[GSBN] Fwd: [nbne] R-value of compressed straw panels

[asbn]

Dear Tristan et al

When we use strawboards in Europe (as separation walls), we mainly use  
Ecopanely from Czech Republic.
This product is CE certified (European Technical Approval).
The website is in english, too: http://www.ekopanely.cz/en/

Values of heat insulation magnitude
heat transfer coefficient:
λ = 0,099 Wm-1 K-1, R = 0,5858 m2 KW-1
diffusion resistance: RD = 4,6 * 109 ms-1
diffusion resistance coefficient: μ = 9,7
heat penetration coefficient:
U = 1,04 – 1,39 W/m2 * K
according to the construction layout,
season, and heat flux

There is another board called iStraw with the same values:
http://www.istraw.de/ site only in german

all the best
Herbert
-----------------
asbn - austrian strawbale network
3720 Ravelsbach, Baierdorf 6
Tel. 02958-83640
asbn at baubiologie.at
www.baubiologie.at



Am 22.04.2013 um 04:12 schrieb ejgeorge at riseup.net:

> Hey again all. This question came up on the NBNE list from Tristan  
> Roberts of BuildingGreen. Robert Riversong's response is included  
> below Tristan's post, but I thought someone over here might also  
> have more information on the purported Stramit lab test.
>
> ----- Forwarded message from tristan at buildinggreen.com -----
>
>
> Hi,
>
> Does anyone have insight into the R-value of compressed straw panels  
> such as Stramit (currently produced in Texas) or Agriboard (no  
> longer being produced)?
>
> Stramit USA claims R-3.03/inch, and I have even seen press releases  
> claiming R-3.35. However, the company can't produce a lab test to  
> prove this to me, and there is history of R-value inflation in  
> compressed straw, as this old EBN article talks about:
>
> http://www.buildinggreen.com/auth/article.cfm/1998/1/1/Agriboard-s-Inflated-R-value-Claims/
>
> I supposed there might be less convective loops in a compressed  
> straw panel compared with a bale, but intuitively it's hard for me  
> to picture how compressed straw has higher R-value.
>
> It's probably a longshot, but I wondered if anyone has any insight  
> (or maybe you know someone who might). Also, if you have any recent  
> experience with Stramit, I'd like to talk with you.
>
> thanks!
>
> Tristan
>
>
> ____________
> Tristan Roberts
> Editorial Director
> BuildingGreen, Inc.
> http://www.BuildingGreen.com
> http://www.LEEDuser.com
>
> (802) 257-7300 x121
> tristan at buildinggreen.com
>
> -----------end forwarded message -----------
>
> Robert's reply:
>
> Loose fibrous materials often increase in R-value per inch with  
> increased density - up to a point of diminishing returns - and I  
> have no reason to doubt that compressed straw would be more  
> insulative than straw bales.
>
> Loose-fill fiberglass, for instance, is about R-2.5/inch, while  
> fiberglass batts, which used to be about R-3.14/inch for standard  
> R-11 batts, were increased to R-13 (3.7/inch) in "high-density  
> batts", and semi-rigid fiberglass board as well as dense-pack Spider  
> is about R-4/inch.
>
> Similarly, loose fill cellulose is about R-3.4/inch at 1.4 pcf  
> density, while dense-pack cellulose at 3+ pcf can be as much as  
> R-3.8/inch.
>
> But the density range that Stramit specs of 15.6-40.5 pcf puts it at  
> about the same density range as solid wood, which is about R-1.25/ 
> inch. So I also question their claim of R-3.35/inch.
>
>
>
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