Virgin farmed wool... good for acoustics? They say its better than everything else...

[Big_Bang]

Thanks to Paul P's link on another thread I opened, compairing and debating health issues with rockwool, the last poster suggested to take a look at these guys...

Black Mountain Insulation

They praise alot, like

" we aim to be the most competitively priced in the whole of Europe "

" No protective clothing or breathing masks are required "

" Natural sheep's wool offers improved thermal and acoustic ratings over most man-made materials "


I´d like to contact these folk as all this is very promissing, but I´d like to ask your help on the type of information to ask. I dont like sending 15 emails a week with new queries, so what sort of info in one "package" should I request, so as to compare with your usual materials, regarding price and acoustics?

- density ?
- price per... m2, m3 ?

quite frankly, can't think up anything else as this is the first time I'm getting into building traps.

Thank you!!

[Big_Bang]

Well, by visiting the website it is clear they are totally oriented towards the insulation market, they have a coupe of pdf's containing all sorts of thermal specs.

What you are suggesting is absolutely valid, but in real life who would finance up such endeavour for an inquiring customer who will buy peanuts of their production?

Now... if I make relevant questions, they might have, or measure.

I believe people are innocent until proven guilty... I have no reason to doubt them. Look at the pdf's

[avare]

Originally Posted by Big_Bang

- density ?
- price per... m2, m3 ?

Density is meaningless. Wool has has a much lower density than minerals, which includes, silicon aka fiberglass and Rockwool type materials. What is usefull is the actual sound absorption data and gas flow resistance.

Andre

[PaulP]

Originally Posted by Big_Bang

Damn, I am starting to regret ever opening this thread.

Don't worry about it. Not everyone here knows what courtesy is.

For the wool, I'd call up the company. Who knows, they may have data
available and be willling to help you out.

Paul P

[DanDan]

BB your are welcome here. I would like to know how those Farmers prove they are Virgins

As Andre said, density is not absorption. There are visible parallels between them though.
In general Sheeps wool and Hemp tend to be of quite low density. I would venture 20 KG/metre cubed.
(Hey could someone please tell me how to do that superscript squared or cubed thing)
If you wish to trust the density comparison, this suggests that it would work fine in thick traps. Personally I wouldn't doubt that.

Andre, many of these materials will never get tested acoustically. The thermal market is so much bigger than our little world. Is there any relationship between the thermal specs and Gas Flow Resistivity, and absorption? i.e. Can we translate or even extrapolate with a reasonable chance of success?

DD

[SAC]

I think Andre will concur (please advise if you know of a way!), there is no necessary direct relationship between density and porosity between mixed materials.

Larger filaments, or even ''sheets' of lower density versus small filaments of higher density, further modified by material fabrication variation (inclusions of air or other filler or inert materials) may all factor into materials having equal mass per unit volume, but radically difference porosity and gas flow characteristics.

The world would be much simple (and much less interesting!) if there were, but the mass distribution of materials and their variations in size simply make this relationship extremely non-linear.

[avare]

Originally Posted by DanDan

As Andre said, density is not absorption. There are visible parallels between them though.
In general Sheeps wool and Hemp tend to be of quite low density. I would venture 20 KG/metre cubed.
(Hey could someone please tell me how to do that superscript squared or cubed thing)
Andre, many of these materials will never get tested acoustically. The thermal market is so much bigger than our little world. Is there any relationship between the thermal specs and Gas Flow Resistivity, and absorption? i.e. Can we translate or even extrapolate with a reasonable chance of success?

Wow, you have an acousitc mouthfull there.

Easy things first, m^3 is using the symbol on the number 6 key. Doing m³ is done by going into the character map usually hidden on the menu>accessories menu and then going through the characters for the Superscript Three. Okay, the easy one is done...

Thermal Specs and Gas Flow Resistivity, and Absorption Relationships.

The short answer is no.

The long answer is no.

Thermal specs are the result of many factors, NOT NECESSARILY INCLUDING gas flow resistance. While low gas flow resistance is good for insulation where convection can occurr, it is not significant for in partition insulation in general terms. For sound absorption, the appropriate flow resistance is mandatory. This is why most expanding foams that are good for thermal insulation have no desirable sound absorption. The closed cells of the foam prevents the absorption of sound.

Gas flow resistivity and absorption do have a relationship, together with the thickness of the material.

Density in and of itself it meaningless. Density of the materail is dependent, amongst other things, on the physical density of the material used. Glass insulation is mostly the mineral silicon. What we call mineral wool is mostly variations on volcanic rock and slag form steel mills. The silicon is lighter than the generic minerals used in mineral wool. An equivalent size fiber in glass is lighter than in the mineral wool. We see this in our generic response of "use 3lb/ft3 fiberglass or 4lb/ft3 rockwool. Helping keep things confusing, notice I used trade names in the last sentence. Beyond the density of the main material difference, the trend of the insulation density and gas flow resistance is also different. Teryy Montlick published a graph on Studiotips in this thread.

Going to the OP's material question. There is a similar product in North America called Ultratouch. From examining its absorption test data, the performace is similar to our 703 (notice how I keep using tradenames to confuse things?) at 4" thick. At 6" deep there appears to be low frequency reflection occurring in the material. Putting these two points together, it is reasonable to assume that the gas flow resistivity is in the same general (for acoustic) but definitely higher range than 703. Ultratouch has a density of 1.6 lb/ft3. Your 20 kg/m^3 is just about spot on! With marketing pressures to simplify data, I would not be surprised if it actually is 20 kg/m^ that endured a marketing conversion to imperial.

Above there are three materials with over a 2.5:1 ratio in density. The high being 4 lb/ft3 mineral wool and the low being 1.6 lb/ft3 cotton insulation. All three show similar absorption characteristics at 4" thickness. The pattern of resistance versus density is marketedly different for two of the materials. We (or at least I)do not have any data on the gas flow/density relationship for cotton wool.

I hope this honest answer helped people.

Ps. yes Dan, part of my gas flow resistnce/gapping article will include these factors.

Completely,
Andre

[DanDan]

That is one fabulous answer, certainly helpful. Thank you Andre.
It gives rise to the possibility or maybe hope, that the lighter 'green' materials that many find so attracitve, may perform very well.
Let's hope someone does a test soon.
Now that I think of it, Glenn, aren't we supposed to meet in Chicago for Tests and Drinks? :-)
DD

[Big_Bang]

Indeed a GREAT informative answer!

Thank you!

[avare]

Originally Posted by DanDan

That is one fabulous answer, certainly helpful. Thank you Andre.
It gives rise to the possibility or maybe hope, that the lighter 'green' materials that many find so attracitve, may perform very well.
Let's hope someone does a test soon.

You are welcome. +1 on testing data. From what we have seen, green materials seem suitable, but actual performance (test) data is required to know for certain.

On a slight tangent, I emailed the company asking for more information about Ultratouch and received no response. It is particularly irksome because while we do not discuss gas flow resisitivity much, it is a basic material property that should be known from heat insulation testing.

Andre

[DanDan]

I reckon Bob is listening all the time, and adding in the products we speak of..... (or probably similar products)
From the great www.bobgolds.com

Ultratouch
R-13 3.5" 0.95 1.30 1.19 1.08 1.02 1.00 1.15
R-19 5.5" 0.97 1.37 1.23 1.05 1.00 1.01 1.15

Thermafleece 100mm
0.34 0.44 0.63 0.76 0.87 0.95 0.99 1.00 1.01 0.95 0.93 0.94 0.94 0.95 0.98 1.01 1.01 1.04

The sheep aren't lookin so good today, maybe later after a few tinnies....

DD

[avare]

Originally Posted by DanDan

Thermafleece 100mm
0.34 0.44 0.63 0.76 0.87 0.95 0.99 1.00 1.01 0.95 0.93 0.94 0.94 0.95 0.98 1.01 1.01 1.04

The sheep aren't lookin so good today, maybe later after a few tinnies....

Thanks Dan. I had not seen the Thermafleece on Bob's excellent website. Another hole in acoustic data filled. Looking at the data, I suspect that the Thermafleece is very low density. Do sheep come in different weights?

Baadly,
Andre

[DanDan]

mind racing with all sorts of dodgy replies, better not...
just remove the 'in different weights' from the last post

Sorry sorry sorry....DD

[johndykstra]

Andre,

...that's priceless.