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Re: GSBN:Tech points re: tests



Chris,

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 for 23 Celsius and 50% rel humidity

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

 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 webpage)

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



Rene Dalmeijer