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permits for gas kilns - advice? (long)

updated thu 21 jun 01


John Baymore on wed 20 jun 01


Hi. Here is a copy of a posting I did a long time ago to another similar=

CLAYART question. Thought some of it might be helpful in your current
case. I will have another one too that has a few different twists too
following this one.



----------------------------Original message----------------------------

Would someone who has had experience with this situation be
willing, in the next day or two, to help me with this? ............ The
kiln will be about 50 cubic feet, perhaps a Minnesota flatttop, perhaps a=

catenary arch, gas-fired, cone 10.

Glad to ..... on occasion, I do this stuff for people.

--Whom do I need to contact in order to install a kiln in a residentia=
neighborhood? The fire marshall? Zoning office? Building inspectors?
EPA? Insurance company? The neighbors, to see if they would consider it=

Hate to say it but ............ possibly "yes" to all of the above.
Eventually. So much depends on the specific TOWN and it's level of
bureaucratic and legal awareness and desired level of control over what
happens within its borders. Generally speaking, the more urban the
location, the more regulations and permits you will have to have, the mor=
rural the less. The more urban the location the more the installation wi=
cost.... the more rural the less.

The first level to look at in your endeavor is the mayor's office/
selectmens office. They know what is allowed in what districts in town a=
what the procedures are for doing things. If they say a broad "yes" to
the general concept then the rest is a matter of formalities on the
of the installation that you can get into after you buy it. If they set =
hurdles you have to jump through, then you have to decide if the hurdles
are "iffy" enough that you don't want to take the gamble.

As a generalization....which is ALWAYS a bad thing to do.........:
Residential A is usually OUT most everywhere..... it is usually NIMBY cit=
Your kiln will probably be looked on as the thing that will bring proper=
values down in the entire neighborhood . Even Res. B ( allows some
non-residential uses) is often a problem. Places that allow agricultural=

along with residential are usually better. Liberal home occupations zone=
are OK.... tightly restricted ones (professional offices only) are usuall=
out. Rural areas are almost always the best.

If pottery and gas kilns is important in your life, then your housing
location decision should take that into account. You may have to give up=

the typical suburban RES. A district for the sake of the kiln. Not for
sure.... there are certainly gas kilns located in Res A districts........=
but it is possible.

So the first place to check is the town offices. Find out what they have=

to say about your idea of being a potter in that particular neighborhood.=

Be open about it.... don't hide any of it. Describe the full reality.
Will you sell out of the studio? Will there be a sign? Will trucks
deliver materials? How much production do you anticipate? Will UPS be
doing regular pickups of shipped pots? All that stuff.

Get all this stuff out in the open. You are investing a lot of money in
moving there and you want to be able to do what you want. If you hide th=
facts.... then you can get nailed after the fact and end up in a battle..=
or not being able to run the pottery business and being stuck there. The=
having to re-locate again.

Guage the response from the main town office as 1.) warm 2.) indiferent
3.) hostile. If you get number 1, that's great. Number 3 probably says
look at another piece of property. Number 2 is more typical.... and will=

require you to do some digging.

Ask if there are any other potters in town with gas fired kilns. If ther=
is, go visit him/her and find out what they went through getting the kiln=

in. They are your greatest asset. They can tell you who is supportive a=
who is the "bad guy". They'll know who is knowledgeable on the subject=
They'll know where they made mistakes in the installation itself, or in h=
they went about getting it. See how their property compares to your
proposed site in regard to zoning, population density, and the like, and
draw some conclusions about the applicability of what they experienced to=

your situation.

Sometimes this "installing large kilns thing" ('d probably have=

similar issues if you installed a 50 cubic foot electric kiln) is a real
issue when buying a site to open a pottery. Permits and variances and th=
like usually go with the owner, not the property. So as a non-owner you
can't go before the town officials and get a permit....only the owner of
the property can get that. But the existing owner will sell the property=

to you...... and the permit or variance does NOT usually transfer from
them. So sometimes this situation is the old .....pig in a poke. Buy it=

and then see if you'll get the permits.

The best situation is one in which you pretty much KNOW you have as many =
the variables going in your favor as possible. Then it is a worthwhile
gamble. Talk to the town officials that will have to make the decsions..=
guage their responses. Decide on the "gamble factor".

If you are doing this as STRICTLY a hobby, then you have one hurdle out o=
the way. As a hobby, many issues of town zoning laws that apply to
businesse or home occupations don't apply. Basic building codes (if ther=
are any) ALWAYS apply.

If you are selling your work, then the first order of business is to make=

sure that the property is in a zoning area that allows home occupations (=
actual businesses) without a permit or variance. If that is the case,
check the laws and make sure that certain emissions of "noxious
elements" is not included in a list of things you can't do....... could
come =

back tobite you if a neighbor doesn't like the kiln . A potters kiln=

of =

the 50 cubic foot size COULD be looked at as an "industrial furnace" by =

those not predisposed to look kindly on such things.... and come into
with the list of things thjat produce "noxious" stuff.

Watch for clauses in the home business section about not having exterior
equipment or materials showing. That could preclude an outdoor kiln or
even a separate kiln shed.

The gas inspector and the building inspector (if there are any) will get
involved at some point cause they have to approve the final installations=
This would be after you have the property. You can usually get
approvals........ it just is the cost associated in making them happy tha=
is an issue. Since there are few jurisdictions that have specific
regulations naming "gas fired pottery kilns" on the books......... each
kiln installation can be open to pretty WIDE interpretation of exactly HO=
it must be installed.

That is both a blessing and a curse.

Whatever you do DON'T let anyone classify it as an industrial furnace.
There ARE regs for those and they are COSTLY. Prohibitively so. It is
simply an artist potters kiln. That will baffle them in searching for
printed regs . Ain't none. SO........ that leaves YOU (or another
potter) as the expert on artist potter's kilns. Then you can tell THEM a=

lot of how it should be installed.

Do your homework and put on a professional presentation and you'll probab=
not have too much of a problem. Let each inspector have their little
"suggestion" be added into the plans...... they like to feel that they
did their jobs........ and away you go. If you are clever you'll ask a
question or two for their suggestion that addresses an area that won't be=

too costly to follow their advice...... whatever it is. That way YOU
channel what they suggest instead of letting them FIND a place to make
changes (for lots of money). If you are really good at this... you'll
channel your questions to get them to recommend exactly what you planned =
do in the first place .

It is always a good idea to talk to the potential neighbors. If they are=

supportive then you will have few problems. If they aren't, even if you
are "legal" than they will be a constant source of irritation and will
eventually find a way to shut you down. Show them pictures of your
proposed type of kiln and what it will look like. Explain what you do.
Show them your pots. Again...... guage their reception.

As to the EPA stuff..... that would be after the fact if at all. It is
little known.............. but if you are running a pottery business, in=

many locales if the kiln is large enough you do need both an EPA
installation permit and an annual operating permit. Has to do with aIr
quality standards in questionable air districts. Call the local EPA
office....... they're in the phone book. Few people get these permits an=
to my knowledge the EPA does not go looking for craft type potters. They=

have bigger fish to fry. However, if a complaint is ever filed with them=
then you get in hot water for not having the permit. Generally not one t=
be too concerned with.

--If I'm asked what will be coming out of the chimney, what's the

The vast preponderance is simply hot colorless carbon dioxide and water
vapor, with occasional small amounts of carbon monoxide during parts of t=
firing cycle (don't play this up too much, and omitt completly it if you
fire in oxidation or feel comfortable not telling the whole truth).
Occasionally you will see some thin light vaporous steam off the chamber
and off the chimney. No significant smoke ever from a gas kiln (if it is=
you are firing wrong). Yes.... there are traces of many of the glaze
chemicals in the effluent.... but these are so small that I'd not mention=

it unless someone gets VERY specific....... and if they are getting THAT
specific...... you should abandon looking at buying that site.

--What questions should I ask at the local gas company (and what are t=
"right" answers), about, say, the size of the gas main in the street? =3D=

need for an additional line (size?) from the main to the kiln and a heavy=

duty gas meter? The pressure, energy content, and flow rate of their gas=

The right answers are ..... "Sure no problem...... we've put in a few =

kilns in this town and know how that stuff works. We like potters. Did
you know
that the gas inspector and the fire marshall in town are both potters?
Fire marshall has a big anagama. Building inspector does large scale rak=

Ask enough questions that you sound like you know what you are doing.....=

not so many that you seem inexperienced. Sounds tough, I know.

Ask if they handle any other gas fired ceramic kilns in town. Ask what
requirements they have for such a unit as to flame safety systems. Ask w=
the gas inspector is.

The gas company's job is to know gas supply. You tell them what you need=
they'll tell you how to get it and how much it'll cost. They LOVE to tel=
you how much it'll cost . Propane is about 2500 BTU's per cubic foot =
STP....natural is about 1000 BUT's.....but that info in this situation is=

not really important. You figure your needs in BTU requirements....they
figure how much gas you need.

For a 50 cubic foot kiln of IFB, you'll need about 500,000 BTU's of fuel
available at peak draw..... and you'll never really use this. This is th=
"rule of thumb" design figure generally used to figure gas requirements f=
this type of kiln. Even if you ever reach that typical design limit in
draw (which I doubt)'ll be for a very short period... maybe 1 hour=
Most of the cycle will be well below this.

So you TELL them you need this absolute maximum BTU volume input. They'l=
tell you if, and how, you can get it supplied at your site. And what it'=
cost you .

Watch certain code regulations....... at 500,000 BTU's input on natural g=
in some locales, this places the kiln in a bracket that requires a double=

block system on automatic safety valves.......... gets expensive and
complex. Redundancy in the safety system..... costs $ and adds
electronics. Complexity. Not good. In this case, use 480,000 BTU's as
the design value to get around the requirements.... no real significant
impact on kiln operation.

Propane is no problem for any practical maximum draw......... and for a
kiln that size you'll need a MINIMUM of a 500 gal. tank, unless you go wi=
liquid withdrawal burners, or with a liquid withdrawal evaporator to
convert liquid to gas (not recommended......for technical and $ reasons).=

If you go propane, use vapor withdrawal burners for simplicity and cost.
I'd recommend a 1000 gal. tank for that size kiln, particularly if you ar=
in a colder climate area..... so you don't have problems with vaporizatio=
in the cold winter months.

Propane storage tanks require certain setbacks and clearances to
structures. Make sure the property supports these without variances. So=
towns require propane storage permits for tanks. Usually a rubber stamp
issue once the installation to use the gas is approved. Some neighbors
don't like large propane tanks . Might want to bury it for aesthetic
reasons to keep the neighbors happy.

If it is natural gas, and there is not a main nearby, they'll want to
charge you for the mains extension. Lots of $ generally. Probably want =

to skip that option altogether.

If you have natural onto the property, and the line has to be upgraded in=

diameter to meet the flow requirements from the street, you'll have to
negotiate who pays. It is their job to know the line size. The meter
often needs to be replaced with a larger capacity unit.... again negotiat=
who pays. Remember the joint capacity of the house and the kiln...... bo=
have to be supplied off the main line. Get separat4e meters for tracking=


If the property has natural on the site, but the volume in the mains will=

not support both the kiln and the house load, you might opt for propane o=
the kiln leaving the house on natural. However, in many locales this
requires a special "dual fuel" permit be pulled for the property .....
usually from the fire marshal or the fire dept. Sometimes from the
building dept. Some places won't allow it at all.

As to pressure........ you can fire a kiln on ANY pressure. You just hav=
to design the combustion system to work with that. Volume is the issue,
not pressure. On low pressures, you need to supply air by mechanical
means. The gas pressure will not be useful to entrain the necessary air.=

No big deal. Does add some cost though.

If on natural, plan on low pressure, 4 - 11 inches water column, as typic=
pressure unless you are in an industrial area, and plan on using forced a=
burners. If you have higher.... still go with forced air burners and low=

pressure. If on propane, you can use low pressure and forced air burners=
or go with high pressure at least 5 pounds sq. in. g. venturi
burners and skip the dependance on electrical energy links. High pressu=
venturis (good industrial quality ones) entrain more percentage of primar=
air than low pressure ones, and hence give you more options on air handli=

Avoid all low pressure venturi burners or the cheap one piece cast
burner/retention nozzle units even for higher pressure......... poor air
handling capacity.

Keep in mind that with forced air burners there will be some roaring
noise........ that might affect the neighbors late at night. Even ventur=
burners operating at higher pressures roar. At 2 AM, they all seem loud.=

ANmd the glow from the open port burners seems awfully bright at 2 AM too=
Some people would find this to look very hazardous..... check the

As to getting around code and nervous town officials...... if things get
rough you can opt for a Geil kiln instead of a site built unit or other
manufacturers unit. They carry AGA certification. The gas people in tow=
will be familiar with this certification (like gas stoves and dryers) and=

it may help.

So.... all the time I have for now. Hope some of those thoughts are of
help from an old longhaired kiln designer / installer / consultant. Best=

of luck with the potential property.




John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA

603-654-2752 (s)
800-900-1110 (s)

" Earth, Water, and Fire Noborigama Woodfiring Workshop August 17-26,