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Common Gas Flow Resistivity numbers. Studio Monitors
Old 29th June 2011
  #1
Gear Guru
Common Gas Flow Resistivity numbers.

Over time I have noted that various posters have discovered actual Gas Flow Resistivity figures for commonly used materials.
I always meant to collect and present them but didn't get it together.
So.
If you know the GFR of any fibre, please let us all know here in this thread.
Probably best to provide links a note as to where/how you get the number.

DD
Old 29th June 2011
  #2
Gear Addict
 

CSR Bradford. Australian products only, but it's a start I suppose.

http://www.bradfordinsulation.com.au...ign-Guide.aspx

download link on this page:
http://www.bradfordinsulation.com.au...-internal.aspx

Page 78. Glasswool and Rockwool.
Note that the figure for Quietel (130kg/m^3 Glasswool) is probably low.
Old 30th June 2011
  #3
Gear Head
 
laagman's Avatar
 

OC701. Anyone?

Can sheets of fiberglass from different brand, but with the same density, have different flow resistivity numbers?
Old 30th June 2011
  #4
Gear Addict
 

Yes.
depends on fibre diameter and no. fibres per unit volume.
Old 30th June 2011
  #5
Gear Addict
 

Quote:
Originally Posted by laagman View Post
OC701. Anyone?

Can sheets of fiberglass from different brand, but with the same density, have different flow resistivity numbers?
Even same brand, isover for one, but marketed in different countries may exhibit different GFR's because not manufactured at the same place.
Old 2nd July 2011
  #6
Gear Guru
Bump and

Found a few. Thanks to those who posted these elsewhere.
CSR Bradford (Australia) has published flow resistivity figures for some of its products.

Building Blanket (11kg/m^3): .. 5,600 mks Rayls/m
Multitel (18kg/m^3) .............. 15,300
Flexitel (24kg/m^3) .............. 16,200
Supertel (32kg/m^3) ............ 18,200
Ultratel (48kg/m^3) .............. 31,500

Isover E100 S (50Kg/m^3).......44000 mks Rayls/m
Isover E60 S (30Kg/m^3).........22000 mks Rayls/m

From the NASA study. OC703....27000 mks Rayls/m


On the Italian site there is an interesting software:
Software | Rockwool Italia S.p.A.
this is in italian but I think you can manage it....it's based on test measures made by the Engineering Department of the university of Ferrara.
Sadly it stops at 100 and only calculate the absorbtrion coefficients at the normal incidence, but it mention the specific Flow Resistivity datas of many of their products.....

DD edit, could someone with a PC please copy and paste that data or some of it, from that software?

DD
Old 2nd July 2011
  #7
Gear Addict
 

Isover IBR 300, available in most French DIY superstores, 300mm thick, is 10Kg/m3 and GFR is around 5000, pretty adequate for Superchunks (60x60x84 cm) and deep panels.
Old 2nd July 2011
  #8
Gear Guru
Homatherm

FlexCL ..... is between 43000 and 76000 Rayls/m

Seems like a very broad range.

DD
Old 2nd July 2011
  #9
Gear Maniac
 

from rockwool software

40kg/m3 = 14916 N s/m4
45kg/m3 = 17527 N s/m4
50kg/m3 = 20248 N s/m4
55kg/m3 = 23072 N s/m4
60kg/m3 = 25992 N s/m4
65kg/m3 = 29003 N s/m4
70kg/m3 = 32102 N s/m4
75kg/m3 = 35284 N s/m4
80kg/m3 = 38545 N s/m4
85kg/m3 = 41882 N s/m4
90kg/m3 = 45293 N s/m4
95kg/m3 = 48774 N s/m4
100kg/m3 = 52324 N s/m4
105kg/m3 = 55940 N s/m4
110kg/m3 = 59621 N s/m4
115kg/m3 = 63364 N s/m4
120kg/m3 = 67167 N s/m4
125kg/m3 = 71030 N s/m4
130kg/m3 = 74950 N s/m4
135kg/m3 = 78926 N s/m4
140kg/m3 = 82957 N s/m4
145kg/m3 = 87042 N s/m4
150kg/m3 = 91179 N s/m4
155kg/m3 = 95367 N s/m4
160kg/m3 = 99606 N s/m4
165kg/m3 = 103894 N s/m4
170kg/m3 = 108230 N s/m4
175kg/m3 = 112614 N s/m4
180kg/m3 = 117044 N s/m4
Old 3rd July 2011
  #10
Gear Addict
 

The Rockwool numbers refer to a density, not a given product kind (Alfarock, Alfasol, AlfaMur in France for instance), but are we sure that a Rockwool product, whatever marketing name it may have in a country, said to have such a density will really exhibit the mentionned GFR ?

At least those numbers can be used to run Porous Absorber Calculator and get some data, but how can we really be confident in that ?
Old 3rd July 2011
  #11
Gear Guru
Wide Goalposts

Thank you audioactive.
Here's a questionable graph which relates Density and GFR.
https://www.gearslutz.com/board/6528365-post17.html

I would guess that there is quite a wide variation of density and GFR even within the same batch. Light and fluff arrives pretty solid and dense in it's packaging. It expands when unpacked, and presumably contracts a little over time.
And look at those figures for FlexCL!

Someone had GFR's for a couple of Roksil densities. I hope they chime in.

Here is probably a good place to promote this relatively new Porous Absorption Calculator, thanks to Demetris.
Porous Absorber Calculator

And some more courtesy of Sebq

Bradford Rockwool Building Blanket 13000 mks Rayls/m (nominally 30kg/m^3 product)
Bradford FIBERTEX ™ 350 Rockwool 22000 (60kg/m^3)
Bradford FIBERTEX ™ 450 Rockwool 33000 (80kg/m^3)
Bradford FIBERTEX ™ 650 Rockwool 53000 (100kg/m^3)
Bradford FIBERTEX ™ HD Rockwool 70000 (120kg/m^3)

DD
Old 3rd July 2011
  #12
Gear Maniac
 

rockwool product names used in the software are

211, 213 (40kg/m3)
220, 214 (50kg/m3)
226 (60kg/m3)
225, 231 (70kg/m3)
590 (80kg/m3)
233, 234 (100kg/m3
520 (120kg/m3)
431 (155kg/m3)
750 (115kg/m3)
755 (145kg/m3)
251 (180kg/m3)

not sure these models are available outside italy tho..
Old 4th July 2011
  #13
Gear Addict
 

DD,

I have enough issues with people misspelling my name, let alone my forum moniker...

And I posted the link to all the published CSR Bradford data in the second post in this thread.

Sebg

You can call me Sebastian as well.
Old 4th July 2011
  #14
Gear Guru
Jeez

Sorry Sebastian, I am a little Dilexic....

It's just a style thing but I much prefer if someone posts the actual information of interest rather than a link to where to find it. Ditto with opinions. It may be tedious for us to post similar answers again and again, but it is a tad antisocial to link to a link to a previous post for instance.
In this case the desired info was at the end of an 80 page book! I know, there is a list of contents....

However, what a book. On a quick scan this is way better than most text books and it seems to cover many if not all aspects of Acoustics and Noise control. This is one for Torea's collection in the sticky.
Nice one.

DD
Old 4th July 2011
  #15
Gear Addict
 

Ah well, I was guilty of being lazy. I had posted the Rockwool data and some of the Glasswool data in other posts and didn't want to go looking for them again. Plus the book has some useful info in it, including tests on attenuators, lined ducts and absorption coefficients so it was worth linking the whole document I thought.
Old 4th July 2011
  #16
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boggy's Avatar
Quote:
Originally Posted by Sebg View Post
.........Plus the book has some useful info in it, including tests on attenuators, lined ducts and absorption coefficients so it was worth linking the whole document I thought.
Thank you very much! heh
Old 4th July 2011
  #17
Gear Addict
 

Quote:
Can sheets of fiberglass from different brand, but with the same density, have different flow resistivity numbers?
additionally to the reasons Sebq mentioned, some products, especially those designed to be used in ceilings may contain more oil (dust binder), which affect gas flow resistivity.
Old 6th July 2011
  #18
NLP
Gear Addict
 
NLP's Avatar
 

Knauf Slovenia:
rockwool 30kg/m3 - 5kPA s/m2
rockwool 50kg/m3 - 10kPA s/m2
rockwool 80kg/m3 - 15kPA s/m2
DP-3, DP-5 - Ve
Old 21st July 2011
  #19
Gear Maniac
 
aackthpt's Avatar
 

from Acoustics Forum • View topic - Membrane Abosrber Calculator (Excel) posted by Terry Montlick:
Fibertex 350 Rockwool 2.2 x 10^4 Rays/m
Fibertex 450 Rockwool 3.3 x 10^4 Rays/m
Fibertex 650 Rockwool, has an acoustic resistivity of about 50000 mks Rayls/m
Fibertex Hd Rockwool 7.0 * 10^4 mks Rayls/m
Fibertex Rockwool Building Blanket Plain 0.5 x 10^4 mks Rayls/m
6000 mks Rays/m is roughly the resistivity of a fluffy fiberglass batt.

OC 703 has a resistance of 600 mks Rayls/inch (about 23600 mks rayls / m)
OC 705 has a flow resistance of 770 mks Rayls/inch (about 30000 mks rayls / m)
Bradford Fibertyex 650 (same density as OC 705) is 1270 mks Rayls/inch (about 50000 mks rayls / m).

Air, on the other hand, has a characteristic resistance of 407 mks Rayls/m.

Glasswool Ceiling Batts 105mm 0.5 x 10^4 mks Rayls/m

(above from various posts, and http://www.bobgolds.com/AbsorptionCoefficients.htm
below from ir761)

glass fibre (G1) 89 mm batt 4800 mks rayls/m
glass fibre (G1) 65 mm batt 3600 mks rayls/m
glass fibre (G1) 150 mm batt 4300 mks rayls/m
glass fibre (G2) 89 mm batt 7900 mks rayls/m
mineral fibre (M1) 89 mm batt 12700 mks rayls/m
mineral fibre (M1) 65 mm batt 11400 mks rayls/m
mineral fibre (M2) 75 mm batt 16600 mks rayls/m
mineral fibre (M2) 40 mm batt 15000 mks rayls/m
mineral fibre (M3) 83 mm batt 58800 mks rayls/m
cellulose (C2) 90 mm blown 33000 mks rayls/m


Also contained is a graph (looks like Excel) of rockwool and fiberglass flow resistivity vs. density.


------------------------------------
From https://www.gearslutz.com/board/1920039-post32.html

Andre,

appreciate the info, hope they come back at you.
Isn't that M3 product quite close to OC 705? 705 has also got about 90-100 kg/m³

Here are GFRs (in kPa*s²/m²) for German products I could come up with. You can see the density by looking at the name. DP-3has about30kg/m³ for example.

"Heraklith Heralan" Rockwool:
DP-3: > 5
DP-4: ≥ 7
DP-5: > 7
DP-7: > 7
Dp-10: ≥ 20
DP-12: ≥ 25
DP-15: ≥ 25
(Knauf Insulation)


"Rockwool" rockwool:
Termarock 30: > 9
Termarock 40: > 12
Termarock 50: > 15
Termarock 100: > 43
(
Baushop.DE: 350.857 günstige Artikel,News auf Bau online - baustoffmarkt-online)


"Isover" Rockwool:
SP 120: ≥ 40
SP 150: ≥ 50
SP 180: ≥ 70


"HOMATHERM flexCL", made from cellulose, which has also good absorption coefficients:

about 70 kg/m³: 43 - 76
(
Saint-Gobain Isover G+H AG - mit dem Scout zum richtigen Dämmstoff)

Greets,
Jules

--------------------
From https://www.gearslutz.com/board/1921465-post39.html

I received a reply from Roxul re: GFR for their materials. The only material that they had data for was AFB. AFB is 2.8 pcf and has airflow resistivity at 3" of 16,600 mks rayls/m and for 1.5" 15,000 mks rayls/m.

Andre

----------------------------
https://www.gearslutz.com/board/1958094-post41.html
OC responded with the following data:

701 8,300
703 16,00
705 30,00

Andre


------------------
Earlier in the same thread above, though (post #2) Andre stated: 703 has a gas flow resistance of (depending on the phase of the moon when OC publishes data) between 16 000 and 24 000 .
-----------------

Obviously, I'd been thinking to create a cache of flow resistivity values myself, and did some searching and stashing at one time. I think it would be valuable for everyone if as many values as possible (also possibly links to software or tools to extrapolate values) were to be collected and hosted on a webpage, similar to the Bob Golds absorption page.

Regards,
John

Last edited by aackthpt; 21st July 2011 at 09:40 PM.. Reason: Improve politeness
Old 22nd July 2011
  #20
Gear Guru
Excellent

Great stuff, thanks. Keep em coming.
DD
Old 23rd July 2011
  #21
Lives for gear
 
avare's Avatar
 

I thought that you are aware of the thread with the gas flow resisitivity values in it. If not, I apologize for not mentioning it in this thread.

This thread is a great idea. I hope it is successful!

Andre
Old 3rd August 2011
  #22
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avare's Avatar
 

I just received an email from Roxul Canada regarding gas flow resistivity values for their products. The reason given that they have so few products tested is that they receive very little requests for that data.

Quote:
As per our conversation Roxul has done very little testing to airflow resistivity, however, we have tested 5 products in 2008. Below are the results. All samples were 3” thick.

All units are in mks rayls/m

TopRock DD: 12.7 x 10^4
AFB: 6.7 x 10^4
CavityRock MD: 6.4 x 10^4
FabRock LT: 4.1 x 10^4
RockBoard 40: 5.2 x 10^4
Yes, the Rockboard 40 is 4 lb/ft³ (64 kg/m³) product. That is the nominal non-silicon wool density material that we take as being equivalent to OC 703. So much for across the baord generalizations. It should be noted that in the same manner, Ultratouch insulation (cotton*) appears to have significantly higher gas flow resistivity.

Andre

*I originally wrote sheep's wool. DanDan's following post is correct in what he wrote about sheep's wool.

Last edited by avare; 3rd August 2011 at 10:34 PM.. Reason: sheep's wool is not cotton
Old 3rd August 2011
  #23
Gear Guru
Compilation

Sometime I hope to compile a table of various products/density/gfr.
Andre, I think Ultratouch is cotton, and quite an underachiever at LF as you have previously shown us. I would love to know it's gfr, if it isn't posted here already. Conversely I have hopes for Sheepswool, which 'appears' to have low gfr. Anyone who has tried to blow through a sheep would know that.....heh
I would love to know the gfr of Sheepswool, even if it is vague.

DD

Last edited by DanDan; 3rd August 2011 at 10:23 PM.. Reason: Baad
Old 3rd August 2011
  #24
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avare's Avatar
 

Quote:
Originally Posted by DanDan View Post
Sometime I hope to compile a table of various products/density/gfr.
I get the feeling that that would be like herding cats. At least trying to make sense of the data trends. Perhaps adding fibre length and diameter, binder quantity and volume, and dynamic stiffness would help decipher patterns. With these pices of information, the need to know the tortuousity should be nimimal. The manufacturers should have this data...

Quote:
Andre, I think Ultratouch is cotton, and quite an underachiever at LF as you have previously shown us.
Thank you for the correction. I have edited the origonal post to include the correct information.

It is not so much an underacheiver, but that available test data indicates different properties. The data implies significantly greater gas flow resistance than we would have guessed from the material's density.

Quote:
I would love to know it's gfr, if it isn't posted here already. Conversely I have hopes for Sheepswool, which 'appears' to have low gfr. Anyone who has tried to blow through a sheep would know that.....heh

I would love to know the gfr of Sheepswool, even if it is vague.
Excellent point!

Dreaming,
Andre
Old 3rd August 2011
  #25
Gear Maniac
 
aackthpt's Avatar
 

DD, the following just says 'wool', doesn't say any specific type. I can only assume it means sheep's wool.
ScienceDirect - Applied Acoustics : Acoustical properties of wool
So possibly a trip to an engineering library might answer your question? Or 40 USD of course.
Old 4th August 2011
  #26
Gear Guru
Range

Quote:
10 and 100 kg/m3 with flow resistivities from 500 to 15 000 MKS Rayls/m.
Seems like a very broad range of density for wool. I have seen wool carpet underlay but 100KG?
The corresponding GFRs are interesting though.
DD
Old 6th August 2011
  #27
Gear Addict
 

There is so called industrial wool, compressed to sheets. These may even be hard to bend. I´ve got one as a mousemat.
Old 6th August 2011
  #28
Gear Guru
Natural

Sheeps wool as a Mouse Mat.......heh

DD
Old 23rd January 2012
  #29
Gear Guru
Physicist needed!

Courtesy of G.E. I took an interest in Caruso Iso Bond some time ago.
It seems to be a very interesting material. Rigid light and a good performer.
No scratchy or other nasty or toxic aspects.
Caruso sent me quite a bit of data, in German, but good absorption figures and so on.
So, to topic here. In English they state :-

Flow Resistance per unit length >5kNs/m^4

Could someone translate into the form used in the calculators for me/us please?

DD
Old 23rd January 2012
  #30
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avare's Avatar
 

Quote:
Originally Posted by DanDan View Post
Flow Resistance per unit length >5kNs/m^4
I may be wrong, but with rayls being pascals.s/m² and a pascal being a force of one newton over a m², the equivalent is >5k rayls.

Someone, please, do a dimensional analysis.

The concern is of course what is meant by "greater than." Does it mean "near, but below" or "we know it will never be this low."

Andre
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