Jon Pettyjohn on wed 9 sep 98
Hi,
We've had 2 explosive events in the last year or so.
Fortunately no one was hurt and there was no damage
to the kiln or pots but I'm getting a little worried
that it might happen again and we won't be so lucky.
The problem is that many people can never remember
which way to turn the valve (we're using globe valves
with round knobs) to make sure it's in the off position
before lighting the first burner.
My assitant who often starts the firings seems to
be a bit dyslexic about which way to close the knob,
clockwise or counter clockwise, and twice he's
inadvertently had more than 1 of our 6 burners on
when going to light the first, resulting in an
explosion. It doesn't help that we always do this at
5:00 AM when we're barely conscious either.
I'm wondering if there's any safer way to do this,
I don't think I've heard of any safety equipment that
deals with this situation. We usually take a walk
around the kiln after pressurizing the manifold line
and check the individual pressure gauges on the burners
but gauges sometimes stick. Only other thing I can think
of is the smell, but in my case for example I've lost
most of my sense of smell from my chronic allergies.
The only real test I know of whether there is any gas
in the kiln before lighting is to stick a flame in the
burner port and see. I usually stand back when doing this,
and sometimes when the burner "pops" I jump.
Anyone know of any device that can detect LPG in the
kiln before lighting, something that doesn't cost a
fortune maybe? Think a canary might do? Is there a way
to take the guess work out of kiln lighting?
Jon Pettyjohn,
Manila,
jon@mozcom.com
John H. Rodgers on thu 10 sep 98
-- [ From: John H. Rodgers * EMC.Ver #2.5.02 ] --
No airplane pilot ever operates his airplane without going over a rigid
written checklist. On small planes and airliners alike, the engines aren't
even started before going over a written checklist.
Take no chances. Familiarity breeds contempt.
Before someone gets killed, write a pre-lighting check list of how things
are to be set before lighting, and demand the list be followed, and if
someone can't remember clockwise from counterclockwise, put arrows on the
handles and describe it in the checklist. Leave nothing to chance.
I knew a bearded someone who "forgot" and lit his burners a little to long
after they were turned on. He looked funny with that red flash burned face
and all that frizzle-fried beard and eyelashes. Took him a while to put his
brick-stack kiln back up too.. Very lucky!!
Follow that checklist!!!!
Life is to short as it is.
John Rodgers
-------- REPLY, Original message follows --------
Date: Wednesday, 09-Sep-98 09:59 AM
From: Jon Pettyjohn \ Internet: (jon@mozcom.com)
To: Multiple recipients of list CLAYART \ Internet: (clayart@lsv.uky.
edu)
Subject: LPG kiln lighting accidents
----------------------------Original message----------------------------
Hi,
We've had 2 explosive events in the last year or so. Fortunately no one was
hurt and there was no damage to the kiln or pots but I'm getting a little
worried that it might happen again and we won't be so lucky.
The problem is that many people can never remember which way to turn the
valve (we're using globe valves with round knobs) to make sure it's in the
off position before lighting the first burner.
My assitant who often starts the firings seems to be a bit dyslexic about
which way to close the knob, clockwise or counter clockwise, and twice he's
inadvertently had more than 1 of our 6 burners on when going to light the
first, resulting in an explosion. It doesn't help that we always do this at
5:00 AM when we're barely conscious either.
I'm wondering if there's any safer way to do this, I don't think I've heard
of any safety equipment that deals with this situation. We usually take a
walk around the kiln after pressurizing the manifold line and check the
individual pressure gauges on the burners but gauges sometimes stick. Only
other thing I can think of is the smell, but in my case for example I've
lost most of my sense of smell from my chronic allergies.
The only real test I know of whether there is any gas in the kiln before
lighting is to stick a flame in the burner port and see. I usually stand
back when doing this, and sometimes when the burner "pops" I jump.
Anyone know of any device that can detect LPG in the kiln before lighting,
something that doesn't cost a fortune maybe? Think a canary might do? Is
there a way to take the guess work out of kiln lighting?
Jon Pettyjohn,
Manila,
jon@mozcom.com
-------- REPLY, End of original message --------
--
John Rodgers
'85 GL Vanagon Driver
Clayartist/Moldmaker
"God created His best work from clay, shall I strive to do less?"jr
Bruce Girrell on thu 10 sep 98
Jon,
I would say that the following paragraph from your post says it all:
> The problem is that many people can never remember
> which way to turn the valve (we're using globe valves
> with round knobs) to make sure it's in the off position
> before lighting the first burner.
>
Putting a canary in the kiln only tells you after the fact that you have
done something wrong (and is a waste of good canaries), rather than
preventing you from doing something wrong to begin with.
I work in the oil field where they have large lines with high pressure
operated by (how can I put this nicely?) the occasional mentally challenged
field hand.
Multiturn valves (those that require multiple rotations of the shaft in
order to open or close, such as gate valves) are very clearly marked with
the words OPEN and/or CLOSE molded into the handle or valve body along with
an arrow indicating the proper direction to turn the handle.
Quarter turn ball valves (the kind I think you mean) have an elongated lever
like handle, not a round one. They are also indelibly marked with OPEN and
an arrow or CLOSE with an arrow. In addition, the handle is mounted so that
when the valve is open, then handle is in line with the flow and when the
valve is closed, the handle is perpendicular to the flow, as if it were
blocking the flow, adding some visual feedback.
Get rid of the round knobs! Indelibly mark [1] the handles in the largest
possible letters with OPEN and/or CLOSE and direction arrow(s). Paint large
pictures on the floor or the wall directly underneath or behind the valve so
that when the valve handle is in the proper position it will line up with
the diagram. Have you ever seen a pegboard in a handyman's shop where each
tool on the board has an outline drawn around it so that it will be obvious
which tool to put where on the board? Do the same thing so that when you
look at the valve and valve handle you will see the outline directly behind.
The outline that lines up visually with the valve should be the one of the
valve in the _closed_ position. Place any drawing of the valve in the open
position adjacent to the closed one.
If you think that two drawings may be confusing, show only the closed
position.
You've been lucky two times so far. Don't count on any more help from above
or you may be going there yourself.
Hopefully, Marc Ward will jump in here and tell you about safety shutoff
devices. These are really the way to go, but even if you use them, you
should still provide visual cues like the ones I suggested above.
Bruce "and hang up a No Smoking sign, too" Girrell
[1] Use metal stamps, an engraver, or perhaps a wire welder to write the
words. Do not assume that paint or laundry marker will last.
Vince Pitelka on thu 10 sep 98
>We've had 2 explosive events in the last year or so.
>Fortunately no one was hurt and there was no damage
>to the kiln or pots but I'm getting a little worried
>that it might happen again and we won't be so lucky.
>The problem is that many people can never remember
>which way to turn the valve (we're using globe valves
>with round knobs) to make sure it's in the off position
>before lighting the first burner.
Jon -
I certainly do not want to seem to make light of a very serious problem, but
I do not see the difficulty here. Except for a few water faucets on kitchen
sinks, all gate and globe valves close in a clockwise direction as you look
down upon the handle, and open in a counter-clockwise direction. Put up
some big signs on the kiln where the valves are located, instructing all
persons lighting the kiln to make sure that all burner valves are turned as
far as they will go in a clockwise direction. And of course, they only need
to be snug. It does no good to overtighten them - it just wears out the
seals. If you simply make clear that there is NO ACCEPTABLE PRACTICE except
to check all valves to make sure that they have been turned off in a
clockwise direction BEFORE LIGHTING THE KILN. Then, open the single valve
for the burner you are lighting, turning in a counter-clockwise direction
just enough to light the kiln.
Regarding safety systems, does this kiln have any at all? Normally, one
lights the pilots first, energizing the baso valves, before lighting the
main burners. This eliminates the situation you describe. Once all the
pilots are lit, the burners may be turned on with no danger.
If your burners are under the kiln, you might consider an ignition ring and
a single pilot light. The pilot is located adjacent to one of the main
burners and the ignition ring. The pilot lit first, and once the baso valve
is energized gas can get through to the ignition ring and the main burners.
The ignition ring is just a long tube burner, capped or crimped on the end,
with a continuous line of small holes drilled along the length of it. It is
bent in a circle or square so that it comes close to all the main burners.
After the pilot is lit, the ignition ring is turned on, and the flame
travels along it from the pilot light, igniting the entire length of the
ignition ring. This continuous row of flames ignite the main burners. The
ignition ring may be turned on low to provide an excellent means of
preheating the kiln. Most potters turn it off after the main burners have
been going for a while.
Good luck -
- Vince
Vince Pitelka - vpitelka@DeKalb.net
Home 615/597-5376, work 615/597-6801, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Grimmer on thu 10 sep 98
John,
Golly, there are few better illustrations of why a safety system is so
important on a gas kiln!
The simplest to use and install is a Baso valve/thermocouple combination.
They work just like the systems on furnaces and water heaters: no gas can
flow to any burner unless that burner's pilot is on and the thermocouple
sends a voltage to the valve. You need one for each burner. It's a good
idea to use real pilot burners, too, not some bic-lighter size deal designed
for a hot water heater. Those blow out too easily and are often incapable of
igniting the main burner. Ward Burner has a good selection and good prices.
Usual disclaimers.
Other types of safety systems involve IR flame sensors and spark
ignition systems. These are expensive, require 120V at the kiln, and work
very quickly in the event of trouble to shut off the gas. Nice to push a
button and have the burner light itself, too. If I recall correctly, you
need this type of system for any burner rated over 200,000 BTu/hr. Baso-type
systems can take as much as a minute to shut off the main gas in the event
of flame-out, and you don't want one burner to fill the kiln with gas while
the other candles away, waiting. . .
One last thing I would recommend is a standard, gas ball valve for each
burner. Parallel, and gas is on; perpendicular, and the gas is off. Easy.
Hope this is of some help. I'm not an expert, but did some reading on the
subject. Please, please install a safety system! The cost is low compared to
the risk!
steve grimmer
marion illinois
----------
>From: Jon Pettyjohn
>To: CLAYART@LSV.UKY.EDU
>Subject: LPG kiln lighting accidents
>Date: Wed, Sep 9, 1998, 8:59 AM
>
>----------------------------Original message----------------------------
>Hi,
>
>We've had 2 explosive events in the last year or so.
>Fortunately no one was hurt and there was no damage
>to the kiln or pots but I'm getting a little worried
>that it might happen again and we won't be so lucky.
>
>The problem is that many people can never remember
>which way to turn the valve (we're using globe valves
>with round knobs) to make sure it's in the off position
>before lighting the first burner.
>
>My assitant who often starts the firings seems to
>be a bit dyslexic about which way to close the knob,
>clockwise or counter clockwise, and twice he's
>inadvertently had more than 1 of our 6 burners on
>when going to light the first, resulting in an
>explosion. It doesn't help that we always do this at
>5:00 AM when we're barely conscious either.
>
>I'm wondering if there's any safer way to do this,
>I don't think I've heard of any safety equipment that
>deals with this situation. We usually take a walk
>around the kiln after pressurizing the manifold line
>and check the individual pressure gauges on the burners
>but gauges sometimes stick. Only other thing I can think
>of is the smell, but in my case for example I've lost
>most of my sense of smell from my chronic allergies.
>
>The only real test I know of whether there is any gas
>in the kiln before lighting is to stick a flame in the
>burner port and see. I usually stand back when doing this,
>and sometimes when the burner "pops" I jump.
>
>Anyone know of any device that can detect LPG in the
>kiln before lighting, something that doesn't cost a
>fortune maybe? Think a canary might do? Is there a way
>to take the guess work out of kiln lighting?
>
>Jon Pettyjohn,
>Manila,
>jon@mozcom.com
Fay & Ralph Loewenthal on thu 10 sep 98
Jon et al, I was taught that one always lights a flame from a
match or lighter before one opens the tap. This makes good
safety sense. I am horrified when I read how many potters
are opening the tap before having a flame ready. Is there
any reason why one should not work this way? Hope this
helps to cut out the explosions. Ralph in PE SA
Dannon Rhudy on fri 11 sep 98
I have to agree here. I never even push the button
to light the pilot light without a flame already there
to ignite the gas at once. This may just be a hangover
from my never-used-gas-for-anything youth. When I
first started firing kilns, they were the first gas appliances
I'd ever used, and I was intimidated by the negative
possibilities. So - the rule at the studio is: make a
long paper torch, light it first, then turn on the gas.
No clickers, no lighters, nothing that permits the
gas to accumulate even a small amount.
That's cause ah'm a-scairt of explosions.
Dannon Rhudy
----------
> From: Fay & Ralph Loewenthal
> To: CLAYART@LSV.UKY.EDU
> Subject: LPG kiln lighting accidents
> Date: Thursday, September 10, 1998 1:20 PM
>
> ----------------------------Original message----------------------------
> Jon et al, I was taught that one always lights a flame from a
> match or lighter before one opens the tap. This makes good
> safety sense. I am horrified when I read how many potters
> are opening the tap before having a flame ready. Is there
> any reason why one should not work this way? Hope this
> helps to cut out the explosions. Ralph in PE SA
Scott Barnim on fri 11 sep 98
vince, If the valves are confussing to people in the workshop it is not
that much money to replace them with something more obvious. The next step
is to insure that your flame safety equipment is in good order, and if not
REPLACE IT. If your firing without flame safety equipment, you are, well to
be frank, a bit of an idiot. If its a case of getting your match lite after
the gas is on??? then invest ina small propace torch and use this to light
the piolots.
Scott Barnim, 15 Park Street East, Dundas, Ontario.L9H1C9
Barnim@interlynx.net
----------
> From: Vince Pitelka
> To: CLAYART@LSV.UKY.EDU
> Subject: Re: LPG kiln lighting accidents
> Date: Thursday, September 10, 1998 6:16 AM
>
> ----------------------------Original message----------------------------
> >We've had 2 explosive events in the last year or so.
> >Fortunately no one was hurt and there was no damage
> >to the kiln or pots but I'm getting a little worried
> >that it might happen again and we won't be so lucky.
> >The problem is that many people can never remember
> >which way to turn the valve (we're using globe valves
> >with round knobs) to make sure it's in the off position
> >before lighting the first burner.
>
> Jon -
> I certainly do not want to seem to make light of a very serious problem,
but
> I do not see the difficulty here. Except for a few water faucets on
kitchen
> sinks, all gate and globe valves close in a clockwise direction as you
look
> down upon the handle, and open in a counter-clockwise direction. Put up
> some big signs on the kiln where the valves are located, instructing all
> persons lighting the kiln to make sure that all burner valves are turned
as
> far as they will go in a clockwise direction. And of course, they only
need
> to be snug. It does no good to overtighten them - it just wears out the
> seals. If you simply make clear that there is NO ACCEPTABLE PRACTICE
except
> to check all valves to make sure that they have been turned off in a
> clockwise direction BEFORE LIGHTING THE KILN. Then, open the single
valve
> for the burner you are lighting, turning in a counter-clockwise direction
> just enough to light the kiln.
>
> Regarding safety systems, does this kiln have any at all? Normally, one
> lights the pilots first, energizing the baso valves, before lighting the
> main burners. This eliminates the situation you describe. Once all the
> pilots are lit, the burners may be turned on with no danger.
>
> If your burners are under the kiln, you might consider an ignition ring
and
> a single pilot light. The pilot is located adjacent to one of the main
> burners and the ignition ring. The pilot lit first, and once the baso
valve
> is energized gas can get through to the ignition ring and the main
burners.
> The ignition ring is just a long tube burner, capped or crimped on the
end,
> with a continuous line of small holes drilled along the length of it. It
is
> bent in a circle or square so that it comes close to all the main
burners.
> After the pilot is lit, the ignition ring is turned on, and the flame
> travels along it from the pilot light, igniting the entire length of the
> ignition ring. This continuous row of flames ignite the main burners.
The
> ignition ring may be turned on low to provide an excellent means of
> preheating the kiln. Most potters turn it off after the main burners
have
> been going for a while.
> Good luck -
> - Vince
>
> Vince Pitelka - vpitelka@DeKalb.net
> Home 615/597-5376, work 615/597-6801, fax 615/597-6803
> Appalachian Center for Crafts
> Tennessee Technological University
> 1560 Craft Center Drive, Smithville TN 37166
Earl Brunner on fri 11 sep 98
Years ago when I was still a production potter in Utah (or attempting such) ,
there was a trucking firm in a little town south of us that ran produce to
southern California, they were always looking for a load to bring back and we
could get a ton or more of clay from Westwood for really cheap shipping. they
graduated to bringing Mexican pottery up into the area and from that went to
manufacturing their own. They built a big envelope kiln out of fiber and soft
brick, as I remember it was about 100 c.f. They fired on propane. One day
they had someone light the kiln with a rolled newspaper taper, hadn't checked
the valves first. They found the East end of the kiln one block away, up
against the wall of the elementary school. Fortunately they didn't "kiln"
anybody. Pretty well destroyed the kiln.
Earl Brunner
Marc Ward on fri 11 sep 98
Bruce wrote;
<<devices. These are really the way
to go, but even if you use them, you should still provide visual cues like the
ones I suggested above.>>>
Well, I don't know about jumping in...how 'bout peeking in and shuddering?
Bruce is right about getting rid of the globe valves. Quarter-turn ball valves
provide a greater margin of safety. A simple glance will confirm whether they
are off or on. Let's all assume you'll change these valves out before your
next firing. Safety valves such as BASO Valves would provide a further degree
of safety by making it necessary to "prove" a standing pilot light before gas
will flow to the main burner. It sounds like you've been lucky so far, I
wouldn't tempt fate much longer.
Marc Ward
Ward Burner Systems
PO Box 333
Dandridge, TN 37725
USA
423.397.2914 voice
423.397.1253 fax
wardburner@aol.com
Marc Ward on fri 11 sep 98
Hey folks,
I saw one other item that I felt needed a warning. Here it is;
<<<thermocouple
sends a voltage to the valve.>>>>
Not always true. There are some BASO valves, such as the Johnson H19RA high
pressure BASO, that do not have flow interupters. This means that when the
reset button is pushed, gas passes to both the main burner and the pilot. With
these valves you have to make sure your main burner valve is off before you
try to light the pilot. Otherwise you'll light both which can be surprising.
Or, in the worst case, you hold down the reset button thinking only the pilot
is letting a little bit of gas out... you're looking around for a
match...finally find one and then you get a BOOM because the main burner was
also dumping gas into the kiln. Be careful out there...
Marc Ward
Ward Burner Systems
PO Box 333
Dandridge, TN 37725
USA
423.397.2914 voice
423.397.1253 fax
wardburner@aol.com
Jon Pettyjohn on sat 12 sep 98
Hi everyone,
thanks for all the replies and advice about preventing
light up explosions. I will engrave, paint, draw, a clear
directional arrow to avoid this dangerous dyslexic confusion
in the future. Most of the replies favor the lever handle type
globe valve as well for obvious reasons.
Now on the question of safety equipment I must now confess
I don't have any and I am unaware of any potteries here
in South East Asia that use them. I suppose that these
devices seem somewhat expensive to us here, especially with
the sad state of our currencies lately. But as some you pointed
out to me this is a mistaken economy when the risks are weighed
in.
Now begging your indulgence here if this seems a stupid
question, but would a Baso shut off, pilot light, and flame
sensor system prevent the light up accident I described
(when another burner is inadvertently been left on while
lighting up the first burner)?
Can this equipment be operated with battery back-up or
battery power alone?
If so I will try to install it asap. Won't have to kill
the canary.
thanks,
Jon Pettyjohn,
Manila,
jon@mozcom.com
Marc Ward on sun 13 sep 98
Jon asked;
<<<question, but would a Baso shut off, pilot light, and flame
sensor system prevent the light up accident I described
(when another burner is inadvertently been left on while
lighting up the first burner)?
Can this equipment be operated with battery back-up or
battery power alone?>>>>
Almost always..., if you use a BASO valve with "interuption" and each burner
has a BASO valve. In this instance, each burner would have a pilot light of
some sort and that pilot would have to be "proven" to the BASO valve before
you could get gas to the main burner. No need for battery backup, matter of
fact, there's no need for electricity of any sort. The millivolts produced by
the thermocouple and "read" by the BASO, are what runs the system.
Now, why the qualifier at the beginning of the previous paragragh? As I've
gotten older, I've gotten almost 100 percent sure that nothing is 100 percent
sure.
Marc Ward
Ward Burner Systems
PO Box 333
Dandridge, TN 37725
USA
423.397.2914 voice
423.397.1253 fax
wardburner@aol.com
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