Oxygen Clean Tank

[Dive-aholic]

At the risk...

O2 cleaning is not really necessary every year. Just because you're pulling off the valve and taking a look inside the tank doesn't mean you're exposing hydrocarbons to the inside. If the tank is clean and a proper VIP is done, then there's not point in putting water inside the tank, especially if it's a steel tank. The valve is the bigger issue anyway. But again, if you're doing a proper service and you know where your fills are coming from, then you know there aren't any hydrocarbons in your tank or valve.

There is no law regarding any of this in the US. The standards in place are self imposed. I understand why LDSs insist on full O2 cleaning every year. They don't know where your tank has been. They are the ones taking the risk doing the fills.

I know where all of my tanks get filled. I also do my own PPB at home. My tanks are clean and I'm not going to expose them to water and rust every year if I don't have to.

Okay, let the flames begin...

 

[Crazy Fingers]

I know where all of my tanks get filled. I also do my own PPB at home. My tanks are clean and I'm not going to expose them to water and rust every year if I don't have to.

Okay, let the flames begin...

:no Don't you know the PADI police are going to come get you???

Actually, I know a guy that does PPB at home also. He rents a K-bottle of oxygen for like $13 a month, and gets it filled for like $3. Says he can fill something like a dozen tanks off of it before it needs to be filled again.

His tanks are not oxygen cleaned at all. He's been doing it for years. To those naysayers who talk about oxygen cleaning, think about how much oil and flammable material is actually inside of that tank -- NOT MUCH since you can breathe it just fine. Certainly not enough to make that tank rupture from "burning" it off, and even then the rupture disk would save your ***. The paranoia of the dive industry is ridiculous. But you know why the rules are in place... $$$

 

[cummings66]

You know a guy who's been lucky for years. O2 does carry higher risks, and in fact the valve is probably a bigger risk than the tank itself. It can be done as you've noted, but it is more risky.

You can fill a dirty tank slow and be fine, fill a clean tank fast and have problems. It's got a lot to do with how you fill. In fact, around here some shops O2 clean tanks as a normal cleaning and if you ask for an O2 cleaning you get a different sticker. They believe themselves that an O2 cleaned tank is better in the long run and they don't charge extra for it in fact.

 

[oxyhacker]

Yeah and we used to have a guy who would weld automobile gas tanks with the gas still in them.

Oxygen is completely unpredictable. You can do a lot of stupid or just marginal things with it and get away with it for years, and then one day something blows, and you can lose an arm, or a shop, or a house, and never know why. So there's hardly a rule of O2 handling that you won't find someone merrily ignoring somewhere, often explaining to anyone who will listen why it must be safe, because they've been doing it for so long. Most of them get away with it much of the time, but not all do, all the time. And when incidents do happen, there is rarely a clear or logical explanation afterwards since the fire destroys all the evidence. One guy can be pumping 100% into dirty tanks for years with nothing bad happening, and another person can pump little 02 into an O2-cleaned tank and have it blow.

Usually afterwards it is easy to prove logically that it would not have happened.

Though I wouldn't put too much faith in your burst disk theory. They are simply not designed to cope with the kind of pressure surge that occurs during a major tank conflagration.

Actually, I know a guy that does PPB at home also. He rents a K-bottle of oxygen for like $13 a month, and gets it filled for like $3. Says he can fill something like a dozen tanks off of it before it needs to be filled again.

His tanks are not oxygen cleaned at all. He's been doing it for years. To those naysayers who talk about oxygen cleaning, think about how much oil and flammable material is actually inside of that tank -- NOT MUCH since you can breathe it just fine. Certainly not enough to make that tank rupture from "burning" it off, and even then the rupture disk would save your ***. The paranoia of the dive industry is ridiculous. But you know why the rules are in place... $$$

 

[OWSI176288]

At the risk...

O2 cleaning is not really necessary every year. Just because you're pulling off the valve and taking a look inside the tank doesn't mean you're exposing hydrocarbons to the inside. If the tank is clean and a proper VIP is done, then there's not point in putting water inside the tank, especially if it's a steel tank. The valve is the bigger issue anyway. But again, if you're doing a proper service and you know where your fills are coming from, then you know there aren't any hydrocarbons in your tank or valve.

There is no law regarding any of this in the US. The standards in place are self imposed. I understand why LDSs insist on full O2 cleaning every year. They don't know where your tank has been. They are the ones taking the risk doing the fills.

I know where all of my tanks get filled. I also do my own PPB at home. My tanks are clean and I'm not going to expose them to water and rust every year if I don't have to.

Okay, let the flames begin...

I think you got it exacly right. What's so magical about O2 cleaning every year. You can get a dirty fill anytime. So O2 clean the tank if or when there's any doubt about the purity of air that went in the tank. be it a week, a month, a year, or five years at the time of last hydro, since the last O2 cleaning.

 

[Crazy Fingers]

Usually afterwards it is easy to prove logically that it would not have happened.

Though I wouldn't put too much faith in your burst disk theory. They are simply not designed to cope with the kind of pressure surge that occurs during a major tank conflagration.

Let's be clear: it's a tank full of AIR and some tiny amounts of oil, corroded metal, etc. It's not a cylinder full of acetylene or something. It isn't full of mineral oil or kerosene or coated in cosmoline. I just believe that there simply isn't enough stuff to burn in that tank to cause a "major conflagration."

I want to see a documented instance of a SCUBA cylinder (which was always filled with a BREATHING GAS, not some filthy pressure vessel that used to have oil in it or something) being filled via PPB with O2 that catastrophically exploded due to conflagration. Surely if it is so dangerous someone can provide this information.

Show me REAL evidence and I will shut my mouth about the O2 issue forever.

 

[cummings66]

Remember, it's not only the initial oil or whatever that burns, that's what starts it going and the tank itself can then catch from there, or what it's setting on etc. It takes only the blink of an eye for the AL to catch and within the time it takes you to say oh shi? it's over and you're left with a mess.

The main issue is to treat O2 with the respect it deserves, not ignore it and pretend it can't happen.

My brother in law is a fireman, now he won't tell me of cases where scuba tanks caught fire, but he has told me of the tanks for the people who need supplemental O2 burning. In fact I work for a furniture electronics store and I once had opportunity to measure a house for carpet and work on a TV because the O2 tank they had caught fire and burned up part of the lazyboy chair and carpet it was setting on. He told me it was the second time this happened to them, insurance paid for it by the way.

So even though it's not scuba I know things happen you might think can't happen.

http://www.luxfercylinders.com/support/faq/aluminumoxygen.shtml

All I'm saying is that a person needs to treat O2 with respect, handle it like you were taught. If it bites you it might take a chunk out of you, but you don't know if it's going to do so. I know a person who had welded for most of his life, one day doing what he always did his O2 tank blew and left him scarred for life. His regulator had caused it, he had I think he said oil in the gage or something like that.

Personally since I weld I tried to see if I could start a fire, I took some steel wool and soaked it in oil, took my torch and blew pure O2 on it. Nothing happened. I've also thrown away rags soaked with linseed oil with no problems, I know a person who did that and ended up with major fire damage. Who knows why I got lucky and they didn't.

I'm smarter now, I don't tempt fate because I know now that it can happen. I know you want proof of a Scuba cylinder doing this, but ask any competent fireman about O2 fed fires and what happens and how fast it happens. Just be careful and know that it can happen, just as explosions filling things from a gas can will happen.

That did happen to me. I cringe when I see people do what I did because they've done it all their life without incident. For me I did too, then I had the explosion happen and it changed my respect for gas. The people half a block away told me it sounded like a bomb went off. You know how I did it? I poured gas from my gas can into my cold lawnmower. A plastic gas can did it. Same deal as O2 in scuba cylinders, people do it for decades with no problems, but the fact is it can happen if everything conspires against you and you have no idea it's going on at the time.

I'm lucky, all it did was to burn my hair off and give me mostly second degree burns with a few third degree burns. I fully respect fire and things that can cause it. I wish you did too.

 

[do it easy]

I want to see a documented instance of a SCUBA cylinder (which was always filled with a BREATHING GAS, not some filthy pressure vessel that used to have oil in it or something) being filled via PPB with O2 that catastrophically exploded due to conflagration. Surely if it is so dangerous someone can provide this information.

http://www.scubaboard.com/showthread.php?t=143346 The link to the pictures doesn't work anymore, but just imagine a burnt out garage with charred scuba stuff strewn about the lawn.

I also recall some anecdote about an AL40 that fell over while being filled that killed the operator. I believe this happened in Florida. Maybe some one closer has better details.

 

[dsteding]

Let's be clear: it's a tank full of AIR and some tiny amounts of oil, corroded metal, etc. It's not a cylinder full of acetylene or something. It isn't full of mineral oil or kerosene or coated in cosmoline. I just believe that there simply isn't enough stuff to burn in that tank to cause a "major conflagration."

I want to see a documented instance of a SCUBA cylinder (which was always filled with a BREATHING GAS, not some filthy pressure vessel that used to have oil in it or something) being filled via PPB with O2 that catastrophically exploded due to conflagration. Surely if it is so dangerous someone can provide this information.

Show me REAL evidence and I will shut my mouth about the O2 issue forever.

Let's be clear, you are literally arguing with the guy that wrote the book on the subject . . . off the top of my head, there was that incident a while back in Florida where a guy was boosting O2 in a rented garaged and the fire gutted the place. Granted, he was boosting, but at the same time it does demonstrate that the risk is real.

[EDIT] Tony beat me to it.

[EDIT again, pics here: http://spiralbound.net/wp-gallery2.php?g2_itemId=2309 ]

 

[dsteding]

Personally since I weld I tried to see if I could start a fire, I took some steel wool and soaked it in oil, took my torch and blew pure O2 on it. Nothing happened. I've also thrown away rags soaked with linseed oil with no problems, I know a person who did that and ended up with major fire damage. Who knows why I got lucky and they didn't.

The way a scuba cylinder will combust is if you have hydrocarbons, O2, and then adiabatic heating due to a sharp rise in pressure, the last thing can be tricky, I bet it could be slamming O2 into a tank too fast, or maybe even O2 turning a corner quickly in a valve . . . get the three points of the triangle fire together, and boom goes the dynamite.