Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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  #1   Report Post  
davefr
 
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Default How would you cut the top off a 500 gallon underground gas tank?

I buried a 500 gallon gas tank in the late '70's for farm use. I used
it for about 10 years and then pumped it dry.

Complete removal is impractical since a small shed is built on top of
it and I don't want to demolish the shed.

I'd really like to cut the top off and fill it with rock or dirt so
it's decommisioned once and for all.

I checked with the state DEQ office and they told me 500 gallon tanks
are unregulated. My only obligation is to report a spill but this
tank never leaked since I quit using it very early in it's life.

I'm not too fond of the idea of using a cutting torch. Even though
it's totally dry there could still be fumes and I don't want to get
dead. For the same reason, I really don't want to use an angle
grinder.

I'm thinking sawsall or pneumatic chisel.

Anyone know how underground tanks are decomisioned? I'd like to
remove a 5' X 2' portion of it's top.

Is there a safe way to make 100% sure the tank is vented such as
injecting an inert gas that's heavier then gasoline fumes to drive
them out?

Other suggestions?




  #2   Report Post  
SHIVER ME TIMBERS
 
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davefr wrote:

Is there a safe way to make 100% sure the tank is vented such as
injecting an inert gas that's heavier then gasoline fumes to drive
them out?

Other suggestions?


Could you fill it with water, and pump it out after.
  #3   Report Post  
Gary Owens
 
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You don't really need to cut the top off the tank to fill it with sand.
There should be 4 2" fittings on the top, remove all the pipes and fill it
through the fittings. Use clean dry sand and it won't take that long. I
don't know where your located, but if the tank is a homeowner tank, no one
really keeps track of them. Just fill it with sand, and if your worried
about some one using it, cap it with concrete.
gary


"davefr" wrote in message
...
I buried a 500 gallon gas tank in the late '70's for farm use. I used
it for about 10 years and then pumped it dry.

Complete removal is impractical since a small shed is built on top of
it and I don't want to demolish the shed.

I'd really like to cut the top off and fill it with rock or dirt so
it's decommisioned once and for all.

I checked with the state DEQ office and they told me 500 gallon tanks
are unregulated. My only obligation is to report a spill but this
tank never leaked since I quit using it very early in it's life.

I'm not too fond of the idea of using a cutting torch. Even though
it's totally dry there could still be fumes and I don't want to get
dead. For the same reason, I really don't want to use an angle
grinder.

I'm thinking sawsall or pneumatic chisel.

Anyone know how underground tanks are decomisioned? I'd like to
remove a 5' X 2' portion of it's top.

Is there a safe way to make 100% sure the tank is vented such as
injecting an inert gas that's heavier then gasoline fumes to drive
them out?

Other suggestions?






  #4   Report Post  
Tony
 
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I abandoned a 4000 gallon gas tank after the 1998 EPA regs came into
effect. Filled with water (from the nearby hydrant) until water came out the
vent pipe. Then sawcut and jackhammered throught the slab to get to the
tank, Sawzalled a 2x2 square, then pumped out the water (your supposed to
have a vac truck properly dispose of the contaminated water), then filled
with concrete slurry (3 truck loads).

You need to fill the tank with slurry to prevent explosive vapors from
forming in the future, or you need to wash the tank and make sure there are
zero detectable hydrocarbons, there are special meters that do such a thing,
my way is easier.

Tony
"davefr" wrote in message
...
I buried a 500 gallon gas tank in the late '70's for farm use. I used
it for about 10 years and then pumped it dry.

Complete removal is impractical since a small shed is built on top of
it and I don't want to demolish the shed.

I'd really like to cut the top off and fill it with rock or dirt so
it's decommisioned once and for all.

I checked with the state DEQ office and they told me 500 gallon tanks
are unregulated. My only obligation is to report a spill but this
tank never leaked since I quit using it very early in it's life.

I'm not too fond of the idea of using a cutting torch. Even though
it's totally dry there could still be fumes and I don't want to get
dead. For the same reason, I really don't want to use an angle
grinder.

I'm thinking sawsall or pneumatic chisel.

Anyone know how underground tanks are decomisioned? I'd like to
remove a 5' X 2' portion of it's top.

Is there a safe way to make 100% sure the tank is vented such as
injecting an inert gas that's heavier then gasoline fumes to drive
them out?

Other suggestions?






  #5   Report Post  
Not Me
 
Posts: n/a
Default

"davefr"

| I buried a 500 gallon gas tank in the late '70's for farm use. I used
| it for about 10 years and then pumped it dry.
|
| Complete removal is impractical since a small shed is built on top of
| it and I don't want to demolish the shed.
|
| I'd really like to cut the top off and fill it with rock or dirt so
| it's decommissioned once and for all.
|
| I checked with the state DEQ office and they told me 500 gallon tanks
| are unregulated. My only obligation is to report a spill but this
| tank never leaked since I quit using it very early in it's life.
|
| I'm not too fond of the idea of using a cutting torch. Even though
| it's totally dry there could still be fumes and I don't want to get
| dead. For the same reason, I really don't want to use an angle
| grinder.
|
| I'm thinking sawsall or pneumatic chisel.
|
| Anyone know how underground tanks are decommissioned? I'd like to
| remove a 5' X 2' portion of it's top.
|
| Is there a safe way to make 100% sure the tank is vented such as
| injecting an inert gas that's heavier then gasoline fumes to drive
| them out?
|
| Other suggestions?

Fill it with sand. No cutting needed and if you ever have to reactivate the
tank (assuming it has not rusted trough) just vacuum the sand out of the
tank. Don't laugh they've been doing this with decommissioned service
stations for years.

As to making the tank 'gas free' use live steam. Again the oil industry has
been doing things this was for over 50 years that I know of personally and
likely longer.

A sawsall or pneumatic chisel can still generated sufficient heat/sparks to
cause problems.

As to using an inert gas to drive out the fuel vapor, it's only necessary to
drive out the air (O2 actually)




  #6   Report Post  
davefr
 
Posts: n/a
Default

Filling it with sand sounds like a good option. Do you just make a
big funnel and shovel it in? I know my tank has 2 large fittings at
each end but I'll have to check if there are additional plugs in the
middle section.

I'm guessing 2.5 - 3 cubic yards of sand should be enough..

I'm not too keen on the idea of flushing with water. If there's dried
up leaded gasoline on the inner walls, I'd just soon it remain
undisturbed.


On Sun, 13 Mar 2005 00:34:13 GMT, "Gary Owens"
wrote:

You don't really need to cut the top off the tank to fill it with sand.
There should be 4 2" fittings on the top, remove all the pipes and fill it
through the fittings. Use clean dry sand and it won't take that long. I
don't know where your located, but if the tank is a homeowner tank, no one
really keeps track of them. Just fill it with sand, and if your worried
about some one using it, cap it with concrete.
gary


"davefr" wrote in message
.. .
I buried a 500 gallon gas tank in the late '70's for farm use. I used
it for about 10 years and then pumped it dry.

Complete removal is impractical since a small shed is built on top of
it and I don't want to demolish the shed.

I'd really like to cut the top off and fill it with rock or dirt so
it's decommisioned once and for all.

I checked with the state DEQ office and they told me 500 gallon tanks
are unregulated. My only obligation is to report a spill but this
tank never leaked since I quit using it very early in it's life.

I'm not too fond of the idea of using a cutting torch. Even though
it's totally dry there could still be fumes and I don't want to get
dead. For the same reason, I really don't want to use an angle
grinder.

I'm thinking sawsall or pneumatic chisel.

Anyone know how underground tanks are decomisioned? I'd like to
remove a 5' X 2' portion of it's top.

Is there a safe way to make 100% sure the tank is vented such as
injecting an inert gas that's heavier then gasoline fumes to drive
them out?

Other suggestions?






  #7   Report Post  
Dean Hoffman
 
Posts: n/a
Default

davefr wrote:
I buried a 500 gallon gas tank in the late '70's for farm use. I used
it for about 10 years and then pumped it dry.

Complete removal is impractical since a small shed is built on top of
it and I don't want to demolish the shed.

I'd really like to cut the top off and fill it with rock or dirt so
it's decommisioned once and for all.

I checked with the state DEQ office and they told me 500 gallon tanks
are unregulated. My only obligation is to report a spill but this
tank never leaked since I quit using it very early in it's life.

I'm not too fond of the idea of using a cutting torch. Even though
it's totally dry there could still be fumes and I don't want to get
dead. For the same reason, I really don't want to use an angle
grinder.

I'm thinking sawsall or pneumatic chisel.

Anyone know how underground tanks are decomisioned? I'd like to
remove a 5' X 2' portion of it's top.

Is there a safe way to make 100% sure the tank is vented such as
injecting an inert gas that's heavier then gasoline fumes to drive
them out?

Other suggestions?

One trick I've seen is to run a hose from an exhaust pipe of
a running
engine. The exhaust gases will drive out the gas fumes.


Dean

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  #8   Report Post  
Not Me
 
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Default


"davefr" wrote in message
...
| Filling it with sand sounds like a good option. Do you just make a
| big funnel and shovel it in? I know my tank has 2 large fittings at
| each end but I'll have to check if there are additional plugs in the
| middle section.
|
| I'm guessing 2.5 - 3 cubic yards of sand should be enough..
|
| I'm not too keen on the idea of flushing with water. If there's dried
| up leaded gasoline on the inner walls, I'd just soon it remain
| undisturbed.
|

Use a small air compressor and a DIY sand blasting rig. Only caution don't
sniff the exhaust from the tank g Might have to top it off in a day or so
after the sand settles a bit.


  #9   Report Post  
Not Me
 
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Default


"Ignoramus14003"

| Even easier (and safer) would be to put down a hose from a compressor,
| and let it pump air for a day, while at the same time trying to smell
| the air coming out. I would think that if there is no perceptible
| smell, including from an air sample from the bottom, there should not
| be much risk of an explosion. But, better safe than sorry.

I would not want to bet my life on that option. Especially since the simple
act of cutting can release more fumes.


  #10   Report Post  
Ivan Vegvary
 
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Be careful. In the tank removal industry they use dry ice to displace the
volatiles within the tank. We usually break about 20 lbs. of dry ice into
pieces small enough to place down the 2" fill pipe. After sniffing no
hydrocarbons with a tester (usually 10-24 hours) we would excavate and
either remove the tank, or wash in place and then remove.

Be very careful with all tanks. There have been many instances of purged
tanks, at scrap yards, exploding and killing people months and years after
purging. The product is imbedded on the walls of the tank and evaporates
for a long, long time. e.g. tanks that are properly cleaned and safe can
become dangerous by letting them sit for a long time.

If you fill the tank, a weak concrete slurry is typical. I don't remember
from my engineering days what the porosity is for sand, but, rest assured
that uniformly graded sand is probably 20% voids and can hold volatile
hydrocarbons making them dangerous.

Ivan Vegvary
"davefr" wrote in message
...
I buried a 500 gallon gas tank in the late '70's for farm use. I used
it for about 10 years and then pumped it dry.

Complete removal is impractical since a small shed is built on top of
it and I don't want to demolish the shed.

I'd really like to cut the top off and fill it with rock or dirt so
it's decommisioned once and for all.

I checked with the state DEQ office and they told me 500 gallon tanks
are unregulated. My only obligation is to report a spill but this
tank never leaked since I quit using it very early in it's life.

I'm not too fond of the idea of using a cutting torch. Even though
it's totally dry there could still be fumes and I don't want to get
dead. For the same reason, I really don't want to use an angle
grinder.

I'm thinking sawsall or pneumatic chisel.

Anyone know how underground tanks are decomisioned? I'd like to
remove a 5' X 2' portion of it's top.

Is there a safe way to make 100% sure the tank is vented such as
injecting an inert gas that's heavier then gasoline fumes to drive
them out?

Other suggestions?








  #11   Report Post  
Ann
 
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Default

On Sun, 13 Mar 2005 04:41:47 +0000, Ivan Vegvary wrote: ...
Be very careful with all tanks. There have been many instances of
purged tanks, at scrap yards, exploding and killing people months and
years after purging. The product is imbedded on the walls of the tank
and evaporates for a long, long time. e.g. tanks that are properly
cleaned and safe can become dangerous by letting them sit for a long
time.

...

Years ago, a man brought some sort or tank or drum that had held gasoline
in to the shop where my father worked. Don't recall if he wanted it
welded or cut, but my father refused to do it. Then, to demonstrate that
he'd gotten the tank "clean", the man lit a (wood) match and stuck his
hand in the tank. He hadn't.

Also, what about the glop that's left when gas deteriorates/evaporates; is
it flammible?
  #12   Report Post  
Lucky Strike
 
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One trick I've seen is to run a hose from an exhaust pipe of
a running
engine. The exhaust gases will drive out the gas fumes.


Even easier (and safer) would be to put down a hose from a compressor,
and let it pump air for a day, while at the same time trying to smell
the air coming out. I would think that if there is no perceptible
smell, including from an air sample from the bottom, there should not
be much risk of an explosion. But, better safe than sorry.

i


The exhaust idea sounds a lot better than the compressed air.

Haven't you ever seen the fuel delivery guy drop his cigarette but down the
hole at the gas station? No air down there to support combustion...


  #13   Report Post  
Offbreed
 
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Ignoramus14003 wrote:

Even easier (and safer) would be to put down a hose from a compressor,


A compressor does not pump enough cubage. They are intended for pressure.

and let it pump air for a day, while at the same time trying to smell
the air coming out. I would think that if there is no perceptible
smell, including from an air sample from the bottom, there should not
be much risk of an explosion. But, better safe than sorry.


I get a numb nose and cannot smell anything after about the third whiff.
(No, not huffing. Gas mixed with 2-stroke smells different from straight
gas, and it's easy to get the cans mixed up after they've been sitting
for a few weeks.)
  #14   Report Post  
davefr
 
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I could also tape a flexible dryer hose to the outlet tube of a leaf
blower and vent it out for awhile. However that would could also
create a perfect blast furnace.

I really like the dry ice idea. Do supermarkets sell dry ice these
days?? Is there any common source for getting dry ice??



On 13 Mar 2005 03:17:46 GMT, Ignoramus14003
wrote:

On Sat, 12 Mar 2005 20:16:31 -0600, Dean Hoffman wrote:
davefr wrote:
I buried a 500 gallon gas tank in the late '70's for farm use. I used
it for about 10 years and then pumped it dry.

Complete removal is impractical since a small shed is built on top of
it and I don't want to demolish the shed.

I'd really like to cut the top off and fill it with rock or dirt so
it's decommisioned once and for all.

I checked with the state DEQ office and they told me 500 gallon tanks
are unregulated. My only obligation is to report a spill but this
tank never leaked since I quit using it very early in it's life.

I'm not too fond of the idea of using a cutting torch. Even though
it's totally dry there could still be fumes and I don't want to get
dead. For the same reason, I really don't want to use an angle
grinder.

I'm thinking sawsall or pneumatic chisel.

Anyone know how underground tanks are decomisioned? I'd like to
remove a 5' X 2' portion of it's top.

Is there a safe way to make 100% sure the tank is vented such as
injecting an inert gas that's heavier then gasoline fumes to drive
them out?

Other suggestions?

One trick I've seen is to run a hose from an exhaust pipe of
a running
engine. The exhaust gases will drive out the gas fumes.


Even easier (and safer) would be to put down a hose from a compressor,
and let it pump air for a day, while at the same time trying to smell
the air coming out. I would think that if there is no perceptible
smell, including from an air sample from the bottom, there should not
be much risk of an explosion. But, better safe than sorry.

i


  #15   Report Post  
RoyJ
 
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I read the whole string of other comments and just have to make my own:
sometimes it's just better to do something right. Move the shed, get a
backhoe to pull it out and haul it off. Tank is probably 4' in diameter,
5' long, perhaps 400 pounds. Then it is done and gone, no further worries.

Next door neighbors had a 1000 gallon fuel oil tank buried underneath
thier 2 car garage floor. Even that took only about 4 hours to remove.

davefr wrote:
I buried a 500 gallon gas tank in the late '70's for farm use. I used
it for about 10 years and then pumped it dry.

Complete removal is impractical since a small shed is built on top of
it and I don't want to demolish the shed.

I'd really like to cut the top off and fill it with rock or dirt so
it's decommisioned once and for all.

I checked with the state DEQ office and they told me 500 gallon tanks
are unregulated. My only obligation is to report a spill but this
tank never leaked since I quit using it very early in it's life.

I'm not too fond of the idea of using a cutting torch. Even though
it's totally dry there could still be fumes and I don't want to get
dead. For the same reason, I really don't want to use an angle
grinder.

I'm thinking sawsall or pneumatic chisel.

Anyone know how underground tanks are decomisioned? I'd like to
remove a 5' X 2' portion of it's top.

Is there a safe way to make 100% sure the tank is vented such as
injecting an inert gas that's heavier then gasoline fumes to drive
them out?

Other suggestions?






  #16   Report Post  
Ned Simmons
 
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In article , ignoramus3883
@NOSPAM.3883.invalid says...
On Sun, 13 Mar 2005 06:27:20 -0800, Offbreed wrote:
Ignoramus14003 wrote:

Even easier (and safer) would be to put down a hose from a compressor,


A compressor does not pump enough cubage. They are intended for pressure.


Mine pumps about 11 cfm at about 120 PSI, continuously. It is about
100 CFM uncompressed. I would say that it is quite a bit. After a day
of pumping, it would pump 144,000 cubic feet of uncompressed air. For
a 500 gallon tank, which is 70 cubic feet, the day of pumping is 2,000
times the volume of the tank.


Assuming it's rated honestly, your compressor pumps 11 SCFM of air at
atmospheric pressure and temperature when it's delivering 120 psi at the
outlet - closer to 200 air changes.

I'd also reconsider drawing a potentially explosive mixture into the
compressor where it will be compressed and heated. If you really wanted
to do this (I don't think it addresses the OP's concerns, and I'm not
recommending it), drawing the fumes through a gasoline engine might be a
safer approach.

Ned Simmons
  #17   Report Post  
 
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I would go with the concrete idea, but you may be able to do it on the
cheap. Contact concrete suppliers in your area, and ask them if you can
have the extra cement mix after the trucks do their pour. There is
almost always a surplus of cement in the mix truck after a
foundation/footing pour, and they have a limited amount of time to get
it out, and it can be a problem of where to put it (it is often buried
at the jobsite, to the chagrin of a homeowner who later tries to dig
out the spot). If your location is not too remote, they will gladly
take it to you. Just be sure you are there when they come and have the
job prepared, otherwise they will dump it in a pile on your property,
rather than have it set up in the truck mixer. It will take awhile, be
patient. They will also want to rinse the mixer with a hose, no problem
for this type of pour since concrete quality is not that important in
your application. Best wishes for your project.-Jitney

  #18   Report Post  
Peter Fairbrother
 
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Ivan Vegvary wrote:

If you fill the tank, a weak concrete slurry is typical. I don't remember
from my engineering days what the porosity is for sand, but, rest assured
that uniformly graded sand is probably 20% voids and can hold volatile
hydrocarbons making them dangerous.


If the tank is completely filled with sand it should be safe.


Gas fumes aren't dangerous, it's gas-air mixtures that are. You need a large
continuous volume too (large meaning a pint or so) for the flame front to
propagate and grow in size, speed and power. Start with a sphere and it's
really dangerous, spread the same volume out in pipes and it's much less so
- the pipes absorb some of the energy, and they also prevent the reaction
from going to completion in the small volumes closest to the walls, the gas
there can't get hot enough.


The tiny holes in bulk sand are sufficiently small and dispersed and
surrounded by sand so that even if one ignited* the sand would quickly damp
out the flame and it would not spread.

* this would actually be impossible, with the cold sand forming the walls of
the cavity so close



Hard to fill a tank with sand so that there are no large voids though, and
hard to be sure. Same with filling it with concrete, will there still be any
large voids? Because they _will_ fill with fumes, even through concrete, if
there are any fumes to be had (and if there aren't any, then it doesn't
matter anyway).



--
Peter Fairbrother

  #19   Report Post  
Bruce L. Bergman
 
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On Sun, 13 Mar 2005 07:59:39 -0500, "Lucky Strike"
wrote:


The exhaust idea sounds a lot better than the compressed air.

Haven't you ever seen the fuel delivery guy drop his cigarette but down the
hole at the gas station? No air down there to support combustion...


You hope.

In theory, or under precisely controlled conditions, yes you can
extinguish a burning match in liquid gasoline. In practice...?

I sure don't want to be there the day someone tries that cigarette
trick and the vapor recovery system is screwed up, to where it has
sucked in an above-LEL level of atmospheric oxygen in the tank.

They'll hear that sucker go BOOM! in the next state, and they'll be
picking up pieces of the delivery driver with tweezers.

"No brains, No headaches."

-- Bruce --
--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545
Spamtrapped address: Remove the python and the invalid, and use a net.
  #20   Report Post  
SHIVER ME TIMBERS
 
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Bruce L. Bergman wrote:

They'll hear that sucker go BOOM! in the next state, and they'll be
picking up pieces of the delivery driver with tweezers.


Years ago when I drove taxi, another driver fuelled up his propane
powered cab one winters day.

The overflow valve had frozen shut so the driver bent over
with a bic lighter and decided to thaw it out.

It thawed.

No - It didn't go kaboom, but he lost all the hair on his face and
suffered some interesting burn patterns in the process.

Yah I know it's a little off the subject but this thread has brought
back some interesting recollections of my days of driving propane
powered taxis.


  #21   Report Post  
Offbreed
 
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davefr wrote:
I could also tape a flexible dryer hose to the outlet tube of a leaf
blower and vent it out for awhile. However that would could also
create a perfect blast furnace.


I'm not comfortable with the idea of betting airing out will do the job
well enough. Too many tanks started stinking after they set a while, no
matter how well I aired them out, or washed them out. (Unless I used
really hot water.)

I really like the dry ice idea. Do supermarkets sell dry ice these
days?? Is there any common source for getting dry ice??


That can be tricky to find. Gell ice is air shippable, dry ice is not.
Some places quit carrying it.
  #22   Report Post  
Not Me
 
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"Lucky Strike" wrote in message
...
|
| One trick I've seen is to run a hose from an exhaust pipe
of
| a running
| engine. The exhaust gases will drive out the gas fumes.
|
| Even easier (and safer) would be to put down a hose from a compressor,
| and let it pump air for a day, while at the same time trying to smell
| the air coming out. I would think that if there is no perceptible
| smell, including from an air sample from the bottom, there should not
| be much risk of an explosion. But, better safe than sorry.
|
| i
|
| The exhaust idea sounds a lot better than the compressed air.
|
| Haven't you ever seen the fuel delivery guy drop his cigarette but down
the
| hole at the gas station? No air down there to support combustion...

And you sat around, watched and did nothing?


  #23   Report Post  
Not Me
 
Posts: n/a
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"Ignoramus3883" wrote in message
...
| On Sun, 13 Mar 2005 06:27:20 -0800, Offbreed
wrote:
| Ignoramus14003 wrote:
|
| Even easier (and safer) would be to put down a hose from a compressor,
|
| A compressor does not pump enough cubage. They are intended for
pressure.
|
| Mine pumps about 11 cfm at about 120 PSI, continuously. It is about
| 100 CFM uncompressed. I would say that it is quite a bit. After a day
| of pumping, it would pump 144,000 cubic feet of uncompressed air. For
| a 500 gallon tank, which is 70 cubic feet, the day of pumping is 2,000
| times the volume of the tank.

Unless you have a sure way to verify that the tank is gas free you have
better odds in Vegas. At least there you lose only your money.


  #24   Report Post  
Doctor John
 
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I guess I should pipe up here since this is an area I have some experience
in. When we remove underground tanks for disposal, we throw a pile of dry
ice in prior to doing anything. The idea is that the CO2 released will
gradually fill the tank with a gas which does not support combustion. I
have never had to cut into an UST, the dry ice is added just for digging it
out safely. Cutting into one sounds like it could evoke the Darwin Effect.
Good luck.

John

"Offbreed" wrote in message
...
Ignoramus14003 wrote:

Even easier (and safer) would be to put down a hose from a compressor,


A compressor does not pump enough cubage. They are intended for pressure.

and let it pump air for a day, while at the same time trying to smell
the air coming out. I would think that if there is no perceptible
smell, including from an air sample from the bottom, there should not
be much risk of an explosion. But, better safe than sorry.


I get a numb nose and cannot smell anything after about the third whiff.
(No, not huffing. Gas mixed with 2-stroke smells different from straight
gas, and it's easy to get the cans mixed up after they've been sitting
for a few weeks.)



  #25   Report Post  
Dan Murphy
 
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davefr wrote in news:r84731pp2go7hd9vte21kr93r0q36llb2l@
4ax.com:

I'm guessing 2.5 - 3 cubic yards of sand should be enough..


Pretty good guess. 500 gallons = 2.48 cubic yards.

Dan


  #26   Report Post  
davefr
 
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Thanks for all the replies. The job is done.

I used the dry ice method to purge the fumes. Then I used my cordless
Sawzall to decapitate a 2' X 6' section of the top. (it actually cut
easier then I thought). The inner walls and bottom looked clean and
in good condition so I just filled it with dirt and compacted it as
best I could.

Cost:
$15 for 10# of dry ice
$8 for a 5 pack of bi metal Sawzall blades.
About $5 in tractor diesel getting fill dirt
$28 Total (not including a couple gin and tonics for my sore back)



On Sat, 12 Mar 2005 15:52:07 -0800, davefr wrote:

I buried a 500 gallon gas tank in the late '70's for farm use. I used
it for about 10 years and then pumped it dry.

Complete removal is impractical since a small shed is built on top of
it and I don't want to demolish the shed.

I'd really like to cut the top off and fill it with rock or dirt so
it's decommisioned once and for all.

I checked with the state DEQ office and they told me 500 gallon tanks
are unregulated. My only obligation is to report a spill but this
tank never leaked since I quit using it very early in it's life.

I'm not too fond of the idea of using a cutting torch. Even though
it's totally dry there could still be fumes and I don't want to get
dead. For the same reason, I really don't want to use an angle
grinder.

I'm thinking sawsall or pneumatic chisel.

Anyone know how underground tanks are decomisioned? I'd like to
remove a 5' X 2' portion of it's top.

Is there a safe way to make 100% sure the tank is vented such as
injecting an inert gas that's heavier then gasoline fumes to drive
them out?

Other suggestions?




  #27   Report Post  
gfulton
 
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"SHIVER ME TIMBERS" wrote in message
...
Bruce L. Bergman wrote:


They'll hear that sucker go BOOM! in the next state, and they'll be
picking up pieces of the delivery driver with tweezers.


Years ago when I drove taxi, another driver fuelled up his propane
powered cab one winters day.

The overflow valve had frozen shut so the driver bent over
with a bic lighter and decided to thaw it out.

It thawed.

No - It didn't go kaboom, but he lost all the hair on his face and
suffered some interesting burn patterns in the process.

Yah I know it's a little off the subject but this thread has brought
back some interesting recollections of my days of driving propane
powered taxis.




He lit




A match




To check




His tank.






That's why





They called him






Skinless Frank.





BURMA SHAVE




(Seen from the backseat of a '56 Pontiac somewhere in Southern Illinois,
about 1958).


Garrett Fulton




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  #28   Report Post  
Pat Ford
 
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fill it with concrete?
Pat


"SHIVER ME TIMBERS" wrote in message
...
davefr wrote:


Is there a safe way to make 100% sure the tank is vented such as
injecting an inert gas that's heavier then gasoline fumes to drive
them out?

Other suggestions?


Could you fill it with water, and pump it out after.



  #29   Report Post  
bigegg
 
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Peter Fairbrother wrote:
The tiny holes in bulk sand are sufficiently small and dispersed and
surrounded by sand so that even if one ignited* the sand would
quickly damp out the flame and it would not spread.

* this would actually be impossible, with the cold sand forming the
walls of the cavity so close



Hard to fill a tank with sand so that there are no large voids
though, and hard to be sure. Same with filling it with concrete, will
there still be any large voids? Because they _will_ fill with fumes,
even through concrete, if there are any fumes to be had (and if there
aren't any, then it doesn't matter anyway).


I would use sand, and a concrete poker to make sure there's no voids.

Also - anyone familiar with a "desert burner" (1)
Basically, it's a bucket full of sand and petrol (gasoline), making sure
there are no puddles on the surface. Drop a match on and it burns
(controllably) for a good five or six hours.

Don't know if this will work in an enclosed tank.

--
BigEgg



  #30   Report Post  
Gerald Miller
 
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On Mon, 14 Mar 2005 09:16:33 -0500, "Pat Ford"
wrote:

fill it with concrete?
Pat

Why not just dig the D*** thing out and be done with it. If you try to
hide it, it will come back and haunt you!
Gerry :-)}
London, Canada


  #31   Report Post  
tom
 
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The way you weld a gas line that is less say 24" is to put dry ice in
the pipe. you block it off on one end and put about 40 pounds of dry
ice in a bucket of water lit gas off and weld away.

Larry


On Mon, 14 Mar 2005 19:56:57 -0000, "bigegg"
wrote:

Peter Fairbrother wrote:
The tiny holes in bulk sand are sufficiently small and dispersed and
surrounded by sand so that even if one ignited* the sand would
quickly damp out the flame and it would not spread.

* this would actually be impossible, with the cold sand forming the
walls of the cavity so close



Hard to fill a tank with sand so that there are no large voids
though, and hard to be sure. Same with filling it with concrete, will
there still be any large voids? Because they _will_ fill with fumes,
even through concrete, if there are any fumes to be had (and if there
aren't any, then it doesn't matter anyway).


I would use sand, and a concrete poker to make sure there's no voids.

Also - anyone familiar with a "desert burner" (1)
Basically, it's a bucket full of sand and petrol (gasoline), making sure
there are no puddles on the surface. Drop a match on and it burns
(controllably) for a good five or six hours.

Don't know if this will work in an enclosed tank.


  #32   Report Post  
Grant Erwin
 
Posts: n/a
Default


Anyone know how underground tanks are decomisioned?


They are filled with sand and plugged. - GWE
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