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Re: GSBN: re unplastered SBs and fire protection

Dear Alex,

No one has stated that if someone chooses to leave straw bale walls
un-plastered then they need to sprayed (dunked?) with fire retardant. Is
this because it is trivial/obvious or irrelevant/unproductive?

Borax is water soluble. Rain will wash it out of the straw, wood etc. if
it were exposed. Theirfore it can only be used inside (the house or the
wall/roof) or behind cladding.
I have experience with it. Cannot give you any recepy.

It is indeed very strange to test the seperate materials. Certainly if
only a handfull of the material was tested. I suggest you try to sent in
a whole bale and only have an indicated portion exposed to the fire
(indeed on the side without the strings).

a small comment on Nehemaih's comment on wires burning. This is only a
problem if the bales are not held in place by something else. What I
mean is that here in France it is very common to squish bales between 2
planks (thus making 'pillars'). These planks are generally 4*20 cm
(1.6*8 inch) or 5*15cm (2*6inch). Once a bale is in place one can cut
the strings without a problem (as I do for demonstration purposes during
my workshops).

As for Martins request:
I agree with what he suggests and always suggest people to plaster
behind cladding.
As for the looks (and sound) of unplastered bale walls... I feel they
are no match for an earth plastered SB wall. Now if you compare them
with cement plasterd walls... ;-)


lotan-build@...?crit :

The following ends with a comment about the ecohouse unplastered sb

This past summer we performed a full wall fire test at the Standards
Institute of Israel's testing facility.  No surprise to any of you: The
strawbale wall - 2 meters wide, 2.5 meters tall with 5 cm of earth plaster
(containing cut straw/chaff), interior (towards the fire) and exterior stood
the full 3 hours at over 1000 degrees centigrade.  The exterior temperature
of the wall did not increase at all.  At the completion of the test, the
authorities took samples of the plaster and the straw, 1 cm thick, to test
independently their flammability, drip and smoke indexes.  The plaster
performed perfectly and is now rated inflammable.  The straw of course burnt

The code states: all building materials that are thicker than 1.6 millimeter
must be tested independently, in addition to the full wall fire test, to
determine their flammability indexes.

So, in order to receive fire code approval, we need to send a straw sample
impregnated with a fire retardant in again for flammability testing.

1. I have seen "borax" mentioned often as an appropriate fire retardant and
termite protection measure.  For those of us without access to US
supermarkets - how do we make a boron based solution?  Have any Europeans
used this solution?
2. Are there other fire retardant solutions that we can make / purchase that
we can responsibly utilize, i.e. are not toxic or will in time be breathed
in by the building's occupants (like VOC's) that can be sprayed onto the
straw bale's exteriors before plastering (in order to work in accordance
with local standards)?

No one has stated that if someone chooses to leave straw bale walls
un-plastered then they need to sprayed (dunked?) with fire retardant. Is
this because it is trivial/obvious or irrelevant/unproductive?

In any case we need input on fire retardants to make fulfill the current
code stipulations.  In practice we realized that the real fire protection is
the earth plaster, integrally adhered immediately after wall construction.

Thanks - Alex

Alex Cicelsky
Education, Design and Construction
Center for Creative Ecology
Kibbutz Lotan
D.N. Eilot 88855 Israel
Tel: 054-979-9009
Fax: 08-635-6842
websites: www.kibbutzlotan.com

-----Original Message-----
From: Martin Hammer [<a  target="_blank" href="mailto:mfhammer@pacbell.net";>mailto:mfhammer@...]
Sent: Thursday, January 18, 2007 3:53 AM
Subject: Re: GSBN: re Ecohouse

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