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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 for
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 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.