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GSBN: Digest for 5/8/03

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-> CalifoRnian values (was re: from the Crest list)
     by "Rob Tom" rw_tom@...
-> Yahoo! Auto Response
     by mbenn1035@...


Date: 8 May 2003 12:09:29 -0500
From: "Rob Tom" rw_tom@...
Subject: CalifoRnian values (was re: from the Crest list)

Rocky et al;

I don't recall the specifics of the CEC tests at the ATI labs but I do 
recall that at the time,  I was shaking my head at the manner in which the 
test panels were prepared before being presented to the ATI people for 

I have vague memories of things like foam insulation board being jammed into 
cracks at the perimeter by the ATI people *during* the tests, presumably to 
reduce the haemorrhaging so that their results wouldn't make them look 
incompetent as a testing facility. (ie the GIGO syndrome)

I alos have vague memories of meaningless moisture content readings being 
taken (I think that it was of bales that weren't even inside of the test 
panel), while ignoring the  wet condition of the bales in the actual test 
panel which hadn't been allowed to dry out properly after stucco 

It was therefore no surprise that the CEC/ATI tests yielded disappointingly 
low R-values for straw but even more disappointing was the fact that the CEC 
chose to accept the test results as being representative of the insulating 
properties of straw bales.

There is no doubt in my mind as to the accuracy of the thermal resitivity 
values that JoE McCabe's testing provided, as they agree perfectly with the 
theoretical value that would be yielded by the equation used to estimate 
thermal conductivity (k) in the absence of data:

                     k = 0.281*Exp((0.0268*density)

(note that the above equation will yield a value that is dead-nuts in the 
middle of the two values that JoE provided in which he accounted for fibre 
orientation WRT heat flow... which also makes sense because the equation 
does not have a modifier for bale orientation)

The Sandia lab resistivity test results (although of bales of lower density 
than that used by JoE in his testing) would seem to further confirm that the 
CEC/ATI thermal resistance values are seriously flawed.

ie The ASHRAE values for the thermal resistivity of materials (presumably 
derived from testing of the materials under lab conditions) is regularly 
used to estimate the nominal thermal resistance of building assemblies for 
permit purposes etc. so why should there be a double standard for straw 
bales ?

Clearly, it was the process (ie of the  panel preparation, not of the ATI 
testing) which was flawed and it would seem to make sense that the tests 
should be re-done (making the necessary changes each time of course... they 
say that one of the signs of insanity is repeating the same actions over and 
over again expecting a different result each time) until the thermal 
resistance of the test walls approaches the values that are predicted by 
JoE's resistivity values.

Aside from the issue of respectability for strawbale housing (ie why would 
anyone go to the trouble of doing plastered SB walls to achieve a mere R-30 
when better than R-30 can be easily achieved in a thinner and 
readily-accepted-by-Conventionaldumb stick-framed wall ?), one would think 
that there would be more pragmatic consequences, such as in the reduction of 
the sizing of Code-required auxiliary heating (and cooling ?) systems, 
possibly even eliminating them in some instances, ultimately saving the 
homeowner's financial resources and perhaps more importantly, the planet's 

- --- * ---
Robert W. Tom
Kanata, Ontario, Canada

please visit:  http://www.theHungerSite.com daily

>Date: 6 May 2003 23:58:40 -0500
>From: stoneandstraw@...
>Subject: RE: From the Crest list
>In California, the accepted R-value (for compliance with the state building
>standards) is R-30.  That was based on a the results of a number of tests.
>One that I managed while at the California Energy Commission (CEC), two at
>Oak Ridge National Lab, the tests that Joe McCabe did, and testing that
>Sandia Labs did.  Every test had issues, and didn't all test the same 
>For example, McCabe and Sandia tested straw bales, while the other tests
>were of straw bale walls.

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Date: 8 May 2003 12:11:12 -0500
From: mbenn1035@...
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From: "Rob Tom" rw_tom@...
Subject: GSBN:CalifoRnian values (was re: from the Crest list)
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Rocky et al;

I don't recall the specifics of the CEC tests at the ATI labs but I do 
recall that at
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