better. Sonorock is however more affordable than Basotect at the same thickness over here. Then again, should I decide to build a barrier matt trap/resonator, I maybe opt for Basotect instead of Rockwool.

Like in this example:
Sound on Sound StudioSOS March 2006 Bass Trap

[Jens Eklund]

Originally Posted by Mister Fox

Sonorock has a flow resistence of about 6kPa, BASOTECT accorting to the mail about 12,4kPa.

So if I go by plain numbers, a rockwool slab with 5cm and 6kPa flow resistence is (in theory) half as effective as Basotect with the same thickness. Or the other way around: Basotect is (in theory) twice as effective at the same thickness as Rockwool (Sonorock).


Comparision:
Porous Absorber Calculator - Results

In this math example, Sonorock actually goes lower in terms of absorption than Basotect. But Basotect has a coefficient of 0,8 at about 800Hz while Sonorock reaches the same value at about 1,2kHz.


Here is a comparision with 10cm thickness (about 4"):
Porous Absorber Calculator - Results

Here, Sonorock reaches down to about 400Hz at 0,8 (coefficient), while Basotect is effective down to circa 320Hz.


You decide what suits your needs better. Sonorock is however more affordable than Basotect at the same thickness over here. Then again, should I decide to build a barrier matt trap/resonator, I maybe opt for Basotect instead of Rockwool.

Like in this example:
Sound on Sound StudioSOS March 2006 Bass Trap

The absorption properties of a porous material is determined by the flow resistivity and the depth of the absorber (and possible air gaps). A high flow resistivity does not automatically mean "better performance". Actually, if used at normal depths (about 200 mm or deeper, or you´ll just "EQ" the reflections removing the mids and highs as demonstrated by your examples); the opposite is true. Also, random incident values are not usually of interest since broadband absorbers used in studio design are primarily intended to absorb first order reflections and these arrive at specific incidence.

[Mister Fox]

If I go by your posted GIF example, the SONOROCK actually performs better at 20cm thickness compared to BASOTECT G with a higher flow resistence. It's the other way around at 10cm (here BASOTECT goes lower but has not such a high coefficient).

With all the data we have at the moment, we could in theory indeed find the right material for the right desired thickness of an absorber.

This is certainly interesting.

[DanDan]

It certainly is. There is a specific thread focussed on fibre and gap depth and density and GFR. Q 4 Avare
This thread here was born out of that. It is meant to be a growing list of GRF figures. People have found it difficult to get actual GFR's. Those that have succeeded have been kind enough to share in this dedicated thread.

DD