Oxygen Explosions

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I'm cringing when I ask this, but here goes anyway...Why won't the oxygen used in my O/A rig burn (by itself), while oxygen in medical applications is explosive?  Is it just a matter of purity?  If so, at what purity (%) does oxygen become explosive?
Reply:oxygen isn't explosive.. it's a "fuel enhancer" (oxidizer).. if you catch on fire, your cloths are the fuel... oxygen enriched clothing (say, from blowin yourself down with a torch) will burn a gazillion times quicker than normal "atmospheric" clothing.. and quick too.. i mean from ordinary sparks from a grinder or cigerette (hence no smoking in a hospital)..if you're not livin on the edge, you're takin up too much room..
Reply:I know what you’re driving at, but technically you’re wrong. Oxygen is needed to make things burn. The more oxygen the faster and hotter the burn. In chemistry, oxygen is classified as an oxidizing agent and any elements that work the same way are oxidizing agents. Chlorine is an oxidizing agent.
Reply:There's really no difference between the medical O2 and welding O2. In both, most places will vac the bottles prior to filling, and then fill from the same tap. Medical O2 usually has paperwork attached however so it can be tracked by lot. Technically its a drug according to the feds. Both are usually 99.95+% pure.I usually use Medical O2 both for welding and for mixing dive gas. There's also Aviator grade O2. That is required to be tested and have a super low moisture content so it won't freeze in high altitude aircraft systems.There's nothing explosive about O2. O2 by itself is relatively harmless. However almost all materials will burn in the presence of 100% O2, especially at higher pressures. What is generally thought of as an "explosion" is just the extremely rapid combustion of materials in the presence of O2. I had an O2 booster pump go bad on me. It vaporized 20 some inches of 1/4" SS high pressure tubing in the blink of an eye when something failed and the temp reached critical temp. My arm which was next to the line at the time recieved 3rd degree burns, from the fireball, but as soon as the  SS "fuel" was consumed, the fire went out.Frequently people just don't treat O2 with respect. When I was burned, I talked to one of the nurses in the burn ward. She commented that most of their O2 "burns" resulted from people on medical O2 smoking. The O2 would pool and then an ember would fall in the O2 rich area and POOF, instant fire. Liquid O2 is even worse, as many things will combust instantly in contact with it.The biggest thing with O2, is to NEVER use any oils or non O2 compatible materials with anything that can come in contact with 100% O2..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Originally Posted by transitI know what you’re driving at, but technically you’re wrong. Oxygen is needed to make things burn. The more oxygen the faster and hotter the burn. In chemistry, oxygen is classified as an oxidizing agent and any elements that work the same way are oxidizing agents. Chlorine is an oxidizing agent.
Reply:Originally Posted by ibanezed4yrswho me?.. no i aint.. i never said you didn't need oxygen to burn.. i actually said you did need it to burn.. and may i add, since i put "oxidizer" in parenthasis, you would figure i know that there are others out there...........................
Reply:lol.. ooops.. my bad.. if you're not livin on the edge, you're takin up too much room..
Reply:Fun, easy way to show how oxygen works as an accelerant for a burn: Take 1 cheap cigar, and light it. Note how slow it burns. Take another cigar, pump oxygen through it at low pressure, 2-3 psi for 10 seconds to saturate the cigar. Light it, and watch it burn, much much faster.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:Please don't flame me if this turns out to be stupid. I always wondered about spontanious combustion and I always wanted to do this experiment but didn't because not sure of the end result. I wanted to take a shop rag with oil on it and use an unlit torch to blow O2 in the rag until it combusts. Now this feat (of possible stupidity) would occur in the middle of a gravel area. Would this be safe or STUPID? Now this has been on my mind for at least ten years but I don't do possibly stupid things on purpose. This thread just reminded me of it."Where's Stick man????????" - 7A749"SHHHHHH!! I sent him over to snag that MIC-4 while tbone wasn't looking!" - duaneb55"I have bought a few of Tbone's things unlike Stick-Man who helps himself" - TozziWelding"Stick-man"
Reply:Originally Posted by Stick-manPlease don't flame me if this turns out to be stupid. I always wondered about spontanious combustion and I always wanted to do this experiment but didn't because not sure of the end result. I wanted to take a shop rag with oil on it and use an unlit torch to blow O2 in the rag until it combusts. Now this feat (of possible stupidity) would occur in the middle of a gravel area. Would this be safe or STUPID? Now this has been on my mind for at least ten years but I don't do possibly stupid things on purpose. This thread just reminded me of it.
Reply:"Would this be safe or STUPID?"While you would be creating a very flammable object, wouldn't you still need an ignition source to get it to burst into flames?  I don't think blowing O2 onto oily rags would itself cause fire. Tim
Reply:lol.. do it.. better to regret doin than not doin..lolif you're not livin on the edge, you're takin up too much room..
Reply:Originally Posted by timrb"Would this be safe or STUPID?"While you would be creating a very flammable object, wouldn't you still need an ignition source to get it to burst into flames?  I don't think blowing O2 onto oily rags would itself cause fire. Tim
Reply:O2 also has a tendancy to "cling" to stuff. We had a safety instructor from one of the major brand blowtorch manufacturers (Harris I think) demonstrate this at the school I went to. He took a steel plate, put some metal shavings on it, then sprayed some 3 in 1 oil on it and hosed it with some pure oxygen. Then he let it set while he talked about oxygens tendancy to stick to stuff. After a couple minutes he took a hammer and ht the plate, BANG! The oxygen saturated oil ignites from the pressure of the hammer on the metal shavings. Pretty cool. Lessons learned, oil and oxygen don't mix, oxygen clings, and blow torches are fun.
Reply:Air Liquid does a little petroleum and O2 demo at their bbq and it is only a drop of petroleum, but the explosion is VERY large.
Reply:So........... is it stupid? Awe nevermind, not enough "it is completely safe, Stick-man" replies. Maybe I will, submit it to Mythbusters after all."Where's Stick man????????" - 7A749"SHHHHHH!! I sent him over to snag that MIC-4 while tbone wasn't looking!" - duaneb55"I have bought a few of Tbone's things unlike Stick-Man who helps himself" - TozziWelding"Stick-man"
Reply:Of course no ones going to suggest your idea is safe Stick-man. All we would need is some noob to read this thread and go try it in unsafe conditions and get himself hurt. I've been temted to try the same experiment, I just haven't had what i felt were safe conditions to conduct it.
Reply:Do it....How bad could it be?...We're talkin one small shop rag here, not a thermonuclear device---Put it on the concrete and do it.....
Reply:As TEK said, go ahead.I don't believe anything will happen.Except for some O2 being wasted.Just in case, control the O2 flow from a distance.Good Luck
Reply:Just to put in perspective the demo I saw was about a tea spoon of petroleum and a little pure 02 and the explosion would have easily taken a finger or 2 off.  It was a good safety demo and probably hard to duplicate in the working environment but I guess it has happened before...Be sure and video the experiment for all to see..
Reply:Posted by Denrep:As TEK said, go ahead.I don't believe anything will happen.Except for some O2 being wasted.Just in case, control the O2 flow from a distance.Good Luck
Reply:do it!... damn *****.. it's a rag... lolif you're not livin on the edge, you're takin up too much room..
Reply:Isnt welding 02 a higher purity than medical 02??  Also reminds me of a funny story at work.  We had a welding inspector come out to the field to UT some pipe for us.  He saw one of the guy's blowing out the whip on his LN-25 using his torch and freaked out.  He got out his soapbox and preached to us how EXPLOSIVE pure oxygen is.2011 Dodge 3500 diesel duallyLincoln SA-200Lincoln SAE-300LN-25'sLincoln Idealarc R3RMiller Trailblazer 302
Reply:When I was in the service I operated a liquid O2 plant. When we pumped Medical o2 it was 99.5% We pumped the same 99.5 in the welding cylinders although we could pump 96% for welding.sgCorrection 97% for welding O2Last edited by steveg; 02-27-2010 at 03:36 PM.