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Re: GSBN:fire test -- your opinions?



Bruce -

I communicated with you about the fire tests a month ago, but with some new
information I will express my latest opinion, and offer some thoughts to the
GSBN people.

If I had to pick one wall, two-string bales laid flat with cement-lime
plaster is definitely the right choice in my opinion.  Regarding no mesh, I
think I see the point, but worry that without the mesh some sections of
plaster might pop off the bales under intense heat and cause a major failure
in the test.  Is this a real possibility or just my imagination run amok?

You are now able to conduct two tests, which is great, and thanks to all who
contributed to allow it to happen.  So . . .

Previously I advocated that bales on-edge be tested (to test for the effect
of presumed melting/popping polypropylene strings among other things, and to
satisfy the many on-edge practitioners (maybe we are a bit on-edge)), but
not far behind that is my strong desire to see clay based plasters tested.
For the many practitioners who use earthen plasters (some exclusively), and
the direction it seems to be heading.

I wonder if there's a way to have it all with two tests.  Assuming the walls
will be approximately 8'x8' (6.2mx6.2m) can you:

A) Have a cement-lime wall with half of it laid flat and half of it on-edge
(I ask this without knowing the dimensions of the bales you will use), and
then have the other wall laid flat with clay plasters. (or the reverse)

OR

B) Test the first wall as you have it, and test the second wall with bales
on-edge and with clay plaster.

'A' might present some construction and protocol problems.  With 'B', I
suspect both tests would be successful (for 2 hour) and thus we could have
it all.

If clay plaster is used I assume you would use no mesh (potential spalling
problem?) and I'm wondering what thickness you would use.  1 1/2"? (3.8mm).

Also, will the test be done in accordance with ASTM E119?


Martin Hammer (and The Melting/Popping, Polypropylene String Band)
California



>
> Everybody --
>
> An ASTM fire test will be conducted this summer in San Antonio, Texas
> on two different wall types.  After much thought and discussion with
> David Eisenberg, and many baleheads at the recent CASBA 10th
> anniversary celebration, the tentative wall types are two-string Texas
> wheat bales---one with bales flat, and one with bales on edge---both
> with no pins or mesh, and both with two coats of lime-cement plaster.
>
> If anyone feels strongly that we should test some other assembly,
> please do speak up;  David and I both feel that this is too important
> for us to decide by ourselves.
>
> John Glassford and others have suggested earth plaster, sensing that it
> may outperform lime or lime-cement.  And you may well be right, but in
> the current and foreseeable building environment, the people who will
> need a fire rating for their building (I suspect) will also need the
> higher hardness and durability of lime-cement.
>
> Any comments?
>
> Thanks!
>
> Bruce King, PE