O2 slug

OceanOpportunity · 30th April 2008, 20:07

discussions like this are always informative. It brings me to a train of thought from the design/mfg perspective however. That being, was there a specific reason that the O2 button was put on the inhale lung...or alternatively, it ended up on the inhale lung and a valid reason for it was found later?

What I do like about the Meg is the intuitive loop direction (inhale over right, exhale over left). If this were the primary design intention, and a rich on right/lean on left mantra was sought after, then the O2 button could've 'ended up' there. I'd be interested in comments from ISC on this.

I'm not saying its a bad way of going about things, as I can appreciate that many, if not all, of the units out there were developed very. very early in the game and there wasn't enough insight, data, or practical field time out there to validate a number of the designs. Consider how long they've been around, and just now (within a year/two) this design is questioned!

fin · 30th April 2008, 21:16

Very enlightening thread! Most ideas have good basis.

I want to share an idea that seems to get the best from both worlds for a COPIS owner (at least).
Why not use standard (not compensated) O2 reg feeding the ISC way the inhale cl and at the same time the second compensated O2 reg (must for deeper dives) connected to exhale cl?
Please don't hesitate to shoot

if its a joke

jkaterenchuk · 30th April 2008, 21:33

Quote: (Originally Posted by OceanOpportunity)

discussions like this are always informative. It brings me to a train of thought from the design/mfg perspective however. That being, was there a specific reason that the O2 button was put on the inhale lung...or alternatively, it ended up on the inhale lung and a valid reason for it was found later?

Michael

See earlier in the thread. You might have missed it but I posted the email response as to the reason direct from ISC.

John

**wedivebc** · 30th April 2008, 23:37

Quote: (Originally Posted by fin)

Very enlightening thread! Most ideas have good basis.

I want to share an idea that seems to get the best from both worlds for a COPIS owner (at least).
Why not use standard (not compensated) O2 reg feeding the ISC way the inhale cl and at the same time the second compensated O2 reg (must for deeper dives) connected to exhale cl?
Please don't hesitate to shoot

if its a joke

I think that makes lots of sense for a copis diver. Stage some O2 for bailout and feed some into the O2 byopass for the deeper excurion of the dive using a non compensated 1st.

Parker · 1st May 2008, 11:56

Quote: (Originally Posted by OceanOpportunity)

discussions like this are always informative. It brings me to a train of thought from the design/mfg perspective however. That being, was there a specific reason that the O2 button was put on the inhale lung...or alternatively, it ended up on the inhale lung and a valid reason for it was found later?

What I do like about the Meg is the intuitive loop direction (inhale over right, exhale over left). If this were the primary design intention, and a rich on right/lean on left mantra was sought after, then the O2 button could've 'ended up' there. I'd be interested in comments from ISC on this.

I think that Jerry @ ISC has made it pretty clear why manual O2 injection is intended for the inhale (right) CL on the Meg. His words are around here somewhere and shouldn't be too hard to find. There is an injection valve on the exhale (left) CL that sits just below the ADV and looks just like the one on the inhale (right) CL. Now, some of us, depending on our needs and style of diving, looked at those two identical injection valves and said- hey buddy, hold my beer!

I'm gonna switch these hoses and see if it makes things any better. And some, like myself, found that injecting O2 into the exhale (left) CL makes a lot of since, especially when it comes to scootering in an overhead environment, managing a light, injecting gases, etc, etc... The O2 response time on the handset/HUD is a bit quicker when injecting on the exhale CL and it's the only way to go when doing a O2 flush on the loop. You don't have to squeeze the hose or anything. Just breath out, O2 flush, breath in, and repeat as necessary. The only real downside is it might take a little longer for the O2 to reach the divers lips in a hypoxic situation. But how often does this really happen? And if it does happen a lot- WHY? Who's not monitoring their handset/HUD? Even on a rapid ascent- one should know their target PO2 if nothing changes regarding O2/Dil injection.

If you think that you might like to experience the advantages of injecting O2 on the exhale (left) CL then give it a go. If not, and injecting on the inhale (right) CL makes more since- then there you go- stick with that!

We can all be happy

with our choice as long as there is sound reasoning behind it and it meets our needs, not just occasionally- but every time we dive the configuration.
Hope this helps!

Parker

Lancer4545 · 1st May 2008, 12:14

Quote: (Originally Posted by gtzavelas)

Interesting discussion, as everything in life you have to balance the pros/cons of the 2 alternatives.
I will try to detail my thinking about the 2 risks discussed:

RISK A: Hypoxia
possibility: extremely low , must arrive to 0,16 from the 1, 1 I usually use. I must really mess up as monitoring my PO2 is usually number priority #1
action : turn your BOV to OC (preferred for me , take 2-3 breaths from BOV and deal with the problem at the same time)or inject diluent (not so good) or inject O2 (this will have a slower response if plugged at the exhalation )
So moving the O2 to the exhalation lung will slow the response time of 1 of the 3 solutions to resolve a low PO2 situation

RISK B: Hyperoxia
Manual addition button sticking ON at great depth [ or alternatively much less risk to eject more O2 than planned by pressing the O2 addition longer (again at great depth)]
Possibility: low but out of control of diver (the manual button sticking ON)
Action: if O2 is stuck ON, remove O2 hose (or close O2 tank) and at the same time bail out or flash with diluent. Task loading will be very high as buoyancy will change fast and diver becomes buoyant
By plugging O2 to exhalation you minimize risk of Hyperoxia
risk B seems to me to be higher and because of high task loading seems worse

so by plugging the O2 to exhalation you mizimize the worst of the two risks

To say that the risk of Hypoxia is extremely low is VERY WRONG. If you look at the majority of rebreather incidents it's very clear the most dangerous part of the dive is at or near the surface and from Hypoxia......

There are a few different options to fix the situation if you're able.........But that's where the trouble seems to be. You're here one minute and off in noddy land the next........Dropped the DSV or BOV had a big drink and flooded your unit and on the express elevator.....DOWN!!!

There have been many arguments about stuck manual addition valves but when you hit the button and it sticks on you DO HAVE TIME to fix the situation and you have the ability to fix it. The manual addition valves don't allow a high flow rate like the ADV. Just how long will it take for you to disconnect the hose and stop the flow.......Not very long if you have been practicing and know your way around your unit. Then flush the loop and swap the hose to the other valve......Not really a big deal!!!

And don't forget if you change the hose to the exhale CL there is the issue with accidentally firing the ADV.

Knowing the buttons are in the std configuration is a big help if someone has to rescue you and they can go straight to the right one and activate it.......more so when every second could make a big difference to the outcome.....

Regards,

Lance

mempilot · 1st May 2008, 14:36

Lance,

You are spot on.

IMHO, hypoxia is the more dangerous situation. I've experienced it in the altitude chambers, and it wasn't until watching the video of the event afterwards that I realized how f'd up I was and unable to do the simplest tasks.

This is why I use the ADV for a @1.0 PO2 DIL flush at max depth. Breathing out while hammering the ADV and crossing the left arm over the CL's will push a lot of gas through the loop in an instant. Hammering DIL, even if not needed, will not kill you.

The only time I use O2 manual injection is for flying manually for practice, finite bouyancy control in shallow water, 6m O2 flush, or after a solenoid failure. Like Lance, I believe there is plenty of time to deal with high PO2, such as the possible solenoid stuck on or manual gas bypass stuck on. These two problems are real obvious and very easy to deal with in a calm manner. Remember OC days? Roll the offending post off, right? Or, even easier if it's the MGBP valve: Remember the stuck drysuit inflation valve drill? Pop the hose off the valve for an immediate bandaid.

Hyperoxic is a matter of dose and time. Hypoxia is a matter of just a few breaths. So unless one is conducting dives at up around 1.6 PO2 for very long periods of time, a spike above that can be tolerable while one deals with the situation prior to experiencing hyperoxic tox symptoms.

As for handset and HUD monitoring: Absolutely important for all of this. "Know your PO2". And if we do all this right, hypoxia would be a huge mistake and so hyperoxia would be as well. So one has to look at the possible failures that could cause these problems and the solutions to them.

Rebreather failures that impact PO2 are fairly easy to deal with if practiced and understood. Diver failures are usually the cause of hypoxia, and can be very difficult to deal with in the mental state the condition leaves you in. It can also be like walking off a cliff. One breath you are fine. The next breath you are incapicitated. I like having the ADV and known end result PO2 of using it to immediately put breathable gas into the loop. I also put a DIL PO2 chart on my primary handset for doing these flushes at less than max depth for cell validation. Using the O2 injection to solve hypoxia gives you an unknown gas until the cells can analyze it. Not good if you didn't put in enough or too much. I like instantaneous results in a potential hypoxic situation.

Sorry for the long post. It's a bit of reduction from a previous post of mine in this thread.

**Fun Under Pressure** · 1st May 2008, 18:19

For me a oxtox is a result of pressure and time. When i do 1 or 2 breathes of 100% O2 in a deep of 70 meters so must i do this from my bailout stage and i think that do nothing with me. When i do this from my cl the cl must been complete empty and my WOB must increase. So i do an O2 flush in a lightly filled cl and do not breath pure O2. As Lancer said, for me it is a training scill to disconnect/connect the O2 hose and disconnect/connect the hoses from my bailout tanks to my MGBP. I am new on the Meg but this is my opinion.

30th April 2008, 20:07	#31 (permalink)
OceanOpportunity for a world of water Current Rebreather/s: Other CCR Dolphin Home Build Other Rebreather/s: Not Bought Yet Inspiration Classic Other CCR Dolphin Home Build Join Date: Nov 2006 Location: Providence, RI USA Posts: 447	Re: O2 slug discussions like this are always informative. It brings me to a train of thought from the design/mfg perspective however. That being, was there a specific reason that the O2 button was put on the inhale lung...or alternatively, it ended up on the inhale lung and a valid reason for it was found later? What I do like about the Meg is the intuitive loop direction (inhale over right, exhale over left). If this were the primary design intention, and a rich on right/lean on left mantra was sought after, then the O2 button could've 'ended up' there. I'd be interested in comments from ISC on this. I'm not saying its a bad way of going about things, as I can appreciate that many, if not all, of the units out there were developed very. very early in the game and there wasn't enough insight, data, or practical field time out there to validate a number of the designs. Consider how long they've been around, and just now (within a year/two) this design is questioned! __________________ Michael Lombardi Oceans of Opportunity www.oceanopportunity.com Gear Reviewer, The Summit Journal exploration & scientific diving resources www.explorationtechnologiesgroup.com
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30th April 2008, 21:16	#32 (permalink)
fin New Member Current Rebreather/s: Megalodon Dolphin Other Rebreather/s: Megalodon Dolphin Join Date: Jul 2006 Location: Thessaloniki, Hellas (Greece) Posts: 44	Re: O2 slug Very enlightening thread! Most ideas have good basis. I want to share an idea that seems to get the best from both worlds for a COPIS owner (at least). Why not use standard (not compensated) O2 reg feeding the ISC way the inhale cl and at the same time the second compensated O2 reg (must for deeper dives) connected to exhale cl? Please don't hesitate to shoot if its a joke
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30th April 2008, 21:33	#33 (permalink)
jkaterenchuk . Current Rebreather/s: Inspiration Classic Megalodon Classic Kiss Other Rebreather/s: Join Date: May 2006 Location: Lititz, PA Posts: 395	Re: O2 slug Quote: (Originally Posted by OceanOpportunity) discussions like this are always informative. It brings me to a train of thought from the design/mfg perspective however. That being, was there a specific reason that the O2 button was put on the inhale lung...or alternatively, it ended up on the inhale lung and a valid reason for it was found later? Michael See earlier in the thread. You might have missed it but I posted the email response as to the reason direct from ISC. John
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30th April 2008, 23:37	#34 (permalink)
wedivebc FIGJAM Current Rebreather/s: Megalodon Other CCR Other Rebreather/s: Not Bought Yet Inspiration Classic Sport Kiss Other CCR Join Date: Feb 2005 Location: Vancouver Island BC Canada Posts: 1,273	Re: O2 slug Quote: (Originally Posted by fin) Very enlightening thread! Most ideas have good basis. I want to share an idea that seems to get the best from both worlds for a COPIS owner (at least). Why not use standard (not compensated) O2 reg feeding the ISC way the inhale cl and at the same time the second compensated O2 reg (must for deeper dives) connected to exhale cl? Please don't hesitate to shoot if its a joke I think that makes lots of sense for a copis diver. Stage some O2 for bailout and feed some into the O2 byopass for the deeper excurion of the dive using a non compensated 1st. __________________ Cheers, Dave.... Man is the only animal burdened with the knowledge he will eventually die
(Online)

1st May 2008, 11:56	#35 (permalink)
Parker what bubbles? Current Rebreather/s: Megalodon Dolphin Home Build Other Rebreather/s: Dolphin Home Build Join Date: Jun 2007 Location: USA Posts: 59	Re: O2 slug Quote: (Originally Posted by OceanOpportunity) discussions like this are always informative. It brings me to a train of thought from the design/mfg perspective however. That being, was there a specific reason that the O2 button was put on the inhale lung...or alternatively, it ended up on the inhale lung and a valid reason for it was found later? What I do like about the Meg is the intuitive loop direction (inhale over right, exhale over left). If this were the primary design intention, and a rich on right/lean on left mantra was sought after, then the O2 button could've 'ended up' there. I'd be interested in comments from ISC on this. I think that Jerry @ ISC has made it pretty clear why manual O2 injection is intended for the inhale (right) CL on the Meg. His words are around here somewhere and shouldn't be too hard to find. There is an injection valve on the exhale (left) CL that sits just below the ADV and looks just like the one on the inhale (right) CL. Now, some of us, depending on our needs and style of diving, looked at those two identical injection valves and said- hey buddy, hold my beer! I'm gonna switch these hoses and see if it makes things any better. And some, like myself, found that injecting O2 into the exhale (left) CL makes a lot of since, especially when it comes to scootering in an overhead environment, managing a light, injecting gases, etc, etc... The O2 response time on the handset/HUD is a bit quicker when injecting on the exhale CL and it's the only way to go when doing a O2 flush on the loop. You don't have to squeeze the hose or anything. Just breath out, O2 flush, breath in, and repeat as necessary. The only real downside is it might take a little longer for the O2 to reach the divers lips in a hypoxic situation. But how often does this really happen? And if it does happen a lot- WHY? Who's not monitoring their handset/HUD? Even on a rapid ascent- one should know their target PO2 if nothing changes regarding O2/Dil injection. If you think that you might like to experience the advantages of injecting O2 on the exhale (left) CL then give it a go. If not, and injecting on the inhale (right) CL makes more since- then there you go- stick with that! We can all be happy with our choice as long as there is sound reasoning behind it and it meets our needs, not just occasionally- but every time we dive the configuration. Hope this helps! Parker
(Online)

1st May 2008, 12:14	#36 (permalink)
Lancer4545 Closed Circuit Divers Aus Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Jun 2007 Location: Cairns QLD Australia Posts: 460	Re: O2 slug Quote: (Originally Posted by gtzavelas) Interesting discussion, as everything in life you have to balance the pros/cons of the 2 alternatives. I will try to detail my thinking about the 2 risks discussed: RISK A: Hypoxia possibility: extremely low , must arrive to 0,16 from the 1, 1 I usually use. I must really mess up as monitoring my PO2 is usually number priority #1 action : turn your BOV to OC (preferred for me , take 2-3 breaths from BOV and deal with the problem at the same time)or inject diluent (not so good) or inject O2 (this will have a slower response if plugged at the exhalation ) So moving the O2 to the exhalation lung will slow the response time of 1 of the 3 solutions to resolve a low PO2 situation RISK B: Hyperoxia Manual addition button sticking ON at great depth [ or alternatively much less risk to eject more O2 than planned by pressing the O2 addition longer (again at great depth)] Possibility: low but out of control of diver (the manual button sticking ON) Action: if O2 is stuck ON, remove O2 hose (or close O2 tank) and at the same time bail out or flash with diluent. Task loading will be very high as buoyancy will change fast and diver becomes buoyant By plugging O2 to exhalation you minimize risk of Hyperoxia risk B seems to me to be higher and because of high task loading seems worse so by plugging the O2 to exhalation you mizimize the worst of the two risks To say that the risk of Hypoxia is extremely low is VERY WRONG. If you look at the majority of rebreather incidents it's very clear the most dangerous part of the dive is at or near the surface and from Hypoxia...... There are a few different options to fix the situation if you're able.........But that's where the trouble seems to be. You're here one minute and off in noddy land the next........Dropped the DSV or BOV had a big drink and flooded your unit and on the express elevator.....DOWN!!! There have been many arguments about stuck manual addition valves but when you hit the button and it sticks on you DO HAVE TIME to fix the situation and you have the ability to fix it. The manual addition valves don't allow a high flow rate like the ADV. Just how long will it take for you to disconnect the hose and stop the flow.......Not very long if you have been practicing and know your way around your unit. Then flush the loop and swap the hose to the other valve......Not really a big deal!!! And don't forget if you change the hose to the exhale CL there is the issue with accidentally firing the ADV. Knowing the buttons are in the std configuration is a big help if someone has to rescue you and they can go straight to the right one and activate it.......more so when every second could make a big difference to the outcome..... Regards, Lance __________________ You can run but you can't hide! http://www.closedcircuitdivers.com.au info@closedcircuitdivers.com.au
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1st May 2008, 14:36	#37 (permalink)
mempilot What is this..terrafirma? Current Rebreather/s: Megalodon Other Rebreather/s: Megalodon Join Date: Aug 2006 Location: Ft. Lauderdale Posts: 810	Re: O2 slug Lance, You are spot on. IMHO, hypoxia is the more dangerous situation. I've experienced it in the altitude chambers, and it wasn't until watching the video of the event afterwards that I realized how f'd up I was and unable to do the simplest tasks. This is why I use the ADV for a @1.0 PO2 DIL flush at max depth. Breathing out while hammering the ADV and crossing the left arm over the CL's will push a lot of gas through the loop in an instant. Hammering DIL, even if not needed, will not kill you. The only time I use O2 manual injection is for flying manually for practice, finite bouyancy control in shallow water, 6m O2 flush, or after a solenoid failure. Like Lance, I believe there is plenty of time to deal with high PO2, such as the possible solenoid stuck on or manual gas bypass stuck on. These two problems are real obvious and very easy to deal with in a calm manner. Remember OC days? Roll the offending post off, right? Or, even easier if it's the MGBP valve: Remember the stuck drysuit inflation valve drill? Pop the hose off the valve for an immediate bandaid. Hyperoxic is a matter of dose and time. Hypoxia is a matter of just a few breaths. So unless one is conducting dives at up around 1.6 PO2 for very long periods of time, a spike above that can be tolerable while one deals with the situation prior to experiencing hyperoxic tox symptoms. As for handset and HUD monitoring: Absolutely important for all of this. "Know your PO2". And if we do all this right, hypoxia would be a huge mistake and so hyperoxia would be as well. So one has to look at the possible failures that could cause these problems and the solutions to them. Rebreather failures that impact PO2 are fairly easy to deal with if practiced and understood. Diver failures are usually the cause of hypoxia, and can be very difficult to deal with in the mental state the condition leaves you in. It can also be like walking off a cliff. One breath you are fine. The next breath you are incapicitated. I like having the ADV and known end result PO2 of using it to immediately put breathable gas into the loop. I also put a DIL PO2 chart on my primary handset for doing these flushes at less than max depth for cell validation. Using the O2 injection to solve hypoxia gives you an unknown gas until the cells can analyze it. Not good if you didn't put in enough or too much. I like instantaneous results in a potential hypoxic situation. Sorry for the long post. It's a bit of reduction from a previous post of mine in this thread. __________________ MEM "Da Pilot" Black holes are where God divided by zero. "If at first you don't succeed, don't dive silent." "Would you mind not shooting at the thermo-nuclear weapons." ~ Vic Deakins "Donkey's kill more people annually than plane crashes."
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1st May 2008, 18:19	#38 (permalink)
Fun Under Pressure Supporting Member Current Rebreather/s: Megalodon Other Rebreather/s: Inspiration Classic Join Date: Nov 2006 Location: Germany Posts: 520	Re: O2 slug For me a oxtox is a result of pressure and time. When i do 1 or 2 breathes of 100% O2 in a deep of 70 meters so must i do this from my bailout stage and i think that do nothing with me. When i do this from my cl the cl must been complete empty and my WOB must increase. So i do an O2 flush in a lightly filled cl and do not breath pure O2. As Lancer said, for me it is a training scill to disconnect/connect the O2 hose and disconnect/connect the hoses from my bailout tanks to my MGBP. I am new on the Meg but this is my opinion. __________________ Cheers Markku Meg # 773 "DIR is the nanny state for divers who cannot think on their own" Ron Micjan
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