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We use 50% CO2 in our 120% O2 mixes to reduce the chance of fire during a dive. The only thing we have noticed is that we are always so tired at depth. But, the amphetamines we get from the truck stop on the way to the dive keeps us on track. During a dive I really love to make the jelly fish go through their pulsating routines over and over and over and over again. I could just watch for hours and hours and hours and hours and hours and hours and hours as they move back and forth and back and forth and back and forth and back and forth and over and over and over and over again. On Fri, 23 Aug 1996, John Gibbons wrote: > > I personaly believe that oxygen cleaning cylinders and regulators is not > enough, not only should the breathing loop of your rebreather be O2 clean > and compatible but so should your lungs. Before every dive that I am > going to be breathing 80% O2 to deco on I make sure that I swill out my > lungs with Trike to get rid of all those anoying hydrocarbon build-ups > you get living in the big city. Not only do I find that the peace of mind > this brings me knowing that the chance of my lungs suffering an oxygen > fire but it also helps reduce my air consumption. > > I started doing this after a friend of mine a terrible accident while > diving on a 50% O2 mix and using it to inflate his drysuit. We had been > out the night before in Plymouth and had gotten pretty wasted. As most > people in the UK know the only way to finish of a good night out drinking > is with a nice Ruby (Curry to those across the pond). So my friend Dave > and I find ourselves in Mr Rajs at about 2 am. After a few more pints, a > popadom or two we begin the main event....one chicken vindaloo, one beef > phal, and an order of Bombay potatoes and some sag aloo. > The next day were feeling a little rough and Dave's guts are giving a bit > of grief. I got him into his drysuit as soon as possible to try to > contain some of the gas that he was producing. I swear it smelled like > something had died inside him and was slowly rotting. > > We roled off the back of the boat and headed for the bottom. As we > went down Dave was putting air into his drysuit from the 50% on his back, > the next thing I see is Dave suit puff outwards and then explode in a > ball of flame. > > The coroners report said that the gas build up in the suit must have > reacted with the oxygen frying him. The worst thing was they said was the > blow back which caused him to explode from the inside. Not a pretty site. > > >From then on I started the lung fluxhing and curry ban when breathing any > gas other that air, I'm just not willing to take the risk. > > You wont read about this in the press as it was covered up by the dive > center and is part of an overall conspiracy concerning diving independant > cylinders, hose stuffing, square lights, bondage wings, redundant > bladders, diving high ppO2, and O2 cleaning of equipment and sushi eating. > > So the next time you go diving think about what you eat before hand. > > John Gibbons > Spiritual advisor to: > Westminster and North Kensington Sub-Aqua Club > > > > > > i) do rebreather users have to O2 clean the entire loop? > > > > I don't. Obviously, fires can burn much brighter and hotter in high-O2 > > environments; however, in diving we are not nearly as concerned with a > > fire in-progress as we are in *igniting* a fire. Spontaneous ignition > > seems to require a combination of high PO2 *and* high FO2, so I only > > worry about it with pure O2 above 500psi. I don't worry about it with any > > nitrox mixture because I never make nitrox mixtures with more than about > > 30-40% O2. At higher percentages, I would be more careful. > > > > > ii) NASA started all the O2 work, didn't they, after Apollo 1 &/ > > > 13 - why did they come up with an fO2 40% as a critical point? > > > > Good question. Someone once told me, but I have since forgotten. > > > > > iii) saying O2 fires don't happen at low pressures is fine; tell > > > the guys starting their oxyacetaline rigs from grease patches. > > > > See above - it's not the fire we're worried about as much as the > > potential for ignition. I'm not an expert, but it is my understanding > > that most materials have very high ingition temperatures, so are not > > likely to combust. Hydrocarbons, however, have very low ignition > > temperatures, so they are more likely to combust. A drop of oil in your > > O2 regulator is not going to explode. It might, however, combust and > > raise the local temperature high enough to ignite other materials (like > > SS or brass), leading to a fire. > > > > Aloha, > > Rich > > > > > iv) as bill said, 'it ain't happened yet' is not *quite* good > > > enough. When a very nice Thai started to fill his tuk-tuk from a petrol > > > pump with the lit cigarette *in that hand* we were the other side of the > > > building before you could say 'badoom'. He found it very funny. > > > > -- > Send mail for the `techdiver' mailing list to `techdiver@terra.net'. > Send subscription/archive requests to `techdiver-request@terra.net'. >
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