Posted by MHK on July 23, 2001 at 10:30:25:
In Reply to: Re: You obviously missed the entire point!!!!!!! posted by steve on July 23, 2001 at 09:28:57:
Steve,
I'm not putting down your experience, I'm putting it into context.. That's perfectly fair when you suggest that I'm giving potentially fatal advise..
If you are going to make that charge, you damn well better know what you are talking about first..
I put your experience into context because it is important to note that given the totality of the advise given on this list, the FFM was the most potentially fatal and it was based on aquarium experience..
Now to speak to the 02 issue what you are missing in alot.
Bill Hamilton is by-in-large credited with the creation of the Repex method back in the 80's.. Much like the 130' rule that came into being that theories abound but recreational diver's got stuck with, the NOAA 1.6 for 45 minutes came about during thses studies and they appear cast in stone ever since.. That ignores 20+ years of research and fly's directly in the face of current thinking..
For certain, oxygen toxicity is serious business, no question and I don't dismiss it for a second. If you look to the NOAA exposure limits you'll notice a few things:
1.6 45 minutes
1.5 120 minutes
1.4 150 minutes
1.3 180 minutes
1.2 210 minutes
1.1 240 minutes
Do you think that the 1/2 hour increments are coincidental, theoretical or approximate???
You need to look at why???? You need to look at why the jump from 45 minutes to 120 at 1.6 -v- 1.5.. Do you know why??? Did you review the studies??? You need to read the REPEX papers and you'll understand why.. I can't teach a whole Nitrox class on the internet, and I was led to believe that you had some TDI training, didn't they cover this???
I mentioned about re-setting the 02 clock.. That is a VERY, VERY important concept that was NOT done in the REPEX studies... You need to look at why the vascular restriction issues are important at 1.6, and then by switching to a lower F02 you actually restart the 02 clock and more efficiently allow 02 to flow through your blood..
Even if you read Bret Gilliam and Tom Mount's book about mixed gas diving, this concept is covered..
Accordingly, you are correct in that I was pissed that you suggested that I give out potentially fatal advise and I responded in due kind..
I'll spend all day answering questions but if you cavalierly accuse me of trying to get someone killed I'll make sure that I defend my actions and I'll make sure that the readers can judge for themselves who is better equipped to be dispensing advise in the given subject matter..
Later