Julie Milazzo on thu 7 mar 02
OH MY GOD!DON"T EVEN GET ME STARTED ON PRESSURE
COOKERS! Just kidding! Actually, I think my paranoia
was borrowed from past Clayart archives. I've never
used the stuff, and I think my biggest real worry
should be whether some idiot decides to use the tank
for target practice. The kiln will be outside
anyway... Jules
--- Ditmar wrote:
> ...Less fiber in your diet.
>
> More seriously,............. I don't see why there
> is so much paranoia about propane all the time.
> In all of Hawaii there IS no such animal as natural
> gas. Restaurants, hotels, homes and business all use
> propane. ( Obviously some use electricity ) I can't
> recall ever hearing of any catastrophes and homes
> blowing up.
> Sure it may be heavier than air and pool, but only
> if there's a leak. Natural gas is just as dangerous
> if you've got a leak in a closed environment, like a
> home , studio or whatever.
>
> If gas lines are competently installed, and the
> system maintained, any fuel gas is safe !!
> Get over it !! It's almost as bad as people and
> pressure cookers ! Jeez !
>
> Ditmar
>
>
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Ditmar on thu 7 mar 02
...Less fiber in your diet.
More seriously,............. I don't see why there is so much paranoia =
about propane all the time.
In all of Hawaii there IS no such animal as natural gas. Restaurants, =
hotels, homes and business all use propane. ( Obviously some use =
electricity ) I can't recall ever hearing of any catastrophes and homes =
blowing up.=20
Sure it may be heavier than air and pool, but only if there's a leak. =
Natural gas is just as dangerous if you've got a leak in a closed =
environment, like a home , studio or whatever.
If gas lines are competently installed, and the system maintained, any =
fuel gas is safe !!
Get over it !! It's almost as bad as people and pressure cookers ! =
Jeez !
Ditmar
Alan D. Scott on fri 8 mar 02
> The gas that was the source of
> the pretty blue flame that hugged
> the floor was natural gas. Why did
> the gas hug the floor if it is
> "lighter" than air?
Well, one possible explanation is the "gas" the gas company piped you.
While it is usually methane, they do keep stockpiles of propane handy to
send down the pipes if their supply of "natural" gas is interrupted or if
the demand exceeds their supply. If the "gas" company sent you some gas
that was a mixture of methane and propane, it could have been dense enough
to settle.
Alan Scott (retired from the fire service)
j.a.velez on fri 8 mar 02
Julie, Craig et al:
Graig said:
"Julie, according to my source of info for all such matters, my wife Ruth
Kravetz...chemistry teacher extraordinaire, I have
been informed that Propane (C3H8....can't do subscripts sorry) has a molar
mass that is indeed lighter than air. Natural Gas (CH4....with a small
amount of other stuff) has a molar mass that is greater than air."
Craig, I am afraid you got this backwards. Methane has a weight density (at
1 atm. and 70F) of 0.042 lb/cf, while Propane has a density of 0.116 lb/cf.
By comparison air's density is 0.075 lb/cf. In other words, Propane
Specific Gravity is about 1.5, meaning that is about one and one half times
heavier than air, while methane has a Specific Gravity of 0.5, meaning is
about 1/2 lighter than air. A release of Natural Gas into the atmosphere
will disperse a lot faster than a release of Propane. Operators in a
chemical manufacturing plant will say that a Propane release will tend to
"hug the ground".
Julie, if you are building a kiln and you can select location as well as
fuel, I would surely build it outside (not surrounded by a building) and use
Natural Gas. An accidental release of a gaseous fuel into an enclosed space
can be extremely dangerous, specially if you have sources of ignition as is
the case of hot surfaces around a kiln. Many industrial boilers are in fact
built inside buildings for weather considerations, but many safety features
are built into the design to avoid a vapor cloud inside the building.
I hope this helps,
Jose A. Velez
Craig Clark on fri 8 mar 02
Jose, that sounds as right to me as what I was told last night. Guess
I'll just have to take you on your word, ask the boss what's up with this,
and break out the chemistry text that's sitting on the top shelf above my
right shoulder.
I do have one question though. A little over a year ago we had a fire in
the kitchen. This took place a little after midnight. I had been dozing on
the couch while watching a movie, awakened and decided to get a piece of
pizza that I'd left in the over earlier that evening (luckly.)
I went into the kitchen, smelled something a little strange (mercaptons
though I didn't relize it at the time because I was half asleep) opened the
oven door, saw a spark about foot or so above the floor infont of the oven,
and a pretty blue flame spread out across the floor. I sort of just stood
there admiring the beauty of the flame before I came to my senses, grabbed
the fire extinguisher and put out the fire which was also burning under the
sink where a number of clearners were kept. The gas that was the source of
the pretty blue flame that hugged the floor was natural gas.Why did the gas
hug the floor if it is "lighter" than air?
Confused on this one
Craig Dunn CLark
619 East 11 1/2 st
Houston, Texas 77008
(713)861-2083
mudman@hal-pc.org
----- Original Message -----
From: "j.a.velez"
To:
Sent: Friday, March 08, 2002 12:52 AM
Subject: Need help with problem gas
> Julie, Craig et al:
>
>
> Graig said:
>
> "Julie, according to my source of info for all such matters, my wife Ruth
> Kravetz...chemistry teacher extraordinaire, I have
> been informed that Propane (C3H8....can't do subscripts sorry) has a molar
> mass that is indeed lighter than air. Natural Gas (CH4....with a small
> amount of other stuff) has a molar mass that is greater than air."
>
>
> Craig, I am afraid you got this backwards. Methane has a weight density
(at
> 1 atm. and 70F) of 0.042 lb/cf, while Propane has a density of 0.116
lb/cf.
> By comparison air's density is 0.075 lb/cf. In other words, Propane
> Specific Gravity is about 1.5, meaning that is about one and one half
times
> heavier than air, while methane has a Specific Gravity of 0.5, meaning is
> about 1/2 lighter than air. A release of Natural Gas into the atmosphere
> will disperse a lot faster than a release of Propane. Operators in a
> chemical manufacturing plant will say that a Propane release will tend to
> "hug the ground".
>
> Julie, if you are building a kiln and you can select location as well as
> fuel, I would surely build it outside (not surrounded by a building) and
use
> Natural Gas. An accidental release of a gaseous fuel into an enclosed
space
> can be extremely dangerous, specially if you have sources of ignition as
is
> the case of hot surfaces around a kiln. Many industrial boilers are in
fact
> built inside buildings for weather considerations, but many safety
features
> are built into the design to avoid a vapor cloud inside the building.
>
> I hope this helps,
>
> Jose A. Velez
>
>
____________________________________________________________________________
__
> 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.
j.a.velez on fri 8 mar 02
Craig:
>The gas that was the source of
> the pretty blue flame that hugged the floor was natural gas.Why did the
gas
> hug the floor if it is "lighter" than air?
To reconstruct a fire scenario is sort of difficult without knowing all the
details, but Natural Gas (Methane) is in fact lighter than air. If you have
a leak/release Natural Gas without ignition (vapor cloud) of it will rise
in the air and disperse. Problem is when the fire occurs you might be
burning all sort of things in addition to the fuel gas. In your case, I
suspect by the time you noticed this was not a natural gas only fire. You
were burning pizza, oven debris, oven seal, maybe wood, plastic containers
and chemicals from under the sink cabinet, etc. So some of the products of
that combustion, or just heating process might be heavy gases or even
liquids.
Now Craig, the most scary scenario for a gaseous fuel accident is when they
leak, are not ignited immediately and then a source of ignition hits a high
concentration of the flammable material. If it occurs in an enclosed space
you will have an explosion. So the advantage of Methane over Propane is
that if there is a leak into an open area, Methane will rise and disperse
faster reducing the opportunity for ignition.
You were lucky you noticed in time and took the correct action. About a
month ago there was an article on the local paper where apparently a
gentlemen placed a plastic container in an oven. The plastic melted and
released gases, when he open the oven door apparently with the additional
oxygen a ball of fire engulfed him. He died as consequence of the burns.
I am not sure I could explain this to your satisfaction, but tried anyway.
Regards, Jose A. Velez
Julie Milazzo on fri 8 mar 02
Not only have you all helped me feel better about
getting propane rather than natural gas, but you've
also inadvertently helped me out with another problem:
because this property is my house, gallery and studio,
I wanted to make the whole acre non smoking. I don't
want to smell it, and I don't want to have to pick up
nasty butts that are strewn all over my lawn and
garden. However, I also didn't want to piss off any
smokers that would otherwise be positive contributers
to this place. Now, it's a safety issue! Woohoo! I can
rationalize this rule in a much better way than,
"Well, it's my f#@%^&g property, and I don't want it!"
Again, thanks everyone!
--- "j.a.velez" wrote:
> Craig:
>
> >The gas that was the source of
> > the pretty blue flame that hugged the floor was
> natural gas.Why did the
> gas
> > hug the floor if it is "lighter" than air?
>
> To reconstruct a fire scenario is sort of difficult
> without knowing all the
> details, but Natural Gas (Methane) is in fact
> lighter than air. If you have
> a leak/release Natural Gas without ignition (vapor
> cloud) of it will rise
> in the air and disperse. Problem is when the fire
> occurs you might be
> burning all sort of things in addition to the fuel
> gas. In your case, I
> suspect by the time you noticed this was not a
> natural gas only fire. You
> were burning pizza, oven debris, oven seal, maybe
> wood, plastic containers
> and chemicals from under the sink cabinet, etc. So
> some of the products of
> that combustion, or just heating process might be
> heavy gases or even
> liquids.
>
> Now Craig, the most scary scenario for a gaseous
> fuel accident is when they
> leak, are not ignited immediately and then a source
> of ignition hits a high
> concentration of the flammable material. If it
> occurs in an enclosed space
> you will have an explosion. So the advantage of
> Methane over Propane is
> that if there is a leak into an open area, Methane
> will rise and disperse
> faster reducing the opportunity for ignition.
>
> You were lucky you noticed in time and took the
> correct action. About a
> month ago there was an article on the local paper
> where apparently a
> gentlemen placed a plastic container in an oven.
> The plastic melted and
> released gases, when he open the oven door
> apparently with the additional
> oxygen a ball of fire engulfed him. He died as
> consequence of the burns.
>
> I am not sure I could explain this to your
> satisfaction, but tried anyway.
>
> Regards, Jose A. Velez
>
>
______________________________________________________________________________
> 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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Craig Clark on sat 9 mar 02
Alan, that sounds reasonable. Thanx for the explanation.
Craig Dunn CLark
619 East 11 1/2 st
Houston, Texas 77008
(713)861-2083
mudman@hal-pc.org
----- Original Message -----
From: "Alan D. Scott"
To:
Sent: Friday, March 08, 2002 9:52 PM
Subject: Re: Need help with problem gas
> > The gas that was the source of
> > the pretty blue flame that hugged
> > the floor was natural gas. Why did
> > the gas hug the floor if it is
> > "lighter" than air?
>
> Well, one possible explanation is the "gas" the gas company piped you.
> While it is usually methane, they do keep stockpiles of propane handy to
> send down the pipes if their supply of "natural" gas is interrupted or if
> the demand exceeds their supply. If the "gas" company sent you some gas
> that was a mixture of methane and propane, it could have been dense enough
> to settle.
>
> Alan Scott (retired from the fire service)
>
>
____________________________________________________________________________
__
> 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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