Thread: Petrol fumes in old 44 gal. drum

Originally Posted by morrisman

Hi

You would be better off finding drums that contained oil, rather than a explosive fluid like petrol. Castrol used to supply oil in those drums , particularly for diesel truck engines . I've used grinders to cut the tops from those oil drums , no problem at all . Maybe if you try a bulk oil depot somewhere near where you live . Mike

Wow Morrisman, are you sure that's safe?

My understanding was that oil vapours can ignite, just like petrol.

It's for this reason they recommend you don't weld on air compressor tanks as they contain oil vapour from the compressor.

I may be off target on this, but no way I'd try that one. Sounds a bit risky to me.

Rob

That's because they have depleted the oxygen in the car, once depleted they would be breathing straight CO2. You can pump any number of non toxic gasses into a vehicle and live, as long as oxygen is present, but as soon as we use up the oxygen, we die... We can breathe a number of gasses, as long as oxygen is present, for example: scuba divers use a mixture of oxygen (about 20-30%) and nitrogen on deep dives; however, if they were to remove the oxygen from the mix, they would be asphixiated. As a matter of fact, nitrogen has been espoused as a more humane gas for capital punishment: We can breathe it without tasting or smelling it, we simply go to sleep, painlessly.

Originally Posted by tongleh

, for example: scuba divers use a mixture of oxygen (about 20-30%) and nitrogen on deep dives.

The atmosphere is normally 80% nitrogen so that comes as no surprise

Originally Posted by nearnexus

Wow Morrisman, are you sure that's safe?

My understanding was that oil vapours can ignite, just like petrol.

It's for this reason they recommend you don't weld on air compressor tanks as they contain oil vapour from the compressor.

I may be off target on this, but no way I'd try that one. Sounds a bit risky to me.

Rob

Not explosive like petrol, I cut the tops out of oil drums with any oxy torch. Worse that happens is you get a face full of smoke. Go on any farm and you'll see the same.

Only reason why they advise against welding air compressor tanks is because they are a pressure vessel.
Generally of differing thickness caused by rust. And to put it bluntly most people don't have the skill or design knowledge to make safe repairs to pressure vessels.

Garry

The lethality of CO is actually a little more devious than lack of oxygen:
the heamoglobin in our blood (the red colouring of the red blood cells) bind with CO in preference to O2. As a result of that, we can die from Carbon monoxide poisoning in the presence of plenty of oxygen.... sadly.
Joe

Originally Posted by tongleh

, for example: scuba divers use a mixture of oxygen (about 20-30%) and nitrogen on deep dives;

helium??

I should qualify my statement about needing oxygen: We do, but we also need nitrogen, argon and a few others that collectively, make up Air. We need air. Helium is necessary apparently for really deep dives, it staves of nitrogen narcosis. CO is toxic, CO2 is not; however if either is present to the exclusion of air, not good. Mind you have you ever been in a car with exhaust gasses leaking inside: Very hard to take, stinging eyes, coughing hard to breathe, don't know how anyone could do it that way.

I guess this is all a little academic now as Ratty has done the deed and put a big hole in his 44 .

So just a couple of comments and you need to bear in mind I have difficulty counting. Petrol is volatile as we all know and the ignition point is less than ambient air temperature. Consequently any spark produced when there is sufficient oxygen around will cause combustion. If that combustion is out in the open the effect will be relatively mild, but within the confines of container, which will be the 44 in this instance, it becomes a bomb.

The fumes can be trapped in the drum for a long time, years even, primarily caught in the seams of the drum. I was told to rinse a drum prior to cutting six times. That's quite a lot of water. A cold chisel can then be used to cut off the top. Without rinsing, any ferous to ferous contact will potentially produce a spark. Another tool to use is an old leaf spring from a car sharpened for about 50mm at one end. This can be hammered around the drum and the natural curve of the spring will assist. It's probably a little quicker than the chisel because of it's size, but fundamentally does the same job.

Oil residue is unlikely to explode as the ignition point is too high. It will burn and it will smoke and is more like diesel fuel in that regard. This would only be if you oxy cut the top or perhaps if you used an angle grinder. A cold chisel or similar would not be enough to cause ignition. However I would still rinse the drum.

Carbon monoxide (CO) and carbon dioxide (CO2) are very different gases. CO2 like Nitrogen (N2) are inert gases and not poisonous. However we need oxygen to live so that gas must be present in sufficient quantities. CO however will kill even if oxygen is present.

Lastly, (this would be my second point) after having rinsed the drum or container sufficiently the biggest danger is cutting yourself, which I have to say I always manage to do.

Regards
Paul

Oil drum will not ignite. Flash point is approx 180 deg as opposed to petrol which has a flash point of approx -42 deg.

Definition of flash point: Minimum temperature at which a substance will ignite with the application of an ignition source, but will not continue to burn.

Reason the substance will not continue to burn is because the vapour production is not at a high enough rate to sustain combustion. Usually a few degrees higher and you will reach the Fire point: The minimum temperature at which a substance will ignite with the application of an ignition source AND continue to burn.

CO has an affinity with your bodys haemoglobin which is about 100 times stonger than that of O2. Apparently Hydrogen Cyanide is even worse. My understanding of deep sea diving and using a He mix is so that the He (inert gas) replaces the N2 (inert gas) in the gas mix so as to avoid nitrogen narcosis at depth. N2 is not needed by our bodies in the respiration process. We breathe in approx 21% O2, 78% N2 and 1% oth gases. Our exhaled breath contains approx 16% O2, 5% CO2, 78% N2 and the 1% others. Tyhe only gas ratios that change are the O2 and CO2. We don't use any of the other stuff!

*Atmospheres with O2 concentrations greater than 23% are considered O2 enriched.
*Atmospheres with O2 concentrations less than 17% are considered O2 deficient.

*Aust and other int. industry standards.

Sorry to bore you all ####less. It's a slow night at work!

Simon

Hey bts, great answer! That one sounds the safest and for the neat freaks out there . . . a nice clean cut edge too!

To Ratbag, great to hear you're still around to report your results Before everone else races out with their cold chisels, (minor detail?) did you have the drum filled with water as you chiselled?

Originally Posted by Bushmiller

Carbon monoxide (CO) and carbon dioxide (CO2) are very different gases. CO2 like Nitrogen (N2) are inert gases and not poisonous. However we need oxygen to live so that gas must be present in sufficient quantities. CO however will kill even if oxygen is present.

Just a correction
CO2 is poisonous
a quick google returned
The LC50 (Lethal Concentration which kills 50% of the exposed animals in 1 hour) is 4% for rats and 10% for humans.
but my memory is that the lethal level is 15%, regardless of how much oxygen is in the air -- in coal mines CO2 poisioning was at one time known as "choke damp"

Where would we be without google. That one's solved; now, what about the meaning of life, I think we should be able to sort this one out quick smart, surely it can't be as complex as this. Drums - what about drums!

Although I have never had the need to do it,I have always understood that the container should be filled with water before cutting open or repairing via brazing or welding.
As for working on an oil drum, it could also have contained petrol even if some oil was still present.
Russell

Originally Posted by rusty steel

Although I have never had the need to do it,I have always understood that the container should be filled with water before cutting open or repairing via brazing or welding.
As for working on an oil drum, it could also have contained petrol even if some oil was still present.
Russell

I still wouldn't regard oil vapours as non explosive.

Here's a good example:

Oil vapors caused blast that killed 2 workers

Other things that don't even have vapour can blow up too - like flour dust. How many flour mills have blown up - plenty.

So I would always rather be safe than sorry. Water in the drum/tank would always be number one priority with me when cutting/welding.

Too many people get killed being careless with this stuff.

Rob