Eric Olson on wed 15 mar 00
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I am building a 90 cu. ft. flattop car kiln, to fire stoneware to cone 10 in
moderate reduction (no copper reds). I have two 400,000 Btu nat. gas power
burners recommended and built by Mark Ward, and the walls are 6=22 of fiber
sprayed with ITC 100, and ITC 296-A. Burner ports are 4.5=22x6=22, and the =
flue
exit is 7=22x10=22. I built a fluebox similar to the one Nils Lou uses =
(adjustable
damper), with the exception of the double venturi system i.e. 5 5/8=22x5 =
5/8=22
opening going into the metal chimney pipe, mine is 9=22 x9=22, and small =
flue exit
(4 1/2=22 x 9=22) opening coming out of the kiln, mine is 7=22 x 10=22. The=
height of
the flue box would be about 6 1/2 feet, that is, 4 feet of hardbrick chimney
above the damper slot, and before the metal pipe starts.
I have located triple walled, 10=22 ID pipe, made by Simpson Duravent, =
which is
temp rated to 1000 F continuous, and 1700 F intermittant. The clearance on =
this
pipe is 2=22 to combustibles within those temp ratings. I should have 3 =
1/2=22
clearance from the outer diameter of this pipe to the roof trusses. I have =
to
go through a combustible ceiling, since the city requires that a kiln be in =
a
building which is attached to my house. I know...this doesn't make sense to=
me
either, but there is no other way I can do this. I will be coating the =
inside
and outside of the pipe with ITC 213, and spraying the inside of my roof,
including the trusses with ITC 100 just to be safe. If need be, I can also =
wrap
the pipe with fiber blanket for more protection.
Can anyone shed any light on the flue gas temps entering the metal chimney =
pipe
from the fluebox/brick chimney? Does this sound like a safe installation? =
The
city has agreed to =22go along with whatever industry says will work=22, so =
my main
concern is safety, and not burning my house down. Nils also said that =
adding 3
or 4 COURSES of hardbrick above the damper slot should cool the gases to =
1200 F
to 1400 F before entering the metal pipe. Since I added 4 feet, I thought =
that
the gases would be cooled even more. Someone else also suggested that I =
leave a
small gap between the brick and the metal pipe to suck air in along with the
gases.
Any help would be greatly appreciated. I have been searching for answers on
this for about a month, and while alot of people have set-ups that work =
great
for them, none of them have the same situation as mine.
Thank You
Eric
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