John Baymore on mon 6 nov 00
I just read the newspaper today that the gas kilns I built and fired for =
6
years caught the roof on fire at the university. The fireman said the
chimney wasn't built to withstand high temperatures-news to me! The part=
time instructor said that some work had been done on the roof last summer=
..
I am thinking that maybe tar caught on fire. Another possibility was tha=
t
there was too much gas with an open damper and it was heating the chimney=
and not the kiln.
As a kiln consultant I run into this kind of stuff periodically.
The "standard of the industry" kiln chimney seems to be a 4 1/2" thick wa=
ll
of hard firebrick in site built kilns. Is that what this one was?
That type of kiln chiminey construction works OK as long as it works OK
. Kidding.... but that is sort of the issue. If you look at things=
like NFPA and BOCA codes.... they have very specific construction
specifications for medium and high heat appliances. 4 1/2" of hard brick=
is NOT typically it . If your kiln chimney does not conform to these=
regs......... AND you are in a location in which the codes ARE in
effect...... then the fireman was correct....... your kiln chimney is no=
t
"..... built to withstand high temperatures". =
If you are playing in their game you have to abide by their rules . =
To illustrate a bit....... I'll include part of a typical "code" listing
here for a local New England state:
A kiln would be specifically defined by the code as what is referenced as=
a
"high heat appliance". For masonry high heat appliance chimneys,
construction is specified as a double walled masonry construction with a =
2"
dead air space between the exterior and the interior lining, with the
interior lining being of no less than 4 1/2" of refractory brick (per AST=
M
C64) laid in refractory mortar. The chimney must be fully lined, bottom =
to
top. It must terminate not less than 20 feet higher than any portion of=
any building within a 50 feet radius.
If the state code above applys....and a kiln chimney is not done this
way..... it is out of compliance. This can cause real issues to arise in=
the event of a problem.
Unfortunately, true "code" chimneys and roof penetrations can get sort of=
expensive. I have done some installations in some jurisdictions where du=
e
to the building geometry, the chimney structure cost more than the kiln
itself. Contiguous chimneys (NOT having a "break" in them pulling in
diluting cooler air) are the most difficult issue in this regard. =
To generalize a LOT........ typically the more institutional and the more=
urban the kiln installation.... the more often the kiln chimney is looke=
d
at by regulators as having to complying with "code". I often can't do in=
a
school type situation what I can do for a private potter. Just the way i=
t
is.
When there is an actual fire...... THEN they are looking at all the
details of the installation.... (barn door and horse anyone) and often
catch something that they actually let "get by" in the first place. It i=
s
sort of like the electrician looking in the electric kiln peep hole and
saying "I didn't realize that it got THAT hot!"......... after he tried t=
o
skimp on the wire size . In many cases when gas kilns are put in....=
...
no one involved from the town knows how to correctly classify the unit fo=
r
code purposes.... and so it never gets looked at in reference to the
possible applicable codes. It is "arty", and unique, and uncommon, and s=
o
it sometimes gets looked as somehow "outside" the codes....even if it =
actually IS listed in the codes. Which is in most cases a GOOD thing! <=
g>
Because otherwise many kiln installations would get tied up in tons of r=
ed
tape and rapidly increasing costs. Or regulated right out of existance.=
But sometimes it can come back to bite you in the butt after a problem
arises. =
If the university's roofer treated the kiln chimney as he/she would a
"rated" (to code) chimney....... he/she would never have expected the
temperature on the exterior of the brick structure to reach a level that
would cause a problem with "standard" flashing, clearances to combustable=
s,
and normal sealing techniques. So the "roof work" comment could easily =
be
the root cause of the problem. Maybe they tightened up the penertation
point, some tar started oozing down the chimney and eventually it caught =
on
fire.
Also different firepersons can put differing amounts of heat up the chimn=
ey
(read that as wasted heat ). If the chimney installation was a "fire
waiting to happen" that level of wast heat could "push it over the edge".=
=
Wood gets more flamable as it is repreatedly dried out and partially
pyrolized by being exposed to high levels of heat. Roof penetration fire=
s
ususally do not occur on the first firing....but after a number of firing=
s.
The typical 4 1/2" of hard brick kiln chimney solution has a record of
working pretty well in private studios where the potter has a good
understanding of the heat that the exterior of the bricks give off....and=
who builds the roof penetration to deal with this fact. If the roof in
that case is being redone..... the potter is either doing it him/herself =
or
is directly telling the roofer exactly what to do. However, in a
school....... things often get done without anyone knowing they are being=
done. Outside contractors or maintenence people don't always communicate=
effectively with the faculty or technician (and vice versa). Provides
opportunity for problems .
Best,
.....................john
John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA
603-654-2752 (s)
800-900-1110 (s)
JBaymore@compuserve.com
John.Baymore@GSD-CO.com
"DATES SET: Earth, Water, and Fire Noborigama Woodfiring Workshop =
August 17-26, 2001"
Marcia Selsor on mon 6 nov 00
John,
It is not my problem. I forwarded it info to the current instructor. I
am retired and with just cause.
The chimney had a ceramic flu liner and insulation bricks NOT hard
bricks. It was 2-4 inches away from combustibles so I don't know what
happened unless the roofers did something. I haven't been there for 6
months. I wish to remain working in my studio and not answering phone
calls from people who were hired to do the job.
When I was hired 25 years ago all the males students dropped ceramics.
(Montana men!) I had to rebuild the two stoneware kilns without pay by
coming a month early to start my job. The door of one kiln had fallen
over at ^10 while I was there for my interview. I ran that program for
25 years without incident. In 1980 we moved into newer facilities due to
my greivance regarding health and safety issues. At that time the
contractor and the Director of Facilitiy Services refused to consult
with me regarding the ceramics needs. I was given a grade c appliance
chimney to connect the kilns to. This is for water heaters. I told them
I refused to connect kilns to that and finally got a heat resistent
$4700 steel monstrousity not the bricks I requested- this is at an
institution that had an annual budget for ceramics go from $350/year
down in 1980 to $150/year by 1999. When I returned from a second
sabbatical I had to rebuild the kilns in 1994 with no budget. By the
grace of God, there had been an 20 year accounting error in the
bookstore that gave the art dept. $18,000 of which I got about $700 for
bricks -which I had to unload!. We finally got rid of that monstrousity
and put in individual chimnies. We fired those kilns several times /week
for the past 6 years. So what happened? Maybe the wood finally got too
dry or maybe too much heat up the chimney ot the tar?
It is out of my hands and I am really happy about that. Did I mention
cut backs of no assistant from a full time one in 1980-1984? I have
physically suffered from that place ( 3 workers comp injuries including
bilateral carpal tunnel which I blame on the two hard brick doors I
inherited in 1975 equivalent to 1600 pounds per firing.) and lack of
support so I really don't give a damn anymore and, yes, I am bitter. I
have my own kilns and studio and I am very happy with them.
Sorry if this is too bitchy. but I don't want anything to do with that
place. I am glad I made it to my pension.
Marcia
John Baymore wrote:
>
>
> I just read the newspaper today that the gas kilns I built and fired for 6
> years caught the roof on fire at the university. The fireman said the
> chimney wasn't built to withstand high temperatures-news to me! The part
> time instructor said that some work had been done on the roof last summer.
> I am thinking that maybe tar caught on fire. Another possibility was that
> there was too much gas with an open damper and it was heating the chimney
> and not the kiln.
>
>
> As a kiln consultant I run into this kind of stuff periodically.
>
> The "standard of the industry" kiln chimney seems to be a 4 1/2" thick wall
> of hard firebrick in site built kilns. Is that what this one was?
>
> That type of kiln chiminey construction works OK as long as it works OK
> . Kidding.... but that is sort of the issue. If you look at things
> like NFPA and BOCA codes.... they have very specific construction
> specifications for medium and high heat appliances. 4 1/2" of hard brick
> is NOT typically it . If your kiln chimney does not conform to these
> regs......... AND you are in a location in which the codes ARE in
> effect...... then the fireman was correct....... your kiln chimney is not
> "..... built to withstand high temperatures".
> If you are playing in their game you have to abide by their rules .
>
> To illustrate a bit....... I'll include part of a typical "code" listing
> here for a local New England state:
>
> A kiln would be specifically defined by the code as what is referenced as a
> "high heat appliance". For masonry high heat appliance chimneys,
> construction is specified as a double walled masonry construction with a 2"
> dead air space between the exterior and the interior lining, with the
> interior lining being of no less than 4 1/2" of refractory brick (per ASTM
> C64) laid in refractory mortar. The chimney must be fully lined, bottom to
> top. It must terminate not less than 20 feet higher than any portion of
> any building within a 50 feet radius.
>
> If the state code above applys....and a kiln chimney is not done this
> way..... it is out of compliance. This can cause real issues to arise in
> the event of a problem.
>
> Unfortunately, true "code" chimneys and roof penetrations can get sort of
> expensive. I have done some installations in some jurisdictions where due
> to the building geometry, the chimney structure cost more than the kiln
> itself. Contiguous chimneys (NOT having a "break" in them pulling in
> diluting cooler air) are the most difficult issue in this regard.
>
> To generalize a LOT........ typically the more institutional and the more
> urban the kiln installation.... the more often the kiln chimney is looked
> at by regulators as having to complying with "code". I often can't do in a
> school type situation what I can do for a private potter. Just the way it
> is.
>
> When there is an actual fire...... THEN they are looking at all the
> details of the installation.... (barn door and horse anyone) and often
> catch something that they actually let "get by" in the first place. It is
> sort of like the electrician looking in the electric kiln peep hole and
> saying "I didn't realize that it got THAT hot!"......... after he tried to
> skimp on the wire size . In many cases when gas kilns are put in......
> no one involved from the town knows how to correctly classify the unit for
> code purposes.... and so it never gets looked at in reference to the
> possible applicable codes. It is "arty", and unique, and uncommon, and so
> it sometimes gets looked as somehow "outside" the codes....even if it
> actually IS listed in the codes. Which is in most cases a GOOD thing!
> Because otherwise many kiln installations would get tied up in tons of red
> tape and rapidly increasing costs. Or regulated right out of existance.
>
> But sometimes it can come back to bite you in the butt after a problem
> arises.
>
> If the university's roofer treated the kiln chimney as he/she would a
> "rated" (to code) chimney....... he/she would never have expected the
> temperature on the exterior of the brick structure to reach a level that
> would cause a problem with "standard" flashing, clearances to combustables,
> and normal sealing techniques. So the "roof work" comment could easily be
> the root cause of the problem. Maybe they tightened up the penertation
> point, some tar started oozing down the chimney and eventually it caught on
> fire.
>
> Also different firepersons can put differing amounts of heat up the chimney
> (read that as wasted heat ). If the chimney installation was a "fire
> waiting to happen" that level of wast heat could "push it over the edge".
> Wood gets more flamable as it is repreatedly dried out and partially
> pyrolized by being exposed to high levels of heat. Roof penetration fires
> ususally do not occur on the first firing....but after a number of firings.
>
> The typical 4 1/2" of hard brick kiln chimney solution has a record of
> working pretty well in private studios where the potter has a good
> understanding of the heat that the exterior of the bricks give off....and
> who builds the roof penetration to deal with this fact. If the roof in
> that case is being redone..... the potter is either doing it him/herself or
> is directly telling the roofer exactly what to do. However, in a
> school....... things often get done without anyone knowing they are being
> done. Outside contractors or maintenence people don't always communicate
> effectively with the faculty or technician (and vice versa). Provides
> opportunity for problems .
>
> Best,
>
> ....................john
>
> John Baymore
> River Bend Pottery
> 22 Riverbend Way
> Wilton, NH 03086 USA
>
> 603-654-2752 (s)
> 800-900-1110 (s)
>
> JBaymore@compuserve.com
> John.Baymore@GSD-CO.com
>
> "DATES SET: Earth, Water, and Fire Noborigama Woodfiring Workshop
> August 17-26, 2001"
>
> ______________________________________________________________________________
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>
--
Marcia Selsor
selsor@imt.net
http://www.imt.net/~mjbmls
http://www.imt.net/~mjbmls/spain99.html
http://www.silverhawk.com/ex99/selsor/welcome.html
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