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RE: GSBN:Tech points re: tests

I agree, not surprisingly, with Rene
The 0.04 value is too good to be true, and is equal to typical batt
On the other hand 0.1 is the value for good cedar -- I think SB are
better than solid cedar (18" of which gets you R25).
In general a value of maybe 0.06 to 0.08 (R32 to 42 for 18" bale)
depending on density would be reasonable for very well installed bales,
and 0.08 to .1 for some gaps and excessively fluffy bales.

John Straube
School of Architecture and Dept of Civil Engineering
University of Waterloo
Waterloo, Canada

-----Original Message-----
From: GSBN [mailto:GSBN@...] On Behalf Of
Sent: April 21, 2004 17:58
Subject: Re: GSBN:Tech points re: tests


At 09:59 PM 4/21/04, you wrote:
>"Thermal conductivity was measured between Lambda (I havenot found the 
>greek symbol in the mail editor)  and from that resulted a Lambda D 
>(23/50) =  (building practical calculation value for 23#161#C and 50% 
>constant air humidity). "

This is a no brainer.

The measured thermal conduction coefficient ranges between 0,0395- 
0,041W/mK resulting in a practical calculation value of 0,046 W/mK This
23 Celsius and 50% rel humidity

Lamda value conversion creates something quite awful unit wise if you go


  1 Btu.in/sq ft.hr.F= 0.144229 W/mK Therefore

0.046 W/mK = 0.319 Btu.in/sq ft.hr.F

ie this equates to a 2 string bale wall with stucco having an R Value

of 9.36 m^2K/W = 53.15 sq ft.hr.F/Btu (oops found a units mistake on my 

I regard this as a highly optimistic value and regard it with quite a
of hesitation for general use. My personal calculation value for Lambda
0.1 W/mK. What the presented value effectively means is that straw
almost on par with true insulation materials like rockwool which is
at around 0.035-0.040 depending on density and type.

Rene Dalmeijer