Venting of Electric Kiln question??
Zander
I'm new here and to pottery in general. My wife is a potter and I am in
the process of building her a pottery studio in our basement workshop.
This room is pretty well sealed from the rest of the house.
I have a round electric kiln. I want to find out about ventilation of this
kiln. I have read that noxious fumes are created both in the bisque firing
and the glaze firing. I have acquired an truncated aluminum cone with a
hole in the top used to suspend over the kiln - lowered by means of block
and tackle.
I have 2 options for venting to the outside.
One is straight across the ceiling to the exterior wall, punch a whole
through masonary block, install rigid 4" dia. duct with an inline fan and
run it outside with maybe an elbow pointing up and a rain cap. I don't
like this idea too much because the fumes will exhaust essential at ground
level and then just drift around.
Second option is to tie into and existing duct chimney that is used by my
gas fired hot water heater, this is a double walled chimney that goes all
the way through my house and out the roof. It is also only about 6 feet
from the kiln. If you have a gas fired hot water heater you may be
familiar with the gap between the duct and the tank. This concerns me a
bit if any kind of back draft occured. Also, would it be ok if they both
were working at the same time?
Keep in mind I have no idea how much fumes to expect from this kiln. Is
there a rule of thumb for CFM of ventilation? Any advice would be
gratefully received...
Thanks
Zander
Steve Mills
ideal for fume extraction, either into a chimney or out of a window or
whatever; heat from the kiln will warm it up, and provided it is
pointing upwards it will then *draw* like any good chimney, self
extracting fumes from the area. In the UK all kilns including top
loading drum kilns have to have a vent hole in the lid or roof. We
position the flue liner over the hole, but have to take care that we
don't get it too close (about 4 inches is right). If we did it would
draw a lot of the heat out of the kiln!
Steve
Bath
UK
In article <Xns94857B88D4BA...@216.40.28.70>, Zander
<nom...@no.com> writes
--
Steve Mills
Bath
UK
Zander
Thanks for the info. My Kiln has no hole in the lid, the only holes it
has at all are a couple of tiny sight holes in the side. Makes me
wonder how the fumes escape at all?
Zander
Steve Mills <St...@mudslinger.demon.co.uk> wrote in
news:qn2rKWA4...@mudslinger.demon.co.uk:
wayneinkeywest
You are correct...DO NOT vent the kiln vent into the stack
(chimney) for the water heater. It can cause combustion
fumes from the water heater to backflow into your living
space and the carbon monoxide can kill you in your sleep.
In most places in the US, the practice of doing so is illegal
and against building codes.
Kilns are not sealed units. Some air is going to flow in and
out of the peepholes (sight holes) in the side of the kiln,
and additionally in the small gaps between the kiln lid and sides.
Some kiln manufacturers recomend drilling 4 or 5 small
1/4 inch (6mm) holes in the center of the bottom of the kiln,
and again in the top, but I have never found it necessary.
Just remember to leave the vent fan running until the kiln is
at room temperature after the firing to get rid of any noxious
fumes. It costs a couple extra cents to run the fan,
but it can save your family's lives. What's that worth?
As Steve suggested, positioning the hood about 6 inches
from the top of the kiln is about the right distance, depending
on the size fan you are using. Most newer kiln hood vents
run about 265-300 cfm (cubic feet per minute), and I've seen
them mounted as far away as a foot and a half (0.5m) You will
have to experiment some to find the ideal conditions for you.
If you can smell fumes, the fan is not doing it's job, and
may need to be closer or more powerful. A carbon monoxide
detector is relatively inexpensive "insurance" against a problem.
Believe me, it will let you know if there's a leak :>)
You can get one at any home improvement store like Home Depot
or a hardware store may have it. You can also get them online.
Last but not least, make sure there is a source of INCOMING
air for both the water heater and the kiln vent. You don't want
to create a situation where the air that is being exhausted is
being replaced by water heater emissions (backdraft).
Hope that helps,
Wayne Seidl
"Zander" <nom...@no.com> wrote in message
news:Xns94858B372DF4...@216.40.28.70...
Zander
That helps a lot! Thanks. If I can pester you for a few more details
that would be great.
I plan on connecting my hood to a small block and tackle to lower it
over the kiln. I will connect flexible aluminum duct from the hood to
the ceiling where I will connect it to rigid 4" dia. aluminum duct. I
will run this to the wall and then outside.
My two questions are;
What should I do outside? Is it ok to vent at ground level? Or should
I run the pipe all the way up to the roof line?
And, what kind of fan should I get. They sell in-line duct fans here
that are really meant as 'boosters' or do I need something more serious?
Thanks again for any advice.
Zander
"wayneinkeywest" <waynein...@bellsouth.net> wrote in
news:7EcUb.5558$uS3....@bignews4.bellsouth.net:
wayneinkeywest
aluminium (not plastic...remember...heat!)"dryer vents".,
Depending on where you live, you might want one that
keeps critters out. If it is truly at ground level, like _right_
on the ground, you might want to put an elbow and raise it
\three or four feet to keep it out of the snow, if you have any.
Take a look at how your dryer vents, and do roughly the same thing.
You do NOT have to go right to the roof line. I doubt anyone is
going to be out there with their nose stuck in the vent. If your
neighbors are VERY close to that side of the house,
run the vent (over the top and) into a plastic bucket on the ground that is
filled with
water, with the vent pipe sticking into the water. Just
remember to change/add water occasionally. Passing the kiln
gases through the water will help filter anything harmful out.
That's not foolproof though, so don't try that inside! I know it's not
easy chopping concrete. Maybe there's a cellar window nearby
that a glass pane can be removed from to send the pipe outside?
Alternately, you can bury the bucket so the top is _just_ at ground
level, and run the vent line into it from the top. With that, though,
you have to be careful nothing falls in, like small animals or kids,
or tries to drink the water... like small animals or kids :>)
For the vent fan, look at the CFM rating on the fan itself. You will
want something with at least 250 cfm. More than a bathroom fan
vent. You might have to special order it. Check with manufacturers like
Broan or Nutone. I don't know how long a "run" you have planned
for your piping (in feet/meters). Obviously, the longer the distance
the stronger the fan should be. Don't worry about getting one too strong,
as you can always raise the vent hood further from the kiln.
If you're going to use an "in-line" fan/booster motor, place it in the
line just at the wall going outside, to give the heat a chance to cool a bit
before
sending it through the motor, keeping the motor inside, and out of the
weather.
I've seen the motors mounted right on the hood itself, and they don't seem
to hold up as long. (Duh! sitting on top of 2300 degrees
which is being sucked into an electric motor?!)
Hope that helps,
Wayne Seidl
> What should I do outside? Is it ok to vent at ground level? Or should
Steve Mills
extractor fan which we can call *pushers* or *pullers*. Pushers don't
pull very well and vice-versa. As a pusher would be, as Wayne said, in a
bit of a hot spot, it would probably be best to use a puller type as
close to the outside wall as possible. There are exterior mounted ones
available, I know because we're having one set up as the kitchen stove
extractor; we're fed up with being deafened by the one in the cooker
hood!
Steve
Bath
UK
In article <ZSeUb.4079$Rl4....@bignews5.bellsouth.net>, wayneinkeywest
<waynein...@bellsouth.net> writes
--
Steve Mills
Bath
UK
wayneinkeywest
going to be a puller, not a pusher. Also, here the "powers that be"
discourage the use of outside fan assemblies, except in commercial or roof
applications, citing noise complaints from
neighbors.
The last thing they need is a nosy inspector, which is why I suggested using
a dryer vent type exhaust. Easy enough for the inspector to spot and think
"oh, that's a dryer" and let it pass :>)
The ever devious
Wayne Seidl
"Steve Mills" <St...@mudslinger.demon.co.uk> wrote in message
news:$8vecQAd2YIAFw$h...@mudslinger.demon.co.uk...
Brad Sondahl
by venting, it has to come from somewhere, and can conceivably come from the
vent for the water heater, also creating a Carbon Monoxide hazard. That
happened to us when I was apprenticing-- got a squirrel cage fan to vent the
kiln room, and it sucked Carbon Monoxide from the furnace flue and gave us
headaches--took awhile to figure out what was happening.
To prevent it you would need to bring in a vent of fresh air into the kiln room
equal in size to the vent going out.
Also I have a little venting system outlined on one of my webpages.
Brad Sondahl
For original art, music, pottery, and literature, visit my homepage
http://sondahl.com
Pottery sales page http://sondahl.freeyellow.com
To reply to me directly, don't forget to take out the "garbage" from my address.
Zander
I talked to the local pottery store today to cost out existing kiln vent
systems like orton and bailey. He told me that the cone type suspended
vent that I was looking at isn't recommended because it is isn't as
effecient at removing fumes. He suggested the direct kiln vent which he
says is better. Makes sense too I suppose. Apparently you need far less
CFM because you really only want a negative pressure in the kiln, so not
enough to remove all the heat. He said you can keep the cone suspended if
you wish to vent heat out of the room in the summer etc. This has thrown
all of my plans into chaos! I will have to think about all of this....
Zander
"wayneinkeywest" <waynein...@bellsouth.net> wrote in
news:hohUb.9177$qK3....@bignews3.bellsouth.net:
Steve Mills
In article <hohUb.9177$qK3....@bignews3.bellsouth.net>, wayneinkeywest
<waynein...@bellsouth.net> writes