How much Deco

Captain Nemo · 17th February 2008, 15:48

Hi Tasa put a list together of dive times with a one minute stop at 4.5m. Diving with a 1.3 PPO2 and air diluent,ascending at ten metres a minute.

20m..181 mins
23m...90 mins
26m...60 mins
29m...45 mins
32m...30 mins
35m...25 mins
38m...20 mins
41m...20 mins
44m...15 mins
47m...15 mins
50m...12 mins

However if you want to do up to 15 mins deco.....

41m...35 mins
44m...30 mins
47m...28 mins
50m...25 mins

Hope this is of some help

teomannaskali · 17th February 2008, 17:47

I think that this was the answer that he was after.

Teoman

taza · 17th February 2008, 21:11

Cheers Guys for all the info,
Going over to Brets at Dive Life (Manchester UK)to look into booking MOD 1.
Its going to be at least six months before I can raise the cash for the unit,Bret has offered to hire me a unit to take the course early rather than later.

Cheers

Colin

Gobfish1 · 17th February 2008, 22:03

20m..181 mins = 100/180=.55*181=A cns of 101%

some may say its not safe ,,
23m...90 mins
26m...60 mins
29m...45 mins
32m...30 mins
35m...25 mins
38m...20 mins
41m...20 mins
44m...15 mins
47m...15 mins
50m...12 mins

However if you want to do up to 15 mins deco.....

41m...35 mins
44m...30 mins
47m...28 mins
50m...25 mins

but youre right that s what the man wanted on his first post ,,

Gobfish1 · 17th February 2008, 23:41

Quote: (Originally Posted by tekdiver170)

I have not gone as far as a full face mask. On my Rebreather I have done dives in the 150 min. range at a 1.3 in shallower water < 100' and so far have not had an issue. But I have not yet pushed the limits at 1.3.

This leads me to believe 2 things. One is that my body just doesn't like PO2 at a 1.6, or maybe it's diving at deeper depths that leads to my issues at a higher PO2. Most of my deeper dives have bottom times in the 30 min. range. I dive with OC divers so this is what they're able to do with the tank sizes we dive out here in Hawaii.

It's funny even though I've done 150 min+ dives on my Rebreather in shallower water with a PO2 of a 1.3 but it's our deco dives I get more nervous about an O2 hit while on my deco at a 1.25 for only around an hour.

hi chris

thanks for the replys ,,
makes good reading . just one Q you seem to spend a good few mins on you're 70f and 60f stops are you padding them out, to make best the o2 window ,, hi ppo2 at 70f and 60f , and you're ok,
hi ppo2 at last stop and you're not ok ,,, strange i must say ,,,

well i hope its all in the past for you, now you;re on the ccr , stay safe m8

ps
seen a few tiger sharks out in cuba, dont think i would want one as a pet ,,

Tino de Rijk · 19th February 2008, 12:18

I'm quite late in this discussion, but what the hell....

A.o. I am the chairman of the committee technical diving for a large non-commercial (CMAS-) diving federation called the NOB in the Netherlands, Europe (50 years old, 17000 members).
We are in the process of renewing/revamping our Advanced Nitrox training material & standards, and in that process we asked our Medical Committee (all doctors, amongst which the head of the Dutch Navy Dive-medical Center and a very experienced neurologist) for a view on CNS.

they dug deep in old "reference" material and proof and texts, a.o. the famous NOAA CNS tables. What they came up with in short was:

Scientifically speaking, there has not been much really worth-while research over the years on recreational divers for ox tox that is "convincing" or consistent.
There is a lot of copy-catting in newer "research" of old findings, without additional research for verification or developed new insights.
CNS% is a worthless thing. You can get into a convulsion way before 100%, or on the other hand tolerate 200%, depending on the circumstances. For that reason we will effectively drop CNS % calculations in our training material.
UPTD's will stand (and are more reliable, as the research there is done in the anestaesiology area over the years, also normobaric) but are not an acute danger for the diver, so as such another matter and not of inmediate interest here.
The MAJOR factor is PO2. There is no 100% guarantee in this (depending on personal susceptibility), but in general with PO2's of max. 1.4 and 1.5 your risks for convulsions are really quite low. So much so, that they dare to state that at a PO2 of 1.3 you could stay virtually limitless (i.e. exceed 100% CNS without problems). However, at or over 1.6 your risks are significant - regardless of time of exposure.

Susceptibility for PO2 while diving is majorly different than above water. E.g., a standard decochamber treatment these days is 18 meter, 100%O2, which is a whopping PO2 of 2.8 bar! And convulsions do not occur really often. But don't try this while diving...... :-)

So: within our federation, we will keep a max PO2 of 1.5 (normal max) or 1.4 (work, cold & training max) for exposure.
This all is regardless of OC or CCR: PO2 = PO2.

Hope this helps.

ciao,

Tino.

Quote: (Originally Posted by Gobfish1)

hi chris

thanks for the replys ,,
makes good reading . just one Q you seem to spend a good few mins on you're 70f and 60f stops are you padding them out, to make best the o2 window ,, hi ppo2 at 70f and 60f , and you're ok,
hi ppo2 at last stop and you're not ok ,,, strange i must say ,,,

well i hope its all in the past for you, now you;re on the ccr , stay safe m8

ps
seen a few tiger sharks out in cuba, dont think i would want one as a pet ,,

taza · 27th August 2008, 22:14

Right guys,
Just got my V Planner codes & key numbers so back to playing about with
different dive plans.

Mod 1 air as dil
Max depth 45mtr

What figures shall I put in the configure dive parameters.

Cheers

TAZA

toe · 28th August 2008, 14:16

Quote: (Originally Posted by taza)

Cheers Guys for all the info,
Going over to Brets at Dive Life (Manchester UK)to look into booking MOD 1.
Its going to be at least six months before I can raise the cash for the unit,Bret has offered to hire me a unit to take the course early rather than later.

Cheers

Colin

You would be amazed how much you will forget, if you can not start diving straight after course. Would say best to wait till you are nearER getting unit.
IMHO

Tony

**nigelh** · 28th August 2008, 14:42

Quote: (Originally Posted by Tino de Rijk)

Susceptibility for PO2 while diving is majorly different than above water. E.g., a standard decochamber treatment these days is 18 meter, 100%O2, which is a whopping PO2 of 2.8 bar! And convulsions do not occur really often. But don't try this while diving...

I have a feeling that we get convulsions because we expect convulsions. There is a strong psychological element.

"Oh grief. 1.5!!! I'm gonna die!!" panic panic twitch twitch.

When I started 1.6 was reasonable and 2.0 was the big no-no. In the chamber 2.8 might make you a bit trembly but they don't tell you your CNS just went over 500% so you don't get to worry. Anyway somebody else is in charge, we always like that.

I have promised myself that if the ppO2 goes over the top it is dil flush and chill. That feels best. If it goes low the trick adds a breath-hold as I know I can do three minutes apnea but I must not flush more oxygen out of my body before the loop is reasonable. If I get it wrong and die get my son to post the computer dump here so you can work out where I went amiss. (My friends are under instructions to flame me retrospectively if I win a Darwin underwater.)

taza · 28th August 2008, 19:39

Passed Mod 1 in April, done twenty dives on my baby,
Just got rid of AP harness and fitted Halycon S/Steel back plate.

Going out Saturday to give it a try, been walking round the garden with it on and feels much better.

Still would like to know what settings to put in the configure parameters.(v planner)

Cheers

Taza

17th February 2008, 15:48	#31 (permalink)
Captain Nemo RBW Member Current Rebreather/s: Evolution Other Rebreather/s: Not Bought Yet Inspiration Classic Inspiration Vision Evolution Megalodon Sport Kiss Classic Kiss Join Date: Oct 2006 Location: CORNWALL Posts: 55	Re: How much Deco Hi Tasa put a list together of dive times with a one minute stop at 4.5m. Diving with a 1.3 PPO2 and air diluent,ascending at ten metres a minute. 20m..181 mins 23m...90 mins 26m...60 mins 29m...45 mins 32m...30 mins 35m...25 mins 38m...20 mins 41m...20 mins 44m...15 mins 47m...15 mins 50m...12 mins However if you want to do up to 15 mins deco..... 41m...35 mins 44m...30 mins 47m...28 mins 50m...25 mins Hope this is of some help __________________ Look beyond the dark side into the light. Beware of false knowledge; It is more dangerous than ignorance.
(Offline)

17th February 2008, 17:47	#32 (permalink)
teomannaskali RBW Member Current Rebreather/s: Home Build Other Rebreather/s: Not Bought Yet Home Build Join Date: Feb 2006 Location: Istanbul TR Posts: 421	Re: How much Deco I think that this was the answer that he was after. Teoman
(Offline)

17th February 2008, 21:11	#33 (permalink)
taza New Member Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Vision Join Date: Jul 2007 Location: Warrington UK Posts: 87	Re: How much Deco Cheers Guys for all the info, Going over to Brets at Dive Life (Manchester UK)to look into booking MOD 1. Its going to be at least six months before I can raise the cash for the unit,Bret has offered to hire me a unit to take the course early rather than later. Cheers Colin
(Offline)

17th February 2008, 22:03	#34 (permalink)
Gobfish1 RBW Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Join Date: Apr 2005 Location: Manchester UK Posts: 410	Re: How much Deco 20m..181 mins = 100/180=.55181=A cns of 101% some may say its not safe ,, 23m...90 mins 26m...60 mins 29m...45 mins 32m...30 mins 35m...25 mins 38m...20 mins 41m...20 mins 44m...15 mins 47m...15 mins 50m...12 mins However if you want to do up to 15 mins deco..... 41m...35 mins 44m...30 mins 47m...28 mins 50m...25 mins but youre right that s what the man wanted on his first post ,, __________________ Steve G Apparently not the only gay diver in the village http://drinkingliberally.org/blogs/o...nzee-glock.gif http://www.scubatunes.com/audio/vol01/mp3/HiTech.mp3 Last edited by Gobfish1 : 17th February 2008 at 22:07.*
(Offline)

17th February 2008, 23:41	#35 (permalink)
Gobfish1 RBW Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Join Date: Apr 2005 Location: Manchester UK Posts: 410	Re: How much Deco Quote: (Originally Posted by tekdiver170) I have not gone as far as a full face mask. On my Rebreather I have done dives in the 150 min. range at a 1.3 in shallower water < 100' and so far have not had an issue. But I have not yet pushed the limits at 1.3. This leads me to believe 2 things. One is that my body just doesn't like PO2 at a 1.6, or maybe it's diving at deeper depths that leads to my issues at a higher PO2. Most of my deeper dives have bottom times in the 30 min. range. I dive with OC divers so this is what they're able to do with the tank sizes we dive out here in Hawaii. It's funny even though I've done 150 min+ dives on my Rebreather in shallower water with a PO2 of a 1.3 but it's our deco dives I get more nervous about an O2 hit while on my deco at a 1.25 for only around an hour. hi chris thanks for the replys ,, makes good reading . just one Q you seem to spend a good few mins on you're 70f and 60f stops are you padding them out, to make best the o2 window ,, hi ppo2 at 70f and 60f , and you're ok, hi ppo2 at last stop and you're not ok ,,, strange i must say ,,, well i hope its all in the past for you, now you;re on the ccr , stay safe m8 ps seen a few tiger sharks out in cuba, dont think i would want one as a pet ,, __________________ Steve G Apparently not the only gay diver in the village http://drinkingliberally.org/blogs/o...nzee-glock.gif http://www.scubatunes.com/audio/vol01/mp3/HiTech.mp3 Last edited by Gobfish1 : 18th February 2008 at 01:41.
(Offline)

19th February 2008, 12:18	#36 (permalink)
Tino de Rijk Old, maybe one day wise Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Evolution Join Date: Mar 2006 Location: Amsterdam Posts: 375	Re: How much Deco I'm quite late in this discussion, but what the hell.... A.o. I am the chairman of the committee technical diving for a large non-commercial (CMAS-) diving federation called the NOB in the Netherlands, Europe (50 years old, 17000 members). We are in the process of renewing/revamping our Advanced Nitrox training material & standards, and in that process we asked our Medical Committee (all doctors, amongst which the head of the Dutch Navy Dive-medical Center and a very experienced neurologist) for a view on CNS. they dug deep in old "reference" material and proof and texts, a.o. the famous NOAA CNS tables. What they came up with in short was: Scientifically speaking, there has not been much really worth-while research over the years on recreational divers for ox tox that is "convincing" or consistent. There is a lot of copy-catting in newer "research" of old findings, without additional research for verification or developed new insights. CNS% is a worthless thing. You can get into a convulsion way before 100%, or on the other hand tolerate 200%, depending on the circumstances. For that reason we will effectively drop CNS % calculations in our training material. UPTD's will stand (and are more reliable, as the research there is done in the anestaesiology area over the years, also normobaric) but are not an acute danger for the diver, so as such another matter and not of inmediate interest here. The MAJOR factor is PO2. There is no 100% guarantee in this (depending on personal susceptibility), but in general with PO2's of max. 1.4 and 1.5 your risks for convulsions are really quite low. So much so, that they dare to state that at a PO2 of 1.3 you could stay virtually limitless (i.e. exceed 100% CNS without problems). However, at or over 1.6 your risks are significant - regardless of time of exposure. Susceptibility for PO2 while diving is majorly different than above water. E.g., a standard decochamber treatment these days is 18 meter, 100%O2, which is a whopping PO2 of 2.8 bar! And convulsions do not occur really often. But don't try this while diving...... :-) So: within our federation, we will keep a max PO2 of 1.5 (normal max) or 1.4 (work, cold & training max) for exposure. This all is regardless of OC or CCR: PO2 = PO2. Hope this helps. ciao, Tino. Quote: (Originally Posted by Gobfish1) hi chris thanks for the replys ,, makes good reading . just one Q you seem to spend a good few mins on you're 70f and 60f stops are you padding them out, to make best the o2 window ,, hi ppo2 at 70f and 60f , and you're ok, hi ppo2 at last stop and you're not ok ,,, strange i must say ,,, well i hope its all in the past for you, now you;re on the ccr , stay safe m8 ps seen a few tiger sharks out in cuba, dont think i would want one as a pet ,,
(Offline)

27th August 2008, 22:14	#37 (permalink)
taza New Member Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Vision Join Date: Jul 2007 Location: Warrington UK Posts: 87	Re: How much Deco Right guys, Just got my V Planner codes & key numbers so back to playing about with different dive plans. Mod 1 air as dil Max depth 45mtr What figures shall I put in the configure dive parameters. Cheers TAZA
(Offline)

28th August 2008, 14:16	#38 (permalink)
toe RBW Member Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Oct 2006 Location: ireland Posts: 88	Re: How much Deco Quote: (Originally Posted by taza) Cheers Guys for all the info, Going over to Brets at Dive Life (Manchester UK)to look into booking MOD 1. Its going to be at least six months before I can raise the cash for the unit,Bret has offered to hire me a unit to take the course early rather than later. Cheers Colin You would be amazed how much you will forget, if you can not start diving straight after course. Would say best to wait till you are nearER getting unit. IMHO Tony
(Offline)

28th August 2008, 14:42	#39 (permalink)
nigelh New member Current Rebreather/s: Inspiration Vision Other CCR Other Rebreather/s: Inspiration Classic Other CCR Join Date: Mar 2005 Location: Brighton, Sussex, UK Posts: 883	Re: How much Deco Quote: (Originally Posted by Tino de Rijk) Susceptibility for PO2 while diving is majorly different than above water. E.g., a standard decochamber treatment these days is 18 meter, 100%O2, which is a whopping PO2 of 2.8 bar! And convulsions do not occur really often. But don't try this while diving... I have a feeling that we get convulsions because we expect convulsions. There is a strong psychological element. "Oh grief. 1.5!!! I'm gonna die!!" panic panic twitch twitch. When I started 1.6 was reasonable and 2.0 was the big no-no. In the chamber 2.8 might make you a bit trembly but they don't tell you your CNS just went over 500% so you don't get to worry. Anyway somebody else is in charge, we always like that. I have promised myself that if the ppO2 goes over the top it is dil flush and chill. That feels best. If it goes low the trick adds a breath-hold as I know I can do three minutes apnea but I must not flush more oxygen out of my body before the loop is reasonable. If I get it wrong and die get my son to post the computer dump here so you can work out where I went amiss. (My friends are under instructions to flame me retrospectively if I win a Darwin underwater.) __________________ nigelh
(Offline)

28th August 2008, 19:39	#40 (permalink)
taza New Member Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Vision Join Date: Jul 2007 Location: Warrington UK Posts: 87	Re: How much Deco Passed Mod 1 in April, done twenty dives on my baby, Just got rid of AP harness and fitted Halycon S/Steel back plate. Going out Saturday to give it a try, been walking round the garden with it on and feels much better. Still would like to know what settings to put in the configure parameters.(v planner) Cheers Taza
(Offline)

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode