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I know what you mean . I need to get over worrying about it. I probably would have let these guys stew in their own stupidity had one of them not made it personal. armantrout@at*.ne* wrote: > > I just don't have the motivation to correct the people > who already "know it all", and everybody else just comes > to us to find out the real story anyway. So what's the > use? > > > Totally and completely untrue - Martin you need to knock it of. You are > > not even remotely close to being right about any of this - not even > > close. You are one serious idiot for getting on here wiht thin sdegeree > > of misinformation. > > > > Can some of the other WKPP guys who know what they ar talking about take > > over on this one - there are too many idiots spouting on this list right > > now for me to field enverything - need some help here. > > > > Martin M. Quigley wrote: > > > > > > Scott - > > > The "oxygen clock" is a useful concept to think about the body's > > > accumulation of oxygen toxicity over time. There are two principal type of > > > oxygen toxicity - pulmonary and CNS. Pulmonary oxygen toxicity starts to > > > occur with long-term breathing (over 24 hours) of oxygen at a partial > > > pressure over 0.5. The higher the partial pressure of oxygen, the shorter > > > exposure time required before pulmonary oxygen toxicity begins to develop. > > > Pragmatically, a recreational "technical" diver generally doesn't have to > > > worry about pulmonary oxygen toxicity unless he/she needs to undergo > > > extensive recompression therapy (more than a Navy Table VI). > > > CNS toxicity is more critical. The higher the partial pressure, the > > > "faster" the oxygen toxicity clock runs. Exercise, carbon dioxide retention, > > > and other factors increase the susceptibility to CNS oxygen toxicity. The > > > NOAA limits I cited are "conservative" limits, based on some "wet" diving > > > human experimentation plus industry experience. In addition to the limits I > > > included (which are single dive limits), there are also 24-hour limits for > > > repetitive dives. Staying within these limits exposure a diver to a very low > > > risk of CNS oxygen toxicity. Exceeding a partial pressure of 1.6, even for a > > > few minutes, exposures a "working" diver to a very high risk of an oxygen > > > seizure. > > > My specific example (125 minute exposure to a ppO2 max of 1.4)is just > > an > > > example of the use of the tables. If you're going to be exposed to O2 over > > > 0.5 partial pressure on a dive for 125 minutes, you should limit the maximum > > > ppO2 at any point of the dive to 1.4. > > > Martin > > > > > > > -----Original Message----- > > > > From: ScottBonis@ao*.co* [mailto:ScottBonis@ao*.co*] > > > > Sent: Tuesday, February 08, 2000 6:42 PM > > > > To: quiglem@ib*.ne* > > > > Cc: techdiver@aquanaut.com > > > > Subject: Oxygen Limits > > > > > > > > > > > > Hi Martin, > > > > > > > > On 2/7/00 you wrote; > > > > << ... The 3rd Edition of the NOAA Manual (4th due out this month > > > > - but I don't expect changes) has time/pO2 limit tables for > > > > oxygen exposure for working divers as follows: > > > > SINGLE EXPOSURE Maximums: > > > > PPO2 ATA Minutes > > > > 1.6 45 > > > > 1.5 120 > > > > 1.4 150 > > > > 1.3 180 > > > > 1.2 210 > > > > (i.e., if your underwater time is planned for 125 minutes, the > > > > max. you can breath at any point in the dive is 1.4).... >> > > > > > > > > Could you please explain a little more about the parenthetical > > > > statement. How does this correlate with the concept of an "Oxygen clock?" > > > > > > > > Thanks a lot for your help. > > > > > > > > Scott > > > > > > > > > > > > > > -- > > > Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > > > Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. > > > > -- > > Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > > Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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