Oxygen compatibility, materials and explosions

[tech_diver]

I spent years working for a scuba manufacturer that also sold air station and cascade components. We had a commercial dive customer call and say that four of our line valves (brand new) all failed. Failures were very rare for this part so four in a row raised eyebrows. We got them back and all the seats were scorched, melted. The customer insisted they were part of an air system and never saw oxygen. Eventually, we found that when receiving large racks of O2 bottles, one of their people would check the pressure of the incoming O2 racks by simply connecting them to the air system to read the gauge instead of dragging O2 gear from across the boat. He opened the valve and the O2 hit the next closed valve downstream at the speed of sound, burned the seat, went down the line to hit and burn the next valve seats down the line. The seats were an O2 compatible material but not cleaned for O2 service.


People think oxygen service means it's O2 clean and O2 compatible but oxygen service also requires O2 compatible design. That is that there are no sharp constrictions, bends or sudden compressions to anger the gas.

 

[Wookie]

Yes I pump oxygen through the compressor at 80% and no I won’t have an explosion, oxygen is not explosive and the conditions to cause an explosion are not present

I have this friend, used to live in Key West. Bought a brand new Bauer 8 cfm compressor. Decided to pump 70% through it, I said “steve, that compressor is going to burn”. This is the same guy who regularly dives to 200+ on air with the Helldivers and “cleans up” on 70%. He only gets bent now and again, he keeps a bottle of 100% to deco at 30 feet if he does get bent. It’s important to know that he is certified as neither a gas blender, a deco diver, nor a deep diver. But I digress. As Steve was filling his something with 70% he heard a boom, a whistle, and a boom. First boom was the relief lifting on his sintered filter. Whistle was the flames coming out of the relief valve, and second boom was the relief valve shrapnel blowing the back of his pickup truck off. He learned his lesson, though. He pumps no more than 50% now.

Mac, that compressor is going to burn.

 

[Rred]

IIRC a we search on "scuba tank explosion" will get you a list of incidents including those attributed to improper oxygen fills. There was one in Florida maybe 6? years ago, there have been several with injuries and fatalities.

 

[Celt]

I have this friend, used to live in Key West. Bought a brand new Bauer 8 cfm compressor. Decided to pump 70% through it, I said “steve, that compressor is going to burn”. This is the same guy who regularly dives to 200+ on air with the Helldivers and “cleans up” on 70%. He only gets bent now and again, he keeps a bottle of 100% to deco at 30 feet if he does get bent. It’s important to know that he is certified as neither a gas blender, a deco diver, nor a deep diver. But I digress. As Steve was filling his something with 70% he heard a boom, a whistle, and a boom. First boom was the relief lifting on his sintered filter. Whistle was the flames coming out of the relief valve, and second boom was the relief valve shrapnel blowing the back of his pickup truck off. He learned his lesson, though. He pumps no more than 50% now.

Mac, that compressor is going to burn.

Don’t know what he did wrong but I’m guessing he pumped to hard and to fast and there was some other flammable source it’s like anything you have to take some care.

 

[Akimbo]

Fires and explosions are a funny thing. They do observe the laws of physics and are fully predictable -- when you can measure all the variables in real time. Pressure and O2 percentage is easy. The amount of fuel and the temperature at the microsecond that combustion occurs is more difficult. Don't confuse getting away with risky procedures with reliably safe.

You may find some of the information in this thread useful: O-rings for Divers, Post #3

 

[rddvet]

Don’t know what he did wrong but I’m guessing he pumped to hard and to fast and there was some other flammable source it’s like anything you have to take some care.

No offense, but you're taking the idea that oxygen itself isn't flammable and taking it to far. You've got, oil, oxygen, and heat. That equals fire.

Keep doing doing what you want, but it is not a wise idea. Apparently you feel as though you have some secret that the scuba industry and military just don't understand.

There's three reasons you feel the way you do:
1) you're a genius and know more than anyone else
2) you're an idiot who thinks he knows more than anyone else
3) you've got some big balls and just don't give a ****.

Either way, just make sure you don't have any friends, family, or customers around when you're pumping 80%. If you want to blow yourself up, that's perfectly OK. Just don't take anybody else down with you.

 

[Scared Silly]

2) you're an idiot who thinks he knows more than anyone else

i.e, a potential Dunning-Kruger Effect case study

 

[TrimixToo]

Yes I pump oxygen through the compressor at 80% and no I won’t have an explosion, oxygen is not explosive and the conditions to cause an explosion are not present

Those who have posted that you should not do this are dead right. If you continue doing this long enough, which could be the very next time, you could be lethally wrong. You're free to blow yourself up, if you wish, but I'd rather you didn't and I'd much rather you didn't bring anyone with you when it happens.

In a non-diving forum I once tried to convince one particularly stubborn poster that high-speed O2 transfills via whips of dubious construction and cleanliness from T-bottles to small welding tanks were a bad idea. I failed. I have no idea whether he still does it. I am very happy he does not live next door though.

See also:

Professionalism/Diane Vaughan and the normalization of deviance - Wikibooks, open books for an open world

 

[Celt]

Those who have posted that you should not do this are dead right. If you continue doing this long enough, which could be the very next time, you could be lethally wrong. You're free to blow yourself up, if you wish, but I'd rather you didn't and I'd much rather you didn't bring anyone with you when it happens.

In a non-diving forum I once tried to convince one particularly stubborn poster that high-speed O2 transfills via whips of dubious construction and cleanliness from T-bottles to small welding tanks were a bad idea. I failed. I have no idea whether he still does it. I am very happy he does not live next door though.

See also:

Professionalism/Diane Vaughan and the normalization of deviance - Wikibooks, open books for an open world

But that’s the beauty of sending it through the compressor, unlike decanting, it’s not going at high speed , you simply trickle oxygen with a needle valve from the j bottle Into the air intake,no sudden rise in heat and it mixes in the compressor, what could be simpler.

 

[Celt]

No offense, but you're taking the idea that oxygen itself isn't flammable and taking it to far. You've got, oil, oxygen, and heat. That equals fire.

Keep doing doing what you want, but it is not a wise idea. Apparently you feel as though you have some secret that the scuba industry and military just don't understand.

There's three reasons you feel the way you do:
1) you're a genius and know more than anyone else
2) you're an idiot who thinks he knows more than anyone else
3) you've got some big balls and just don't give a ****.

Either way, just make sure you don't have any friends, family, or customers around when you're pumping 80%. If you want to blow yourself up, that's perfectly OK. Just don't take anybody else down with you.

Actually there’s a very simple reason for sending it through the compressor, when the pressure in the j bottle drops to low to decant you can use all of the remaining gas and I don’t have the budget of the military or industry, Alao oil can’t ignite til it reaches a flash point and compressors are designed to run at less than a third of that.