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GSBN: Digest for 4/21/04



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-> Tech points re: tests
     by tlseditor@...
-> Re: GSBN:Tech points re: tests
     by billc_lists@...
-> Re: GSBN:Tech points re: tests
     by "rene.dalmeijer" rene.dalmeijer@...
-> RE: GSBN:Tech points re: tests
     by jfstraube@...


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Date: 21 Apr 2004 14:00:43 -0600
From: tlseditor@...
Subject: Tech points re: tests



Hello All,

I'm working with Erwin Schwarzmuller in Austria on a TLS article
about the series of tests that have recently been performed on bale
walls in Austria. It is an excellent article, especially considering
the language barrier we're working with.

There are a couple of technical points that I don't understand, and
it's difficult for Erwin to translate this technical stuff for me.
I'm wondering if any of you tech-types out there could help me figure
my way through one particularly tricky section, so I can put it in
language that most TLS readers (and myself!) can understand.

The following is the tricky section:

"Thermal conductivity was measured between Lambda (I havenot found
the greek symbol in the mail editor) 0,0395- 0,041W/mK and from that
resulted a Lambda D (23/50) = 0,046 W/mK (building practical
calculation value for 23#161#C and 50% constant air humidity). "

I am hoping that somebody can translate this one for me, perhaps into
values that will be comparable to other tests.

Thanks!

Chris
- -- 


***************************

Chris Magwood / Camel's Back Straw Bale Construction
http://www.strawhomes.ca

Interested in bale building? Have you subscribed to
The Last Straw Journal?
You should!
  http://www.thelaststraw.org



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Date: 21 Apr 2004 16:13:46 -0600
From: billc_lists@...
Subject: Re: GSBN:Tech points re: tests

For those who saw this line

>calculation value for 23#161#C and 50% constant air humidity). "


as containing "for 23#161#C and ...", I believe that the degree 
symbol didn't translate correctly and it should read

23 degrees C




- -- 
Bill Christensen
http://sustainablesources.com/contact/

Green Building Professionals Directory: http://directory.sustainablesources.com
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Books/videos/software: http://bookstore.sustainablesources.com/


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Date: 21 Apr 2004 16:15:48 -0600
From: "rene.dalmeijer" rene.dalmeijer@...
Subject: 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



----------------------------------------------------------------------

Date: 21 Apr 2004 16:57:26 -0600
From: jfstraube@...
Subject: 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
insulations.
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
http://www.civil.uwaterloo.ca/beg


- -----Original Message-----
From: GSBN [mailto:GSBN@...] On Behalf Of
rene.dalmeijer
Sent: April 21, 2004 17:58
To: GSBN
Subject: 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

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