Great Article Duane. Thanks!
Please post that one in the links section.
I learned a lot. Not only did it help me better understand what
borates do and how they do it, but it has helped me forumlate better
questions in my mind. There's a whole slew of other questions that
I've tried to find answers to that I didn't know enough good search
terms for in Google.
For example:
I'm off to learn exactly how a "Fire Tube Test" works.
I also need to learn about "Heat release rate calorimeters."
Both sound like fun!
I knew some better tests had to exist than pointing a torch at a
sample and sitting around to see what happens. Now I can learn what
the pros do and see if I can come up with my own budget version.
You're full of good info. Keep it coming.
I'm full of stuff too, but that's another story.
--- In papercreters@yahoogroups.com, "mdumiller" <mdmiller1@...>
wrote:
>
> 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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