Reg Wearley on thu 19 oct 00
Hi Dave, et el-
I am a little confused over some of the comments
about propane tanks. Even though I worked with
propane for a number of years I am not familiar
with "vents" on a propane tank. Propane sits in
the tank like water until a valve is opened and
it is allowed to piped to a burner somewhere.
When there is no gas being drawn the tank has
a pressure of around 100 psi, give or take a few
psi depending on the outside temprature (this
will also be the temprature of the propane liquid
in the tank-until you open the valve. At that
instant the temp. of the liquid will drop. The
greater the draw, the greater the drop in temp.)
What I am getting at here has to do with how you
'vent' a tank which has approx. 100 psi in it?
Also, someone commented about "the propane should
be nice and warm" when it gets to the kiln. I
hope that person wasn't under the impression that
that was liquid propane getting to the kiln!
The very best advice will come from your propane
provider. They will explain how the whole system
works and what safety precautions you must take.
After-all, they have a vested interest in how
your gas system works. If you are not satisfied
with what one serviceman tells you, definately
get a second opinion. Let me know if you are
still not comfortable. --Reg Wearley
Big Arm, MT
--- Dave and Janet Evans
wrote:
> Regarding propane tanks,
>
> These tanks need to be able to vent. Some
> effort should be taken to keep them free of too
> much snow, and they should not be buried.
> Differential heating between the piping and
> snow can form a conduit-like tube around the
> pipe. Vented propane could then inch up the
> line, pooling under the house until it finds an
> ignition source. A house or to a year goes up
> this way a year in the Sierras. Just take a
> little time, especially after a thick
> blanketing, wade out to the tank, and dig out
> the vent. Some units do have a vent stack and
> this should be kept clear.
>
> Enjoy your firing,
>
> John Evans in San Diego
>
>
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Reg Wearley on fri 20 oct 00
Hi Feri-
I guess I am of the opinion that the propane
tank and the regulator are seperate units. Yes,
the REGULATOR must be vented and that is a lot
different than the tank being 'vented'. Also,
the regulator vent is to the outside atmosphere
and its main function is to allow the diaphram
in the regulator to move freely. And you are
correct in that if the diaphram does get a leak
the gas will escape through the vent. But, this
leaking gas will dissipate into the air as the
regulator is probably located very near the tank.
The pipe would not be involved with the escaping
gas.
Also, since propane is propane regardless where
you find it I have to question your psi numbers,
Feri. Are you using "pounds per square inch" or
some other units? Most of our propane appliances
operate at 11 inches of water column pressure.
To obtain this the 100psi tank pressure is
reduced
to 10psi at the tank with a first stage regulator
(usually painted red) and this gas is piped to
the house or shop where a second stage regulator
reduces the 10psi to the 11 inches of water
column
which is about 1/2 psi. In some systems a SINGLE
stage regulator is used to do the same thing with
just one regulator. Also, many kilns are designed
to operate at much higher pressures and they use
a more customized regulator setup. Let me know
what differences you have with what I describe
here. -Reg Wearley
--- ferenc jakab wrote:
> Reg,
> I don't know about American systems, but I
> imagine they are similar to ours
> here in Australia. The vent is on the
> regulator, it allows gas to escape in
> the event that the regulator diaphram develops
> a hole. Our propane develops
> a tank pressure of 250 psi and the regulator
> lowers that to 130 psi. We
> don't have buried systems here (or none that I
> know of), but I can imagine
> the vented gas following the path of least
> resistance along the pipe line.
> Feri.
>
>
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ferenc jakab on fri 20 oct 00
Reg,
I don't know about American systems, but I imagine they are similar to ours
here in Australia. The vent is on the regulator, it allows gas to escape in
the event that the regulator diaphram develops a hole. Our propane develops
a tank pressure of 250 psi and the regulator lowers that to 130 psi. We
don't have buried systems here (or none that I know of), but I can imagine
the vented gas following the path of least resistance along the pipe line.
Feri.
ARTISTINSC@AOL.COM on fri 20 oct 00
In my area of South Carolina you had not better bury any fuel tank without
doing a lot of homework first and calling the proper authorities as buried
tanks were all required to be regulated a couple years back due to lack of
documentation and numerous unknown ones that either leaked or were found by
unsuspecting land purchasers. Many gasoline stations went out of business
then and it also was pointed out to me that many propane refueers
could/would not fill a tank unless it were either installed by them or dug up
and inspected first. Also do not mix propane and other farm type " bottled"
gas types as their properties are different.( I AM NOT REFERRING TO GASOLINE,
KEROSENE NOR OIL HERE EITHER).
M.
ferenc jakab on sun 22 oct 00
----- Original Message -----
From: "Reg Wearley"
To:
Sent: Saturday, 21 October 2000 2:52 pm
Subject: Re: Propane question-tank vent?
> Hi Feri-
> I guess I am of the opinion that the propane
> tank and the regulator are seperate units. Yes,
> the REGULATOR must be vented and that is a lot
> different than the tank being 'vented'.
I agree here.
Also,
> the regulator vent is to the outside atmosphere
Usually, I have an adjustable second regulator in the kiln shed which vents
into the shed.
> and its main function is to allow the diaphram
> in the regulator to move freely. And you are
> correct in that if the diaphram does get a leak
> the gas will escape through the vent. But, this
> leaking gas will dissipate into the air as the
> regulator is probably located very near the tank.
> The pipe would not be involved with the escaping
> gas.
The pipe is attached to the regulator and if both are buried the vented gas
has to follow the line of least resistance which may be the path of the
buried line. I'm guessing as I have never seen a buried system.
> Also, since propane is propane regardless where
> you find it I have to question your psi numbers,
> Feri. Are you using "pounds per square inch" or
> some other units?
Even though we measure pressure in kpa here I was using good old fashioned
pounds per square inch. My small kiln has to full pressure lpg burners which
can operate at 130 psi. I adjust this and to be honest I have never used
more than 6 psi in a firing.
My big kiln was converted from natural gas and is regulated to 5 kpa or
about .8 psi. the house supply taken off the same tanks is regulated to 5
kpa also. Both regulators are OPSO meaning they have an over pressure cut
out.
I assure you my psi figures are correct as used here in Australia.
Feri.
John Baymore on mon 23 oct 00
Usually, I have an adjustable second regulator in the kiln shed which ven=
ts
into the shed.
So much of any gas installation depends on the local level of codes and
such. I have done kiln installations (urban) where code specified that t=
he
vent on any interior located regulator had to be plumbed via schedule 40
black iron pipe to vent to the exterior of the structure.
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"
Reg Wearley on tue 24 oct 00
Hi John,
I agree that local codes do vary some. For the
most part however, gas system installations
follow the National Fire Safety Code which does
state, as you say, that any regulator placed
inside of a building must be vented outside. Of
course it is the regulator that is vented-not
the propane tank. -Reg Wearley
--- John Baymore wrote:
>
> Usually, I have an adjustable second regulator
> in the kiln shed which vents
> into the shed.
>
>
> So much of any gas installation depends on the
> local level of codes and
> such. I have done kiln installations (urban)
> where code specified that the
> vent on any interior located regulator had to
> be plumbed via schedule 40
> black iron pipe to vent to the exterior of the
> structure.
>
> 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"
>
>
______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or
> change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may
> be reached at melpots@pclink.com.
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