Deep air on OC vs. CCR

Mixaddict · 10th January 2007, 05:08

Quote: (Originally Posted by RonMicjan)

out of curiosity, why the twenty questions on narcosis?

Hi Ron,

Thanks for your thoughts. Have been doing some dives in locations where helium in unavailable (or at least very difficult to get!) For me personally, it has seemed while diving CCR that I have been feeling the narcosis at more shallow depths than I typically do on OC, and basically wondered if other divers felt the same way. But here again, as you well know, it comes and goes differently on different days! My suscpicion is that the perceived narcosis level increase on CCR for me is possibly more about task loading than actual narcosis increase?

Anyway, just mostly curious. Usually, if I am going deeper than 140 feet on CCR, I squirt some helium in the dill. On OC, I am usually comfortable with going quite a bit deeper (subject to conditions.)

Interesting thoughts on the O2 not contributing to the narcosis. As you are aware there are a couple of schools of thought on this topic. I am going to give your experiment a try next time I'm out.

Regards,
Randy

GKAM · 10th January 2007, 09:54

Quote: (Originally Posted by Mixaddict)

...Have been doing some dives in locations where helium in unavailable (or at least very difficult to get!) For me personally, it has seemed while diving CCR that I have been feeling the narcosis at more shallow depths than I typically do on OC, and basically wondered if other divers felt the same way. But here again, as you well know, it comes and goes differently on different days! My suscpicion is that the perceived narcosis level increase on CCR for me is possibly more about task loading than actual narcosis increase?

Hi Randy,

I tend to agree. A 50m CCR dive on air dil makes me feel more narked than OC every time. I used to do a lot of OC deep air with bounce dives up to 100m. Over the years my ppN2 tolerance has decreased dramatically (or i have become much wiser). Nowadays my cut-off point is 50m for both OC and CCR on air.

On very good conditions, I still may spike down to 65-70m for a short while when on OC. IMHO, ppO2 exposue is not a real problem on OC air - at least to my own physiology. I have clocked many hours on O2 CCR at ppO2 values comparable to deep air with no problems.

The real problem is handling ppN2.

/GKAM

Mark Chase · 10th January 2007, 20:14

Quote: (Originally Posted by Mixaddict)

Hi Ron,

Thanks for your thoughts. Have been doing some dives in locations where helium in unavailable (or at least very difficult to get!) For me personally, it has seemed while diving CCR that I have been feeling the narcosis at more shallow depths than I typically do on OC, and basically wondered if other divers felt the same way. But here again, as you well know, it comes and goes differently on different days! My suscpicion is that the perceived narcosis level increase on CCR for me is possibly more about task loading than actual narcosis increase?

Anyway, just mostly curious. Usually, if I am going deeper than 140 feet on CCR, I squirt some helium in the dill. On OC, I am usually comfortable with going quite a bit deeper (subject to conditions.)

Interesting thoughts on the O2 not contributing to the narcosis. As you are aware there are a couple of schools of thought on this topic. I am going to give your experiment a try next time I'm out.

Regards,
Randy

I dived OC single tank to 35m out in Cuba in March 06 I was down there thinking "what is this strange feeling i feel all odd?" then it dawned on me i was feeling Narcosis. Having not dived OC 30m+ for about a year prior to this I had forgotten what it was like. I dive 18/45 for everything down to 50 and 14/65 past that so I am no longer used to feeling narked.

ATB

Mark Chase

***jradomski*** · 11th January 2007, 09:28

Quote: (Originally Posted by RonMicjan)

not even close, there is not nearly the PPn2 in the loop until you get to the "matching" depth, do the math and see what the PPn2 is at various depths at a constant setpoint.

Any one who tells you that oxygen is as narcotic as nitrogen has never dived a CCR, try this experiment, take your unit to depth with a low setpoint, say 130fsw and a sp of .4, (you will have to sit and breathe it down a while) think about your narcotic level, estimate the level of "fog", "rapture" "stupidity" or whatever version of narcosis you personally feel. Then, bump the PO2 up to 1.4 or so and watch the fog roll away, like your sittin on the dock o' the bay. Of course, dont be hangin around at 130 on a .4 too long, and make sure you are tracking deco with a dive computer set to whatever you are breathing.

next experiement, do the same drill and after the loop is resting at .4, then flush the loop with 20/50 and REALLY see the fog roll away. air for dil? NOT!

out of curiosity, why the twenty questions on narcosis?

BTW, I have done air OC to 276, had an awesome encounter with an electric ray (at least I think I did

) back when I was young and stupid. Now air OC is limited to OW instruction depths and shallow salvage and body recovery dives. The vast majority of diving is done CCR on 20/30 to about 150ish and 10/50 deeper. I like to keep an END of around 100fsw or PN2 of 3.2 ish.

HELIUM is your FRIEND!

I usually do this with people a bit deeper, usually around 150fsw, since you dont have to breath the loop down as much to get a good narc, then bringing it up to 1.4ish makes a big difference even though it doesnt fully clear up for many divers..

I'm not going to say oxygen is not narcotic at all, but I am willing to say its considerably less than the nitrogen it is replacing..

This is something than can easily be experienced by CCR divers, All the OC divers that say o2 narcosis is the same as n2 narcosic have never done an experiment that can easily prove this is the case, unfortunately we cant measure how narcotic the o2 is, but my feeling is is that the narcosis contribution by oxygen is so low that treating it as non narcotic reaaly isnt a problem, unless you are right on the edge for the depth your at....

***jradomski*** · 11th January 2007, 09:35

Quote: (Originally Posted by RonMicjan)

BTW, I have done air OC to 276, !

BTW I am willing to admit when I was young and stupid, I did an even stupider dive..

Both of the "magic" numbers that Imperial and Metric divers shoot for, in that order..

NOT RECOMMENDED!!!!!!

pete611 · 14th January 2007, 00:44

Hello from puerto rico i dive oc on air to 180'- 190' and on rebreather i will dive to 140' - 150' on the scc dolphin.

only warm water for me please....

RAL · 14th January 2007, 02:37

Quote: (Originally Posted by Mixaddict)

For me personally, it has seemed while diving CCR that I have been feeling the narcosis at more shallow depths than I typically do on OC, and basically wondered if other divers felt the same way. But here again, as you well know, it comes and goes differently on different days! My suscpicion is that the perceived narcosis level increase on CCR for me is possibly more about task loading than actual narcosis increase?

Regards,
Randy

I wonder if you may be getting narced shallower on CC than OC due to a bit of co2 getting passed the scrubber? For me one of the bigger factors in narcosis is co2 build up in my hat. If I start working hard on deep air I will get a bit of a buzz going till I crack the free flow. 150' with co2 build up feels deeper than 220' to me.

RAL

RonMicjan · 14th January 2007, 23:18

you would normally not get co2 buildup in the loop unless you were breathing incorrectly, the pn2 on the inhale side of the loop is less than ambient air, like about 0ppm (parts per million) until the scrubber begins to break through, then you get little spikes of 1- several hundred as the scrubber nears breakthrough. so CO2 is not inducing narcosis unless you are a co2 retainer.

10th January 2007, 05:08	#31 (permalink)
Mixaddict Always Learning! Current Rebreather/s: Inspiration Vision Evolution Other CCR Dolphin Other Rebreather/s: Inspiration Classic Other CCR Dolphin Join Date: Jan 2006 Location: Draper, Utah USA Posts: 454	Re: Deep air on OC vs. CCR Quote: (Originally Posted by RonMicjan) out of curiosity, why the twenty questions on narcosis? Hi Ron, Thanks for your thoughts. Have been doing some dives in locations where helium in unavailable (or at least very difficult to get!) For me personally, it has seemed while diving CCR that I have been feeling the narcosis at more shallow depths than I typically do on OC, and basically wondered if other divers felt the same way. But here again, as you well know, it comes and goes differently on different days! My suscpicion is that the perceived narcosis level increase on CCR for me is possibly more about task loading than actual narcosis increase? Anyway, just mostly curious. Usually, if I am going deeper than 140 feet on CCR, I squirt some helium in the dill. On OC, I am usually comfortable with going quite a bit deeper (subject to conditions.) Interesting thoughts on the O2 not contributing to the narcosis. As you are aware there are a couple of schools of thought on this topic. I am going to give your experiment a try next time I'm out. Regards, Randy __________________ Randy Thornton (MixAddict) Inspiration, Evolution,Hammerhead & Sentinel CCR Instructor
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10th January 2007, 09:54	#32 (permalink)
GKAM digital nomad Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: May 2005 Location: Greece Posts: 251	Re: Deep air on OC vs. CCR Quote: (Originally Posted by Mixaddict) ...Have been doing some dives in locations where helium in unavailable (or at least very difficult to get!) For me personally, it has seemed while diving CCR that I have been feeling the narcosis at more shallow depths than I typically do on OC, and basically wondered if other divers felt the same way. But here again, as you well know, it comes and goes differently on different days! My suscpicion is that the perceived narcosis level increase on CCR for me is possibly more about task loading than actual narcosis increase? Hi Randy, I tend to agree. A 50m CCR dive on air dil makes me feel more narked than OC every time. I used to do a lot of OC deep air with bounce dives up to 100m. Over the years my ppN2 tolerance has decreased dramatically (or i have become much wiser). Nowadays my cut-off point is 50m for both OC and CCR on air. On very good conditions, I still may spike down to 65-70m for a short while when on OC. IMHO, ppO2 exposue is not a real problem on OC air - at least to my own physiology. I have clocked many hours on O2 CCR at ppO2 values comparable to deep air with no problems. The real problem is handling ppN2. /GKAM __________________ Stay #
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10th January 2007, 20:14	#33 (permalink)
Mark Chase I go down for ages Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Jan 2005 Location: Kent Posts: 2,556	Re: Deep air on OC vs. CCR Quote: (Originally Posted by Mixaddict) Hi Ron, Thanks for your thoughts. Have been doing some dives in locations where helium in unavailable (or at least very difficult to get!) For me personally, it has seemed while diving CCR that I have been feeling the narcosis at more shallow depths than I typically do on OC, and basically wondered if other divers felt the same way. But here again, as you well know, it comes and goes differently on different days! My suscpicion is that the perceived narcosis level increase on CCR for me is possibly more about task loading than actual narcosis increase? Anyway, just mostly curious. Usually, if I am going deeper than 140 feet on CCR, I squirt some helium in the dill. On OC, I am usually comfortable with going quite a bit deeper (subject to conditions.) Interesting thoughts on the O2 not contributing to the narcosis. As you are aware there are a couple of schools of thought on this topic. I am going to give your experiment a try next time I'm out. Regards, Randy I dived OC single tank to 35m out in Cuba in March 06 I was down there thinking "what is this strange feeling i feel all odd?" then it dawned on me i was feeling Narcosis. Having not dived OC 30m+ for about a year prior to this I had forgotten what it was like. I dive 18/45 for everything down to 50 and 14/65 past that so I am no longer used to feeling narked. ATB Mark Chase __________________ Is it supposed to make that noise ? I took my unit to the dive shop and demanded they bolt on every thing that would fit. Join my elite diving teem and get a Tshirt "Doing It Chasey"Hammerhead Eccr Advanced Diving System
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11th January 2007, 09:28	#34 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Home Build Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Home Build Join Date: Mar 2005 Location: "Da" Bronx Posts: 2,885	Re: Deep air on OC vs. CCR Quote: (Originally Posted by RonMicjan) not even close, there is not nearly the PPn2 in the loop until you get to the "matching" depth, do the math and see what the PPn2 is at various depths at a constant setpoint. Any one who tells you that oxygen is as narcotic as nitrogen has never dived a CCR, try this experiment, take your unit to depth with a low setpoint, say 130fsw and a sp of .4, (you will have to sit and breathe it down a while) think about your narcotic level, estimate the level of "fog", "rapture" "stupidity" or whatever version of narcosis you personally feel. Then, bump the PO2 up to 1.4 or so and watch the fog roll away, like your sittin on the dock o' the bay. Of course, dont be hangin around at 130 on a .4 too long, and make sure you are tracking deco with a dive computer set to whatever you are breathing. next experiement, do the same drill and after the loop is resting at .4, then flush the loop with 20/50 and REALLY see the fog roll away. air for dil? NOT! out of curiosity, why the twenty questions on narcosis? BTW, I have done air OC to 276, had an awesome encounter with an electric ray (at least I think I did ) back when I was young and stupid. Now air OC is limited to OW instruction depths and shallow salvage and body recovery dives. The vast majority of diving is done CCR on 20/30 to about 150ish and 10/50 deeper. I like to keep an END of around 100fsw or PN2 of 3.2 ish. HELIUM is your FRIEND! I usually do this with people a bit deeper, usually around 150fsw, since you dont have to breath the loop down as much to get a good narc, then bringing it up to 1.4ish makes a big difference even though it doesnt fully clear up for many divers.. I'm not going to say oxygen is not narcotic at all, but I am willing to say its considerably less than the nitrogen it is replacing.. This is something than can easily be experienced by CCR divers, All the OC divers that say o2 narcosis is the same as n2 narcosic have never done an experiment that can easily prove this is the case, unfortunately we cant measure how narcotic the o2 is, but my feeling is is that the narcosis contribution by oxygen is so low that treating it as non narcotic reaaly isnt a problem, unless you are right on the edge for the depth your at.... __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated. Last edited by jradomski : 11th January 2007 at 09:32.
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11th January 2007, 09:35	#35 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Home Build Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Home Build Join Date: Mar 2005 Location: "Da" Bronx Posts: 2,885	Re: Deep air on OC vs. CCR Quote: (Originally Posted by RonMicjan) BTW, I have done air OC to 276, ! BTW I am willing to admit when I was young and stupid, I did an even stupider dive.. Both of the "magic" numbers that Imperial and Metric divers shoot for, in that order.. NOT RECOMMENDED!!!!!! __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated.
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14th January 2007, 00:44	#36 (permalink)
pete611 RBD one dive at a time... Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Feb 2006 Location: Puerto Rico Posts: 223	Re: Deep air on OC vs. CCR Hello from puerto rico i dive oc on air to 180'- 190' and on rebreather i will dive to 140' - 150' on the scc dolphin. only warm water for me please....
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14th January 2007, 02:37	#37 (permalink)
RAL Longbottom Time Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Jan 2006 Location: North Florida Posts: 386	Re: Deep air on OC vs. CCR Quote: (Originally Posted by Mixaddict) For me personally, it has seemed while diving CCR that I have been feeling the narcosis at more shallow depths than I typically do on OC, and basically wondered if other divers felt the same way. But here again, as you well know, it comes and goes differently on different days! My suscpicion is that the perceived narcosis level increase on CCR for me is possibly more about task loading than actual narcosis increase? Regards, Randy I wonder if you may be getting narced shallower on CC than OC due to a bit of co2 getting passed the scrubber? For me one of the bigger factors in narcosis is co2 build up in my hat. If I start working hard on deep air I will get a bit of a buzz going till I crack the free flow. 150' with co2 build up feels deeper than 220' to me. RAL __________________ The sea does not care about you.
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14th January 2007, 23:18	#38 (permalink)
RonMicjan Cap Ron scourge of the NW Current Rebreather/s: Megalodon Dolphin Home Build Other Rebreather/s: Sport Kiss Classic Kiss Dolphin Home Build Join Date: Feb 2005 Location: Cape Disapointment, The Graveyard of the Pacific Posts: 1,082	Re: Deep air on OC vs. CCR you would normally not get co2 buildup in the loop unless you were breathing incorrectly, the pn2 on the inhale side of the loop is less than ambient air, like about 0ppm (parts per million) until the scrubber begins to break through, then you get little spikes of 1- several hundred as the scrubber nears breakthrough. so CO2 is not inducing narcosis unless you are a co2 retainer. __________________ Ron "Life is pain princess, anyone who tells you different, is selling something", The Dread Pirate Wesley. www.tmishop.com Diving bits etc.
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