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**Dave Sutton** · 28th January 2007, 23:52

Quote: (Originally Posted by chunter)

I The real question is how long does it take you to breathe down a 2.5 to a 1.3 or better yet, to flush a 4.0 down to a 1.3?

Errr..... *nobody* ever suggested diving with a diluent that had a 2.5 or 4.0 PP02 on the bottom so *get real*. Any point can be taken to the area of senselessness. What I *suggested* is that we not switch to hypoxic diluents *unless we need them* and then further suggested that we don't need them as shallow as some think. I fence off my max depth for normoxic diluents when I reach 1.8 PP02 on the bottom, and run 20% dils to the associated depths for that. After that we switch to hypoxic dils. And it's *darned rare* for us to be in the depth band where we exceed setpoint PP02 with 20% and have not yet switched to hypoxic dils. Like 1 in 100 dives......

2.5? 4.0? Nobody ever said that was appropriate. Maybe you got bored and skipped over the technical parts in the earlier series.... and the KISS has a valve on the 02 bottle for a reason......

And the title of the thread is wrong:

NOBODY INCLUDING ME HAS PROPOSED THE DELIBERATE USE OF HOT DILUENTS.

Can I make it any clearer than that?

All I have EVER said is that we should not use hypoxic diluents *unless required* as they:

(1) disallow us certain important SCC bailout modes,

(2) hurt our deco possibilities using our dil open circuit,

(3) have hypoxia/drowning potential if an ADV fails open or we get unwanted diluent into the loop near the surface (and read the current Inspiration thread on that issue it's a REAL one...). And no joke: With the reports of undesired diluent freeflows into the loop, this could KILL YOU RIGHT NOW!

GUYS: If you get an ADV freeflow, (which is *far* more common than many other "silly bordering on insane" hypotheticals than people propose here,) you're not gonna tolerate 10% diluent in your loop on the surface for more than a few *moments* before doing the dead-fly routine *just moments before you drown* after your DSV slips from your unconcious mouth and you loose all of that nice bouyancy in the loop as it floods in about 5 seconds... Trust me on this, *please*?? as I've seen it for *real* (except we dived in and saved his sorry butt and now he buys me beer and mixes his 20% diluent with a smile)

etc.

I also *mentioned* that I will *TOLERATE* (not "desire") diluent that is SLIGHTLY hotter than my desired setpoint *for a certain small fraction of my dives* before I switch to hypoxic diluents for the aformentioned reasons, as I will reduce the PP02 by normal metabolism LONG BEFORE THE CNS CLOCK does jack-shi@ to me. I *personally* use 1.8 as my cut-off, feel free to use 1.6 or 1.4, whatever runs your CNS clock.... Get it?

Dave

28th January 2007, 23:52	#8 (permalink)
Dave Sutton Diveshop of Horrors Current Rebreather/s: Sport Kiss MK 15.X rEvo Other CCR Azimuth Home Build Other Rebreather/s: Classic Kiss rEvo Other CCR Azimuth Home Build Join Date: Jun 2006 Location: Narragansett, Rhode Island and Hackettstown, New Jersey Posts: 2,672	Re: Use of 'hot' diluents Quote: (Originally Posted by chunter) I The real question is how long does it take you to breathe down a 2.5 to a 1.3 or better yet, to flush a 4.0 down to a 1.3? Errr..... nobody ever suggested diving with a diluent that had a 2.5 or 4.0 PP02 on the bottom so get real. Any point can be taken to the area of senselessness. What I suggested is that we not switch to hypoxic diluents unless we need them and then further suggested that we don't need them as shallow as some think. I fence off my max depth for normoxic diluents when I reach 1.8 PP02 on the bottom, and run 20% dils to the associated depths for that. After that we switch to hypoxic dils. And it's darned rare for us to be in the depth band where we exceed setpoint PP02 with 20% and have not yet switched to hypoxic dils. Like 1 in 100 dives...... 2.5? 4.0? Nobody ever said that was appropriate. Maybe you got bored and skipped over the technical parts in the earlier series.... and the KISS has a valve on the 02 bottle for a reason...... And the title of the thread is wrong: NOBODY INCLUDING ME HAS PROPOSED THE DELIBERATE USE OF HOT DILUENTS. Can I make it any clearer than that? All I have EVER said is that we should not use hypoxic diluents unless required as they: (1) disallow us certain important SCC bailout modes, (2) hurt our deco possibilities using our dil open circuit, (3) have hypoxia/drowning potential if an ADV fails open or we get unwanted diluent into the loop near the surface (and read the current Inspiration thread on that issue it's a REAL one...). And no joke: With the reports of undesired diluent freeflows into the loop, this could KILL YOU RIGHT NOW! GUYS: If you get an ADV freeflow, (which is far more common than many other "silly bordering on insane" hypotheticals than people propose here,) you're not gonna tolerate 10% diluent in your loop on the surface for more than a few moments before doing the dead-fly routine just moments before you drown after your DSV slips from your unconcious mouth and you loose all of that nice bouyancy in the loop as it floods in about 5 seconds... Trust me on this, please?? as I've seen it for real (except we dived in and saved his sorry butt and now he buys me beer and mixes his 20% diluent with a smile) etc. I also mentioned that I will TOLERATE (not "desire") diluent that is SLIGHTLY hotter than my desired setpoint for a certain small fraction of my dives before I switch to hypoxic diluents for the aformentioned reasons, as I will reduce the PP02 by normal metabolism LONG BEFORE THE CNS CLOCK does jack-shi@ to me. I personally use 1.8 as my cut-off, feel free to use 1.6 or 1.4, whatever runs your CNS clock.... Get it? Dave __________________ "Changes in Lattitudes, Changes in Attitudes, Nothing remains quite the same".... www.nobubblediving.com Last edited by Dave Sutton : 29th January 2007 at 00:13.
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