Gas Break info?

sannerman · 11th November 2006, 06:49

Hi all you guys and gals out there,

I´m trying to find some information about gas breaks, but it seems to bee hard to find. So if any one have links or other information to share here would be really appreciated.

And how many of you are using those breaks, and if, what criteria are you using to apply breaks in the deco profile

/Z

jhaaja · 11th November 2006, 07:17

On OC I used to do 12mins O2 then 5mins of back gas. On ccr I use the same system if I have more than 20mins to hang at 6m. I just drop the setpoint to 0,7 for 5mins.

Mostly I do it because my instructor told me so

Also it helps to keep the CNS% a little lower and it has been proved in practice that it seems to work.

If the 6m hang is not long I don't bother to fiddle with the setpoint.

When are you coming to the other side of our own sea? I might have some nice cave diving for you...

jptaylor9 · 11th November 2006, 08:18

Quote: (Originally Posted by jhaaja)

On ccr I use the same system if I have more than 20mins to hang at 6m. I just drop the setpoint to 0,7 for 5mins.

Mostly I do it because my instructor told me so

Just out of interest, do you dil flush when you drop the setpoint for 5 mins to drop the ppO2?

If yes, isn't this wastefull on gas, both O2 & dil?

jhaaja · 11th November 2006, 14:00

Quote: (Originally Posted by jptaylor9)

Just out of interest, do you dil flush when you drop the setpoint for 5 mins to drop the ppO2?

If yes, isn't this wastefull on gas, both O2 & dil?

Basically I flush. Exhale through nose and inhale dil from ADV. It does not take many liters of gas since I am at 6m depth.

If I want I can also take gas from bail stage that is plugged to the BOV.

sannerman · 11th November 2006, 14:30

Quote: (Originally Posted by jhaaja)

On OC I used to do 12mins O2 then 5mins of back gas. On ccr I use the same system if I have more than 20mins to hang at 6m. I just drop the setpoint to 0,7 for 5mins.

So when you calculate your deco tables you have for example 40 min at 6m. Do you just do the 40 min with the gas break included, or do you add time to "compensate" for "lost" deco time on low PO2? Or just count the 40 min as on 100% O2?

/Z

***Decodiver*** · 11th November 2006, 20:36

Sannerman,

After 180 min RT, low PO2 break on OC for 5 mins after every 20 mins on the loop.

Reducing the setpoint to 0.7 and doing this on the loop is a complete waste of time.

Jhaaja, I suggest you ask your instructor to quantify why he suggests doing this on the loop.

Cheers,

Dave Cooper.

sannerman · 12th November 2006, 07:34

Quote: (Originally Posted by Decodiver)

Sannerman,

After 180 min RT, low PO2 break on OC for 5 mins after every 20 mins on the loop.

Reducing the setpoint to 0.7 and doing this on the loop is a complete waste of time.

Jhaaja, I suggest you ask your instructor to quantify why he suggests doing this on the loop.

Cheers,

Dave Cooper.

Hi Dave,

Some more question from me:

"After 180 min RT, low PO2 break on OC for 5 mins after every 20 mins on the loop."
Why 180min, and what set point have you dived on then? or do you have a certain CNS% level you start with gas breaks? Why must it be on OC and not on the loop?

"Reducing the set point to 0.7 and doing this on the loop is a complete waste of time."
Why is it a waste of time, because it´s on the loop or to low set point?

I´m trying to figure out what people are using fore determine when to add gas breaks.

And any one here have any "hard facts" regarding gasbreaks, like articles or recommendation of what book to read more about this?

/Z

James · 12th November 2006, 08:57

Quote: (Originally Posted by sannerman)

Hi Dave,

Some more question from me:

"After 180 min RT, low PO2 break on OC for 5 mins after every 20 mins on the loop."

/Z

It's certainly easier to eat and drink on OC, which you should be doing a little of on run times of this length.

Generally I'm absoulutly starving by the 90min mark!

James.

Depth-junkie · 12th November 2006, 10:08

Quote:

Some more question from me:

"After 180 min RT, low PO2 break on OC for 5 mins after every 20 mins on the loop."
Why 180min, and what set point have you dived on then? or do you have a certain CNS% level you start with gas breaks? Why must it be on OC and not on the loop?

"Reducing the set point to 0.7 and doing this on the loop is a complete waste of time."
Why is it a waste of time, because it´s on the loop or to low set point?

At 180min running a SP1.3 you reach the 100% CNS limit (0.56% per min), hence the time for airbreaks.

The reason not to use a low SP of 0.70 is because you will still be breathing 43% O2 @ 6m, not a low enough fraction of O2. Hence the reason to go OC on a bottom gas mix I.E 15/50 or a 18/40.

Hope this helps

ATB
Gareth

Hope this helps

Gobfish1 · 12th November 2006, 10:40

Quote: (Originally Posted by Depth-junkie)

At 180min running a SP1.3 you reach the 100% CNS limit (0.56% per min), hence the time for airbreaks.

The reason not to use a low SP of 0.70 is because you will still be breathing 43% O2 @ 6m, not a low enough fraction of O2. Hence the reason to go OC on a bottom gas mix I.E 15/50 or a 18/40.

Hope this helps

ATB
Gareth

Hope this helps

thanks Gaz

11th November 2006, 06:49	#1 (permalink)
sannerman Let´s Go Down For a While Current Rebreather/s: Classic Kiss MK 15.X Other CCR Other Rebreather/s: Other CCR Join Date: Apr 2005 Location: Sweden Posts: 95	Gas Break info? Hi all you guys and gals out there, I´m trying to find some information about gas breaks, but it seems to bee hard to find. So if any one have links or other information to share here would be really appreciated. And how many of you are using those breaks, and if, what criteria are you using to apply breaks in the deco profile /Z __________________ Det är hårt på sjön, fast hårdare på land www.pagi.se
(Online)

11th November 2006, 07:17	#2 (permalink)
jhaaja Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Mar 2005 Location: Finland Posts: 883	Re: Gas Break info? On OC I used to do 12mins O2 then 5mins of back gas. On ccr I use the same system if I have more than 20mins to hang at 6m. I just drop the setpoint to 0,7 for 5mins. Mostly I do it because my instructor told me so Also it helps to keep the CNS% a little lower and it has been proved in practice that it seems to work. If the 6m hang is not long I don't bother to fiddle with the setpoint. When are you coming to the other side of our own sea? I might have some nice cave diving for you...
(Offline)

11th November 2006, 08:18	#3 (permalink)
jptaylor9 Member Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: London, UK Posts: 312	Re: Gas Break info? Quote: (Originally Posted by jhaaja) On ccr I use the same system if I have more than 20mins to hang at 6m. I just drop the setpoint to 0,7 for 5mins. Mostly I do it because my instructor told me so Just out of interest, do you dil flush when you drop the setpoint for 5 mins to drop the ppO2? If yes, isn't this wastefull on gas, both O2 & dil?
(Offline)

11th November 2006, 14:00	#4 (permalink)
jhaaja Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Mar 2005 Location: Finland Posts: 883	Re: Gas Break info? Quote: (Originally Posted by jptaylor9) Just out of interest, do you dil flush when you drop the setpoint for 5 mins to drop the ppO2? If yes, isn't this wastefull on gas, both O2 & dil? Basically I flush. Exhale through nose and inhale dil from ADV. It does not take many liters of gas since I am at 6m depth. If I want I can also take gas from bail stage that is plugged to the BOV.
(Offline)

11th November 2006, 14:30	#5 (permalink)
sannerman Let´s Go Down For a While Current Rebreather/s: Classic Kiss MK 15.X Other CCR Other Rebreather/s: Other CCR Join Date: Apr 2005 Location: Sweden Posts: 95	Re: Gas Break info? Quote: (Originally Posted by jhaaja) On OC I used to do 12mins O2 then 5mins of back gas. On ccr I use the same system if I have more than 20mins to hang at 6m. I just drop the setpoint to 0,7 for 5mins. So when you calculate your deco tables you have for example 40 min at 6m. Do you just do the 40 min with the gas break included, or do you add time to "compensate" for "lost" deco time on low PO2? Or just count the 40 min as on 100% O2? /Z __________________ Det är hårt på sjön, fast hårdare på land www.pagi.se
(Online)

11th November 2006, 20:36	#6 (permalink)
*Decodiver* Administrator Current Rebreather/s: Megalodon Ouroboros rEvo Other CCR Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Sport Kiss Classic Kiss rEvo Other CCR Join Date: Jan 2005 Location: Geneva Posts: 2,178	Re: Gas Break info? Sannerman, After 180 min RT, low PO2 break on OC for 5 mins after every 20 mins on the loop. Reducing the setpoint to 0.7 and doing this on the loop is a complete waste of time. Jhaaja, I suggest you ask your instructor to quantify why he suggests doing this on the loop. Cheers, Dave Cooper. __________________ CCR/OC Trimix Instructor Trainer CCR Training to Mixed Gas in Switzerland, France, UK & Germany on Megalodon/COPIS-Megalodon/KISS/Sport KISS/Ouroboros/rEvo/Inspiration/Evolution/Sentinel www.zerogravitydiving.com Rebreather World Terms & Conditions
(Offline)

12th November 2006, 07:34	#7 (permalink)
sannerman Let´s Go Down For a While Current Rebreather/s: Classic Kiss MK 15.X Other CCR Other Rebreather/s: Other CCR Join Date: Apr 2005 Location: Sweden Posts: 95	Re: Gas Break info? Quote: (Originally Posted by Decodiver) Sannerman, After 180 min RT, low PO2 break on OC for 5 mins after every 20 mins on the loop. Reducing the setpoint to 0.7 and doing this on the loop is a complete waste of time. Jhaaja, I suggest you ask your instructor to quantify why he suggests doing this on the loop. Cheers, Dave Cooper. Hi Dave, Some more question from me: "After 180 min RT, low PO2 break on OC for 5 mins after every 20 mins on the loop." Why 180min, and what set point have you dived on then? or do you have a certain CNS% level you start with gas breaks? Why must it be on OC and not on the loop? "Reducing the set point to 0.7 and doing this on the loop is a complete waste of time." Why is it a waste of time, because it´s on the loop or to low set point? I´m trying to figure out what people are using fore determine when to add gas breaks. And any one here have any "hard facts" regarding gasbreaks, like articles or recommendation of what book to read more about this? /Z __________________ Det är hårt på sjön, fast hårdare på land www.pagi.se
(Online)

12th November 2006, 08:57	#8 (permalink)
James New Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: May 2005 Location: UK Posts: 59	Re: Gas Break info? Quote: (Originally Posted by sannerman) Hi Dave, Some more question from me: "After 180 min RT, low PO2 break on OC for 5 mins after every 20 mins on the loop." /Z It's certainly easier to eat and drink on OC, which you should be doing a little of on run times of this length. Generally I'm absoulutly starving by the 90min mark! James.
(Offline)

12th November 2006, 10:08	#9 (permalink)
Depth-junkie 10/52 Psycho Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Aug 2005 Location: Wrexham Posts: 291	Re: Gas Break info? Quote: Some more question from me: "After 180 min RT, low PO2 break on OC for 5 mins after every 20 mins on the loop." Why 180min, and what set point have you dived on then? or do you have a certain CNS% level you start with gas breaks? Why must it be on OC and not on the loop? "Reducing the set point to 0.7 and doing this on the loop is a complete waste of time." Why is it a waste of time, because it´s on the loop or to low set point? At 180min running a SP1.3 you reach the 100% CNS limit (0.56% per min), hence the time for airbreaks. The reason not to use a low SP of 0.70 is because you will still be breathing 43% O2 @ 6m, not a low enough fraction of O2. Hence the reason to go OC on a bottom gas mix I.E 15/50 or a 18/40. Hope this helps ATB Gareth Hope this helps
(Offline)

12th November 2006, 10:40	#10 (permalink)
Gobfish1 Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Join Date: Apr 2005 Location: Manchester UK Posts: 361	Re: Gas Break info? Quote: (Originally Posted by Depth-junkie) At 180min running a SP1.3 you reach the 100% CNS limit (0.56% per min), hence the time for airbreaks. The reason not to use a low SP of 0.70 is because you will still be breathing 43% O2 @ 6m, not a low enough fraction of O2. Hence the reason to go OC on a bottom gas mix I.E 15/50 or a 18/40. Hope this helps ATB Gareth Hope this helps thanks Gaz
(Offline)

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