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Re: GSBN:Re Thermal Properties of Straw Bale Walls



The test we did in California had one wall laid flat and one on edge.  And
yes, we got the same total value for the wall both orientations, meaning
that the R/inch for bales on edge is higher than for bales laid flat.
However, we only got about R-0.9/inch both ways due to serious issues with
the top few inches of the walls, inadequate drying (curing) time, and other
anomalies.  The ORNL test was only with bales laid flat.  I don't suggest
putting too much stock in the on-edge/laid-flat difference we "found" in
CA.  ...at least not until someone repeats the experiment with better QC.
BTW, the R/inch for the on-edge bale wall in CA was about R-1.3/inch.
Since no such test was done at ORNL, THAT is the value that someone should
use if they feel a need to have a separate one for "cross orientation."

Nehemiah Stone
stoneandstraw@...



> [Original Message]
> From: Martin Hammer mfhammer@...
> To: GSBN GSBN@...
> Date: 5/17/2007 4:40:23 PM
> Subject: Re: GSBN:Re Thermal Properties of Straw Bale Walls
>
> Hello Nehemiah,
>
> Is there not a different R-value per inch for bales on-edge and laid-flat?
> My understanding is that the Oak Ridge National Lab test showed this.  The
> result, in California, being that walls with 3-string bales on-edge (15"
> thick) and laid-flat (23" thick) are considered by the California Energy
> Commission to have the same R-value of R-30.  If I am correct that would
> yield an R-value per inch as follows:
>
> On-edge:  R-2 per inch
> Laid-flat:  R-1.3 per inch
>
> I know there has been discussion about straw orientation, which in theory
> explains the higher unit R-value for a bale on-edge, and how not all
baling
> machines bale straw with a clear orientation.  (I can tell you that the
> straw orientation of the bales we're making manually in Pakistan have no
> orientation.  We just grab big balls of straw and stuff them into the
> compression mold!)
>
> I also wonder if there is any appreciable difference from one grain to
> another.
>
> Any sage thoughts?
>
> Martin Hammer
>
>
>
> > John,
> >
> > For all intents and purposes, the value per inch is constant once you
get
> > to the size of a bale.  It might not be if you were dramatically
> > down-sizing from the test specimens, but going larger, relative
uniformity
> > is a safe assumption.  What we found in the ORNL test was about 1.47 per
> > inch (3.82/m Aussie).  Since the render adds mass w/o any significant
> > insulation, the 36" bale wall you are considering should be about R-53
> > (~R-9.4 Aussie).
> > Hope this helps.
> >
> > Nehemiah Stone
> > stoneandstraw@...
> >
> >
> >
> >> [Original Message]
> >> From: John Glassford jacksflat@...
> >> To: GSBN GSBN@...
> >> Date: 5/17/2007 1:40:33 PM
> >> Subject: GSBN:Re Thermal Properties of Straw Bale Walls
> >>
> >> G ' day Balers
> >>
> >> Can any of you help with thermal properties of jumbo bales?
> >>
> >> I have Nehmiah Stone's work and was wondering if I can extrapulate
> >> from them inch by inch?
> >>
> >> If so what value would you give a 900mm or 36" straw bale wall plus
> >> 100mm or 4" of render?
> >>
> >> We are about to build a community centre in Sydney for the Fairfield
> >> City Council from jumbo balaes 2.4m x 900mm x 600mm.   Bales 6 high or
> >> a wall of 3.8 m finished including top and bottom plates.  The
> >> building will be used for community events in the heart of Sydney or
> >> it's geographical centre.  Will be good for straw bale. Bales on the
> >> flat i.e. 900mm.
> >>
> >> Any help will be appreciated thanks.
> >>
> >> Aussie R values are around R7-9 for straw bales so multiply by 5.6 for
> >> USA R values, I think.
> >>
> >> Kind regards
> >> John Glassford
> >> Huff 'n' Puff Constructions
> >> <a  target="_blank" href="http://www.glassford.com.au/";>http://www.glassford.com.au/</a>
> >> Mount Kilimanjaro Climb 28/8/07
> >> <a  target="_blank" href="http://www.coolamonrotary.com/kili/";>http://www.coolamonrotary.com/kili/</a>
> >> 61 2 6927 6027
> >>
> >> Yours in Rotary
> >> John Glassford
> >> International Services Director
> >> Rotary Club of Coolamon District 9700
> >> New South Wales, Australia
> >> Mount Kilimanjaro Climb 28/8/07
> >> <a  target="_blank" href="http://www.coolamonrotary.com/kili/";>http://www.coolamonrotary.com/kili/</a>
> >> Road MAPS to Africa Web Site:
> >> <a  target="_blank" href="http://www.coolamonrotary.com/maps/";>http://www.coolamonrotary.com/maps/</a>
> >> Chair RFFA (Australia): Rotarians Action Group Fighting AIDS.
> >> <a  target="_blank" href="http://rffa.org/";>http://rffa.org/</a>
> >> 61 2 6927 6027
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