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GSBN: Digest for 12/31/04



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-> Re: GSBN:Question re R-values
     by stoneandstraw@...
-> RE: GSBN:Re: Question re R-values
     by stoneandstraw@...
-> Re:  RE: GSBN:Re: Question re R-values
     by Strawnet@...


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Date: 31 Dec 2004 00:20:38 -0600
From: stoneandstraw@...
Subject: Re: GSBN:Question re R-values

Bob was involved in the research that led to the Energy Commission report,
as were Greg and Turko (those Straw Dawgs), David Eisenberg, and myself.
The numbers were all over the place.  However, the best test gave a value
that equates to about R-1.5/inch.  for the 'standard' bales in central
California (~22.5" wide), that results in an R-33.  The Energy Commission
took the conservative approach of assigning straw bales walls an R-30,
until someone comes along who has the time and energy to devote to more
testing.
I generally tell people who ask that the tested value is around R-30, but
that in California, the walls perform more like R-45 due to the thermal
lag.  I put the "California" qualifier in there because in a location where
the temperature drops below freezing and stays there for a couple weeks,
the tested value is likely to be the more accurate one.  The thermal lag
only comes into play where the day time temperatures are significantly
higher than the night time temps.

Nehemiah Stone


> [Original Message]
> From: Bob Bolles Bob@...
> To: GSBN GSBN@...
> Date: 12/29/2004 10:37:13 AM
> Subject: Re: GSBN:Question re R-values
>
> California Energy Commission has set Straw Bales at R-30, and that is the
> value we use.
> bb
>
> Bob Bolles
> Sustainable Building Systems
> San Diego, CA - USA
> Bob@...
> www.StrawBaleHouse.com
>
> ----- Original Message -----
> From: "Joyce Coppinger" jc10508@...
> To: "GSBN" GSBN@...
> Sent: Wednesday, December 29, 2004 10:04 AM
> Subject: GSBN:Question re R-values
>
>
> > When answering the question about R-values of bale walls and buildings,
I
> > usually use a range rather than a specific number. A request has come in
> > asking for a specific R-value to satisfy the building codes officials
who
> > are reviewing a project in the Northwest USA.
> >
> > I'm wondering what answer you would give to this question?
> >
> > Joyce
> >
> >
> >
> >
> > --
> > Joyce Coppinger
> > Managing Editor/The Last Straw, the international quarterly journal of
> > strawbale and natural building
> > The Green Prairie Foundation for Sustainability/GPFS (publisher)
> > PO Box 22706, Lincoln NE 68542-2706 USA
> > 402.483.5135, fax 402.483.5161
> > thelaststraw@...
> > www.thelaststraw.org
> >
> > Check the Calendar on the TLS web site at www.thelaststraw.org for a
list
> > of
> > straw-bale and natural building workshops, training opportunities,
events
> > and conferences.
> >
> > The First Ten Years of The Last Straw Journal on CD-Rom (Issues 1-40
fully
> > indexed and searchable) will be available soon. $35 plus shipping and
> > handling ($5.00 if mailed within the US and Canada; please contact TLS
for
> > s/h for other countries). To order, call 402.483.5135, fax 402.483.5161,
> > or
> > send email to thelaststraw@.... An order form is
available
> > on
> > the web site.
> >
> > ----
> > GSBN is an invitation-only forum of key individuals and representatives
of
> > regional straw construction organizations. The costs of operating this
> > list are underwritten by The Last Straw Journal in exchange for use of
the
> > GSBN as an advisory board and technical editing arm.
> >
> > For instructions on joining, leaving, or otherwise using the GSBN list,
> > send email to GSBN@...HELP in the SUBJECT line.
> > ----
> >
> >
>
>
> ----
> GSBN is an invitation-only forum of key individuals and representatives
of regional straw construction organizations. The costs of operating this
list are underwritten by The Last Straw Journal in exchange for use of the
GSBN as an advisory board and technical editing arm.
>
> For instructions on joining, leaving, or otherwise using the GSBN list,
send email to GSBN@...HELP in the SUBJECT line.
> ----




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

Date: 31 Dec 2004 00:33:07 -0600
From: stoneandstraw@...
Subject: RE: GSBN:Re: Question re R-values

Derek,

I would be careful about quoting the Sandia Labs' report.  It had some
serious limitations.  Also, be careful with interpretations of ORNL's
tests.  ORNL has develoed a term they call "effective R-value."  While it
does do a better job of accounting for extra lumber in the wall and the
lost insulation value of spaces left unisulated, it unfortunately also
mixes infiltration with thermal conductance - what the R-value is supposed
to measure.

However, you are right that a simple comparison of fiberglass' R-19 to
straw bales' R-30 (or R-33) is not appropriate either.  Recent research
sponsored by the Energy Commission indicated that an "R-19 wall" as it is
generally constructed, only gives about R-12.  If extra care is taken to
make sure that insulation surfaces are flush to siding and sheetrock
surfaces, that insulation surrounds all wiring, that it fits tight around
switch and outlet boxes, and that it completely fills all bays, then the
"R-19" insulation will give you about R-14.  Whoopee!

On the whole, I agree with your approach of avoiding the simplistic answer.
However, I have also found that some people are more than a little turned
off by a technical answer to what they thought was a simple question.

Nehemiah

> [Original Message]
> From: Derek Roff derek@...
> To: GSBN GSBN@...
> Date: 12/29/2004 12:27:06 PM
> Subject: GSBN:Re: Question re R-values
>
> I think it is risky to pretend that a complex issue is simple, to satisfy
a
> momentary need.  In talking with clients, enthusiasts, code officials and
> the curious, I am constantly bemused by the mis-application of
information,
> and the incorrect analysis and extension of data.  At a minimum, I feel it
> is essential to quote a source for any simplification, as Bob did below.
>
> Most people that I talk to are mentally comparing strawbale to the myths
of
> the US insulation grail, R-19 fiberglass batts.  If I say that strawbale
> has an R-value of thirty, many people conclude that it is just a little
> better than fiberglass.  I prefer to say that strawbale as a building
> component has an R-value of 50, according to tests at Sandia National
> Laboratories tests.  I compare this to the R-19 fiberglass that they are
> familiar with.  Next I say that a well-built SB wall will have an R-value
> of around 30, according to Oak Ridge National Laboratory (ORNL) tests.  I
> compare this with the ORNL ratings of R-7 to R-11 for a wall insulated
with
> nominal R-19 fiberglass.
>
> I find that most people have never considered the possibility that R-19
> fiberglass doesn't guarantee an R-19 wall.  However, they can understand
> and accept the concept that a whole wall will have a lower average
> insulation value than its most insulating component.  I also mention that
a
> poorly built wall, whether insulated with SB, fiberglass, or anything
else,
> can have a much lower insulation value.
>
> This is the simplest way to answer the R-value question that I have found,
> while still being effective in conveying some of the essential
information,
> and providing a fairly accurate basis for comparison.
>
> Derek
>
> Derek Roff
> Language Learning Center
> Ortega Hall 129, MSC03-2100
> University of New Mexico
> Albuquerque, NM 87131-0001
> 505/277-7368, fax 505/277-3885
> Internet: derek@...
>
> --On Wednesday, December 29, 2004 10:10 AM -0800 Bob Bolles
> Bob@... wrote:
>
> > California Energy Commission has set Straw Bales at R-30, and that is
the
> > value we use.
> > bb
> >
> > Bob Bolles
> > Sustainable Building Systems
> > San Diego, CA - USA
> > Bob@...
> > www.StrawBaleHouse.com
> >
> > ----- Original Message -----
> > From: "Joyce Coppinger" jc10508@...
> > To: "GSBN" GSBN@...
> > Sent: Wednesday, December 29, 2004 10:04 AM
> > Subject: GSBN:Question re R-values
> >
> >
> >> When answering the question about R-values of bale walls and
buildings, I
> >> usually use a range rather than a specific number. A request has come
in
> >> asking for a specific R-value to satisfy the building codes officials
who
> >> are reviewing a project in the Northwest USA.
> >>
> >> I'm wondering what answer you would give to this question?
> >>
> >> Joyce
> >>
> >> Joyce Coppinger
> >> Managing Editor/The Last Straw, the international quarterly journal of
> >> strawbale and natural building
>
>
> ----
> GSBN is an invitation-only forum of key individuals and representatives
of regional straw construction organizations. The costs of operating this
list are underwritten by The Last Straw Journal in exchange for use of the
GSBN as an advisory board and technical editing arm.
>
> For instructions on joining, leaving, or otherwise using the GSBN list,
send email to GSBN@...HELP in the SUBJECT line.
> ----




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

Date: 31 Dec 2004 02:07:51 -0600
From: Strawnet@...
Subject: Re:  RE: GSBN:Re: Question re R-values

Joyce, et al...

I think the discussion is getting down to what is most useful. When I
talk about the ORNL testing, I usually say that the bale wall we tested
in that lab had an R-value roughly double that of the 2x6 stud wall with
perfectly installed R-19 fiberglass batt insulation (+/- R-30 for the
bale wall to +/- R-14 for the fiberglass insulated wall. That's excellent
insulation.

But I typically also talk about the thermal performance of wall
assemblies versus the R-value, because R-value alone is only part of the
story. Thermal mass and its location and relationship to the insulation
has a lot to do with the overall performance of an assembly. Different
assemblies with exactly the same R-values can perform quite differently
depending on the configuration of the wall.

My typical example is a concrete block wall furred out on the inside and
insulated with fiberglass batts and drywall, versus the same concrete
block wall with an equivalent amount of insulation on the exterior. Same
R-value but one has mass interior to the insulation and the other leaves
the mass out in the weather. The performance is much better with the
externally insulated mass.

Taking that a step further and including radiant comfort - your body's
sensitivity to radiant heat, bale walls' performance is actually
significantly better than the R-value alone would indicate because the
interior plaster represents a lot of thermal mass pretty well isolated
from exterior temperature changes - so the plaster tends to stay at
ambient air temperature in the room. Thus your body is not trying to heat
a cold wall or be heated by a hot wall and so the you can be comfortable
with cooler air temps in the winter and warmer interior air in the
summer. This can make a big difference in heating and cooling loads and
bills.

David Eisenberg

>Derek,
>
>I would be careful about quoting the Sandia Labs' report.  It had some
>serious limitations.  Also, be careful with interpretations of ORNL's
>tests.  ORNL has develoed a term they call "effective R-value."  While it
>does do a better job of accounting for extra lumber in the wall and the
>lost insulation value of spaces left unisulated, it unfortunately also
>mixes infiltration with thermal conductance - what the R-value is supposed
>to measure.
>
>However, you are right that a simple comparison of fiberglass' R-19 to
>straw bales' R-30 (or R-33) is not appropriate either.  Recent research
>sponsored by the Energy Commission indicated that an "R-19 wall" as it is
>generally constructed, only gives about R-12.  If extra care is taken to
>make sure that insulation surfaces are flush to siding and sheetrock
>surfaces, that insulation surrounds all wiring, that it fits tight around
>switch and outlet boxes, and that it completely fills all bays, then the
>"R-19" insulation will give you about R-14.  Whoopee!
>
>On the whole, I agree with your approach of avoiding the simplistic answer.
>However, I have also found that some people are more than a little turned
>off by a technical answer to what they thought was a simple question.
>
>Nehemiah


"Not everything that counts can be counted,
and not everything that can be counted counts."
- - sign over Albert Einstein's desk at Princeton



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