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Nelson, re: <snip> (Don't) try that with 36% Nitrox... <snip> I follow your logic on not using 36% Nitrox for deco at both 110' due to increased N2 ongassing instead of staying on helium, and your logic for using 50% at 70' instead of 36% for a more favorable ppO2. However I'm not understanding why you couldn't safely deco to the surface from 20' on 36% if your 100% 02 failed at 20'. Could you please clarify ? Thanks, Greg > ---------- > From: NPerry255@ao*.co*[SMTP:NPerry255@aol.com] > Sent: Saturday, November 04, 2000 1:10 PM > To: cytech@ma*.co*.cy*; techdiver@aquanaut.com > Subject: Re: Deco gas options/Follow-up > > Manos, > One other important operational consideration: if you have an > emergency > and completely lose your O2 at 20', you CAN deco to the surface on 50% O2 > (gas supply permitting). > (Don't) try that with 36% Nitrox... > > Safe diving, > Nelson Perry > -- > Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. > > ---------- > From: NPerry255@ao*.co*[SMTP:NPerry255@aol.com] > Sent: Friday, November 03, 2000 4:30 PM > To: cytech@ma*.co*.cy*; techdiver@aquanaut.com > Subject: Re: Deco gas options > > Manos, > I'll take a crack at this... (I used to use 36% Nitrox -- not > anymore!) > > 36% Nitrox at 110' is never preferred over 50% O2 at 70'... because: > > 1) your 110' stop is probably only 1 min., at the beneficial 1.6 PO2, but > even so, at 4+ ATA you are ingassing too much N2 switching off your helium > > bottom mix! It is better to stay on helium for your deep stops, anyway, > which off-gases better than N2 > > 2) by the time you are at 70', the PO2 of 36% Nitrox is too low to be very > > beneficial > > 3) by the time you are at 40' & 30', there is hardly any deco benefit > > 4) instead, getting on 50% O2 at 70' keeps a much better PO2 (and less > PN2!) > until your O2 at 20'... > > 5) finally, and very importantly, WKPP found out BY EXPERIENCE that using > 36%, they got bent (years ago); changing to 50% O2, they did not! > > Hopefully, I haven't mis-stated the reasons... > > Nelson Perry > -- > 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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