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>Last fall, we had a great discussion on this forum about whether or not we >need to clean hardware and replace soft goods (o-rings and grease) to make >it O2 service. > >I am just coming back from Florida where I completed my training as Full >Cave diver. I had the opportunity to dive on Nitrox and decompress on O2 >and some friends took a Nitrox Diver course. What I've seen is that what is >taught in a class often differ greatly from what is done. I saw people >putting pure O2 in non cleaned tanks and topping air over O2 with various >compressors (which didn't look like O2 compatible compressors). > >When I came back from there, I took some time to visit a few places around >here. I asked an o-ring distributor for Viton o-rings. He asked me why and >at what temperature they will be used (after all, it might be too expensive >for nothing he said). I said that I need O2 compatible o-rings to use at >ambiant temperature and high pressure (3000-3500 psi). He said that Viton >is not required if I do not use O2 at high temperature (more than 200F or >95C). He suggested me to go with Nitrile or Neoprene (sounds like standard >stuff). He also told me that Viton will be bad because of the utilisation >temperature (we still dive when it is minus 20 and Viton o-rings are not >good below minus 15). I was a little bit surprised with his comments. > >Then, I visited another place which distribute gas and welding equipment. I >asked how they maintain the O2 welding regulator and what type of o-rings >they put into these. He guy told be that he puts neoprene o-rings in most >regulator brands. > >If all of this is true, why do training agencies require us to modify the >tank valves, etc. Is this for commercial reasons? I did not ask about the >lubricants. Is it required to use a special lubricant or not? > >I always thought that it was required to put O2 compatible soft goods in >valves and regulators but according to what I heard, neoprene would be >compatible at ambiant temperature... > >Can someone clarify this issue? > >Michel >MTHERRIEN@sh*.mo*.mm*.sh*.co* > >-- >Send mail for the `techdiver' mailing list to `techdiver@opal.com'. >Send subscription/archive requests to `techdiver-request@opal.com'. Michel: I recently posted a note concerning an accident and explosion which occurred to a good friend who was very lucky and only suffered some small 3rd degree burns in the process. He was filling, actually topping off, a bottle of pure O2 to make EAN 80 for deco. His transfer whip broke, the pure O2 leaked and came into contact with the hose which was not "O2" compatible. A fire and explosion ensued. He was very lucky as the tank and whip which acted like a blow torch after the explosion, were directly under his new car and its gas tank! Conclusion: For me, I'm a believer in O2 cleaning of tanks, regulators, hoses and all if it's going to be used in high O2 concentration situations especially if the pressure is high as well. You may get away with using non compatible gear for years, then..... next time my friend might not be so lucky. He's now a believer, by the way! Harold Gartner hgartner@ra*.or* CompuServe ID 71470,1423 6900 Via Alba Camarillo, California 805 482-9743
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