Much of what we consider recent knowledge is really ancient. Possibly
you ran onto this paper from 1958, which is heavy on the chem side and
outside my forte, but starting at about page 23, it discusses both
minimums for borax (3 lbs per cubic foot) and boric acid. Since wood
runs about 40 pounds/cf then we're back to the neighborhood of that
7.5% number again. No surprises here. What was REAL intriguing was
Table 8, near the end of the paper, which compares glow of various
products and shows Ammonium Dihydrogen Phosphate as having the best of
both worlds, both good glow and flame retardant properties. This
chemical is also known as monoammonium phosphate or MAP. Funny thing,
it is the material used in many dry powder fire extinguishers. Go
figure. Also it is an agricultural fertilizer. I know many
fertilizers are destructive to cured concrete, but interestingly
enough, ammonium phosphate concretes are actually products your can
buy and are used in patching things like airfield runways because of
their fast cure and high compressive strengths. This product might be
worth looking into as a pc component. Anybody have any ?? Know where
to acquire?? I'm game to test.
http://ir.library.oregonstate.edu/dspace/bitstream/1957/2668/1/FPL_2136ocr.pdf
--- In papercreters@yahoogroups.com, "Neal Chabot" <sire@...> wrote:
>
> There seems to be a dearth of recent research on the boric
acid/borax combination. Perhaps I should not be so hasty in
criticizing the 1990 paper for keeping their solution hidden and not
citing previous research. This borate combination has been used in
homespun fire prevention for many years. For example there is the
following recipe:
> "Mix together nine ounces 20 Mule Team Borax and four ounces boric
acid in one gallon water."
>
> Boric acid is not very soluble in tap water (~6%). As very mildly
acidic it would only have a very small effect on the alkaline cement
reaction. Lack of solubility means that the water in a papercrete
mix would function primarily as a dispersal medium. Thus it is an
open question how much of the boric acid would be deposited on the
paper and how much would be drained away by the water.
>
> In contrast to boric acid, I am now very hopeful about the
possibilities of using borax in a PC mix. Here are some interesting
facts: Borax is a salt of boron and has been described as being, in
essence, half-neutralized boric acid. As opposed to the insolubility
of boric acid, borax is very soluble in water and forms an alkaline,
antiseptic solution that is used as a water softener, disinfectant,
detergent and welding flux. In solution (like your washing machine)
it is an alkaline buffer, which means it would help the cemeneous
reaction in a PC mix. It would also promote the solubility of
ingredients in PC.
>
> Borax's fire retardant properties may be due to the fact that when
it is heated above 62C borax puffs up to many times its original size
in a voluminous, spongy mass.
>
> Historical tidbits: many ancient people found valuable uses for
borax. The Egyptians used borax in mummification while the Romans used
it for glass making. Marco Polo's caravans transported it from Tibet
to Europe in the 13th century. Borax was a rare commodity until lake
bed deposits were found in California in the 1850s. The most famous
commercial borax mining operations were located in Death Valley in
California in the 1880s. Borax was recovered by dissolving "cotton
balls" made up of borate minerals in boiling water. As the solution
cooled the borax precipitated out. To get the borax to market was a
165 mile journey through the hot desert to the nearest railroad. Up to
ten tons of borax was carried on giant wagons that were pulled by
teams of 18 mules and 2 draft horses - the famous "20-mule teams."
These teams averaged two miles an hour; as a result the round trip
took 30 days to complete.
>
> Neal
>
>
>
> ----- Original Message -----
> From: Neal Chabot
> To: papercreters@yahoogroups.com
> Sent: Wednesday, August 01, 2007 12:20 PM
> Subject: Re: [papercreters] Re: PC fire resistance
>
>
>
> Duane,
>
> There article you reference is 17 years old and contains some
theories (like the char coating) that have been shown to be false
recently, at least in the 2004 paper that I used. The main problem
with the article is that it uses an unknown and unnamed commercial
boric acid/borax preparation. Since we don't know the name of this,
we don't know whether it is water based or how the two ingredients
were combined. Questionable research. It may be that as SG or
someone pointed out that mixing boric acid with borax with water may
not be a good way to combine these two ingredients, especially for the
necessary cement reaction in PC. It would be interesting to look at
the ingredients of currently available fire retardation products now.
>
> The paper does have a brief (and inadequate) description of the
fire tube test:
>
> In the fire tube test, the sample stick is inserted reside(sic) a
38 in.- (1-m-) long, 3-in.- (76-mm-) diameter galvanized iron tube. A
Bunson burner adjusted for a flame height of 11 in (280 mm)
> IS used to ignite the bottom end of the stick. Weight loss of the
stick is monitored Via a balance mechanism. The burner is removed
> after 4 rnin. The final percentage of weight loss is used as the
main criterion for comparison.
>
> Neal
>
>
> ----- Original Message -----
> From: mdumiller
> To: papercreters@yahoogroups.com
> Sent: Wednesday, August 01, 2007 8:38 AM
> Subject: [papercreters] Re: PC fire resistance
>
>
> I followed some advice in the article "The role of boron in
> flame-retardant treatments" which notes that :
>
> "Borax tends to reduce flame spread but can promote smoldering or
> glowing, On the other hand, boric acid suppresses smoldering but has
> little effect on flame spread. Therefore, these compounds are
normally
> used together."
>
> the other stat which I used was:
> "We estimated that loading levels of at least 7.5 percent add-on
level
> of borax-boric acid are needed for southern Pine to meet the
ASTM E 84
> class I requirement."
>
> The article I should have referenced was
>
http://www.fpl.fs.fed.us/documnts/pdf1990/levan90a.pdf
>
> I based my percentages on the weight of the fuel (the paper part) so
> my add-on was 8% of the paper weight. I used the 1:1:1 ratio of
> paper:portland:sand based on it being in the "middle" of a lot
of the
> recipes I saw, including at livinginpaper.com where they listed a
> 1 : 1.5 : 1 mix as a "starting point". I actually had some lime in
> the mix too, so my mineral portion was probably closer to 1 1/3
> mineral. One thing I did not do, and should have, was to
pre-dissolve
> the borax in hot water, this might have made a big difference. From
> my experience, Borax does not dissolve very well in cold water.
>
> SLURRYGUY thanks for your ongoing encouragement and advice !! I'll
> put more portland into the mix!!
>
> A point I had hoped to make is that, IMHO, if the mix is too
lean, and
> if proper fire-retardants are not added to the mix, the final
product
> is a death-trap if it's something you will live in. The recipes
being
> presented don't clearly indicate the critical issue here. There's a
> good reason that houses use non-combustible drywall over the
> combustible wood studs. If you intend to used PC for a house, you
> should pay particular attention to the mix to achieve a product that
> does not burn, or coat the surface with a plaster-type component to
> prevent surface combustion. In our excitement to further the use
of a
> green building material, it is easy to forget that the primary
> ingredient in these PC buildings is the same one we use to start a
> roaring camp fire.
>
> I'll try a similar test with more portland/mineral and pre-dissolved
> borax/boric acid as per the paper referenced above, and, if
anyone is
> interested am happy to share the results. I've noticed other PC
> websites are charging for their research, and sincerely
appreciate the
> open-source approach of this incredible forum. - Duane
>
> --- In papercreters@yahoogroups.com, "Neal Chabot" <sire@> wrote:
> >
> > Duane may be using the words boric acid and borax synonymously.
> The Forest Service research (2004 paper) that Duane implicitly
> references does not use borax in the tests for fire retardation. It
> uses boric acid in about a 3.5% concentration by weight. It also
> uses a chemical called guanylurea phosphate (GUP) by itself and in
> combination with boric acid. That combination (7.5% total weight)
> gave the best fire retardation properties, so it may be worth
> consideration for use in PC when maximum fire retardation is
important.
> >
> > Neal
> >
> > ----- Original Message -----
> > From: slurryguy
> > To: papercreters@yahoogroups.com
> > Sent: Tuesday, July 31, 2007 8:04 PM
> > Subject: [papercreters] Re: PC fire resistance
> >
> >
> > Hi Duane,
> >
> > Your results are close to inline with my experiments, but I don't
> > agree with your conclusions. Papercrete can be made such that it
> > will not continue to smolder. Please continue to experiment.
> >
> > I've conducted ALMOST the exact same test you conducted. I didn't
> > use any borax in a 1:1:1 paper, portland, sand test mix and
obtained
> > very similar results.
> >
> > 2-1 ratio of portand to paper seems to be very close to the point
> > where papercrete begins to become non smolder supporting.
> >
> > All papercrete will char on the surface when exposed to a
torch in
> > the manner you conducted your test. Higher mineral content mixes
> > will not continue to smolder. Also keep in mind that air
circulation
> > affects the test. If the small embers are fanned sufficiently
they
> > will tend to smolder hotter and longer.
> >
> > I'm curious about your logic about using a mixture of both
boric acid
> > and borax. One is acidic the other is alkaline. It seems they
would
> > chemically react and form a boric salt and a little (very little)
> > extra water. I don't know if boric salt has the same combustion
> > retarding properties as plain borax. I also don't know if
boric salt
> > will penetrate inside the paper fibers the same. 8% borates seems
> > very high and should have produced much better results than
observed
> > in your test. I'm wondering if the acid/alkaline reaction
might be
> > the reason. Just guessing.
> >
> > Keep in mind that portland is not the only material that can
raise
> > the mineral content to bring papercrete's fire resistance up to a
> > level that it will not continue to smolder. Clay works very well.
> >
> > 1:1:1:1 paper, portland, clay, sand with some plain borax will
fare
> > far far better. It might continue to smolder for a short time,
but
> > it will not consume the whole sample as you experienced.
> >
> > Alternatively 2:1:1 portland, paper, sand with plain borax
will also
> > fare well.
> >
> > 2:1:3:2 paper, portland, clay, sand with some plain borax will
also
> > fare well, but will take longer to dry.
> >
> > I encourage you to keep experimenting and reporting your results.
> > The experiment you conducted is not a failure. It's part of the
> > learning process.
> >
> > One more thought. When did you add your borates? My rule of thumb
> > is to add the borax to the paper as soon as possible during the
> > pulping process. This gives maximum opportunity for it to soak
into
> > the paper.
> >
> > (All ratios I listed are BY WEIGHT)
> >
> > Keep having fun. Keep sharing.
> >
> > --- In papercreters@yahoogroups.com, "mdumiller" <mdmiller1@>
> > wrote:
> > >
> > > I ran a fairly unscientific but interesting fire-resistance
test on
> > a
> > > PC sample I had made. From what I see, I'm not convinced
that PC
> > can
> > > be made totally fire resistant without a lot of additives
> > (increasing
> > > its cost to make). My mix included a borax/boric acid mix in a
> > > weight ratio equal to what the forest service recommends for
making
> > > wood more fire-resistant.
> > > What was interesting was that the material never at any time
as a
> > > fuel source produced an open flame, only smoldering. Another
fact
> > I
> > > found interesting was that the block continued to smolder for
> > twenty
> > > minutes after the propane torch was removed, looking like a
piece
> > of
> > > charcoal from the barbecue grill. I would imagine that doubling
> > the
> > > portland would slow the smoldering, but I had hoped the
borax/boric
> > > acid mix would extinguish the block once the torch was
removed--but
> > > no luck.
> > > Some type of integral firestopping might makes sense when PC is
> > used
> > > in a wall to limit the spread of the smoldering, since
ultimately
> > the
> > > block was consummed. To play it safe, I believe that the wall
> > > surface should be coated with a plaster or gypsum product to
> > prevent
> > > the smoldering from starting. Here is a link to pictures:
> > > http://www.domovitae.com/fcrete/pcfire.htm
> > >
> > > food for thought - Duane.
> > >
> >
>
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