Diving Hypoxic Diluent on a Normoxic Dive

***jradomski*** · 15th September 2006, 07:56

Quote: (Originally Posted by decoweenie)

Isn't that done on one of the recent Vision upgrades ?

not sure what they have done recently.. but all classics, and all the visions I have tried were NOT depth adaptive if the visions were they acted like they had no adaption at all).. they do have variable injections based on error from setpoint but as far as I know they have never taken depth into account.. adn IF AP did this, This is a major change and they would have to get the controller retested/certified since SP maintenence is part of CE testing, If they did thiis without retesting they would be breaking UK/EU law (putting a CE number on a non CE certified device).. I havent seen a new CE cert number have you?? I don't think AP would do this..

You can figure this out on your own by looking at the po2 logging, do you see bigger changes in po2 when deep?? If its truely depth adaptive, po2 injections should be even (or pretty close) across all depths..

I know they said they changed the specifics on firing times, so you really have to try and see the magnitude of the additions, not the maximal values
..

Tom Mount · 21st October 2006, 14:52

On the IANTD normoxic CCR trimix course
1. The dil po2 must be less than 1.1
2. End less than 120 ft - 36 m

The Bailout cylinder must be a normoxic one with in OW a po2 not not exceed 1.6 at MOD and in overhead 1.4 and also end no greater than 120ft- 36 m

My students typically use a 35 to 50% He thus we can use the 40% IANTD constant po2 tables (10% either side) this table is a 14 44 the oxygen is irrevealnt so mine is usually a heliar mix

Bailout is typically 20 35

So the dil in your cylinder is totally acceptable in the course

Tom Mount

Tom Mount · 21st October 2006, 14:55

Quote: (Originally Posted by vulcan)

Dave, accepted, it does. But if we accept the definition that normoxic is 21%, the depth the course certifies you to at 60m and allows you to dive to on the course takes it to 1.47ATA. The same standards say this should be no higher than 1.1ATA. Using a normoxic mix allows a maximum depth of 42m using the 1.1 ATM benchmark, nearly 20m short of what the course is training to take you to. I just took it that to acheive the 60m in training the mix Fo2 was dropped, but it still fitted the 1.1ATA standard.

Is it just a contradiction in the standards we're splitting hairs about here or am I just confused beyond comprehension

All this debate 'cause a guy asked how much gas costs would be on his Mod 2

No -no contradiction it states the max dil po2 and end

then specifies the bailout is a normoxic

Tom

Tom Mount · 21st October 2006, 14:59

Quote: (Originally Posted by vulcan)

Aint that the truth!!!

Especially as, to quote clivethediver2, his normoxix trimix cert actually says diluent of 16% o2.

I understood normoxic had to have 21% and anything less than 21% was hypoxic.

Ho hum.......

Martin
You are not breathing the Dil- it is mixed in the CCR so the normoxic applies to the bailout it DOES NOT aplly to the Dil - I hope that clears your confussion

tom

bjornaow · 21st October 2006, 15:45

Hi

On my certifacation it say 18% mixture or greater oxygen TDI OC normoxic course.

So i guess it's diffrent from organisation as always!

best regards

Björn Q

RonMicjan · 22nd October 2006, 04:45

earlier in the thread was asked how much dissolved gas is in the body, the PDIC OW student manual states that at sea level the average human body has about a quart (~liter) of dissolved nitrogen in it. So this would be saturated at sea level, continuing on, then saturated at 33fsw/10M the body should have 2 qt/lt and so on. So depending on how long at what depth, one would off gas this back into the loop during deco (CCR only, of course). I have noticed that after anO2 flush at 20fsw and hitting 1.55 PO2 or so, that eventually the PO2 falls and my voice gets squeaky again (trimix dive) and I need to do another flush to get PO2 back up and voice back to normal. I had often wondered how much gas was disolved volume wise during a dive. Now I know...

silent running · 22nd October 2006, 08:10

Quote: (Originally Posted by RonMicjan)

earlier in the thread was asked how much dissolved gas is in the body, the PDIC OW student manual states that at sea level the average human body has about a quart (~liter) of dissolved nitrogen in it. So this would be saturated at sea level, continuing on, then saturated at 33fsw/10M the body should have 2 qt/lt and so on. So depending on how long at what depth, one would off gas this back into the loop during deco (CCR only, of course). I have noticed that after anO2 flush at 20fsw and hitting 1.55 PO2 or so, that eventually the PO2 falls and my voice gets squeaky again (trimix dive) and I need to do another flush to get PO2 back up and voice back to normal. I had often wondered how much gas was disolved volume wise during a dive. Now I know...

Ron, thanks for the annecdote. I have a hard time believing that after a long, deep, dive the He off-gas is so small as to be undetectable...

Goes in faster, comes out faster and I'm not supposed to notice?

15th September 2006, 07:56	#51 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Join Date: Mar 2005 Location: "Da" Bronx Posts: 3,113	Re: Diving Hypoxic Diluent on a Normoxic Dive Quote: (Originally Posted by decoweenie) Isn't that done on one of the recent Vision upgrades ? not sure what they have done recently.. but all classics, and all the visions I have tried were NOT depth adaptive if the visions were they acted like they had no adaption at all).. they do have variable injections based on error from setpoint but as far as I know they have never taken depth into account.. adn IF AP did this, This is a major change and they would have to get the controller retested/certified since SP maintenence is part of CE testing, If they did thiis without retesting they would be breaking UK/EU law (putting a CE number on a non CE certified device).. I havent seen a new CE cert number have you?? I don't think AP would do this.. You can figure this out on your own by looking at the po2 logging, do you see bigger changes in po2 when deep?? If its truely depth adaptive, po2 injections should be even (or pretty close) across all depths.. I know they said they changed the specifics on firing times, so you really have to try and see the magnitude of the additions, not the maximal values .. __________________ 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 : 15th September 2006 at 07:58.
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21st October 2006, 14:52	#52 (permalink)
Tom Mount New Member Current Rebreather/s: Inspiration Classic Evolution Megalodon Sport Kiss Classic Kiss Optima Other CCR Other Rebreather/s: Other CCR Join Date: Jul 2005 Location: USA Posts: 95	Re: Diving Hypoxic Diluent on a Normoxic Dive On the IANTD normoxic CCR trimix course 1. The dil po2 must be less than 1.1 2. End less than 120 ft - 36 m The Bailout cylinder must be a normoxic one with in OW a po2 not not exceed 1.6 at MOD and in overhead 1.4 and also end no greater than 120ft- 36 m My students typically use a 35 to 50% He thus we can use the 40% IANTD constant po2 tables (10% either side) this table is a 14 44 the oxygen is irrevealnt so mine is usually a heliar mix Bailout is typically 20 35 So the dil in your cylinder is totally acceptable in the course Tom Mount
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21st October 2006, 14:55	#53 (permalink)
Tom Mount New Member Current Rebreather/s: Inspiration Classic Evolution Megalodon Sport Kiss Classic Kiss Optima Other CCR Other Rebreather/s: Other CCR Join Date: Jul 2005 Location: USA Posts: 95	Re: Diving Hypoxic Diluent on a Normoxic Dive Quote: (Originally Posted by vulcan) Dave, accepted, it does. But if we accept the definition that normoxic is 21%, the depth the course certifies you to at 60m and allows you to dive to on the course takes it to 1.47ATA. The same standards say this should be no higher than 1.1ATA. Using a normoxic mix allows a maximum depth of 42m using the 1.1 ATM benchmark, nearly 20m short of what the course is training to take you to. I just took it that to acheive the 60m in training the mix Fo2 was dropped, but it still fitted the 1.1ATA standard. Is it just a contradiction in the standards we're splitting hairs about here or am I just confused beyond comprehension All this debate 'cause a guy asked how much gas costs would be on his Mod 2 No -no contradiction it states the max dil po2 and end then specifies the bailout is a normoxic Tom
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21st October 2006, 14:59	#54 (permalink)
Tom Mount New Member Current Rebreather/s: Inspiration Classic Evolution Megalodon Sport Kiss Classic Kiss Optima Other CCR Other Rebreather/s: Other CCR Join Date: Jul 2005 Location: USA Posts: 95	Re: Diving Hypoxic Diluent on a Normoxic Dive Quote: (Originally Posted by vulcan) Aint that the truth!!! Especially as, to quote clivethediver2, his normoxix trimix cert actually says diluent of 16% o2. I understood normoxic had to have 21% and anything less than 21% was hypoxic. Ho hum....... Martin You are not breathing the Dil- it is mixed in the CCR so the normoxic applies to the bailout it DOES NOT aplly to the Dil - I hope that clears your confussion tom
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21st October 2006, 15:45	#55 (permalink)
bjornaow RBW Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Nov 2005 Location: SWEDEN Posts: 22	Re: Diving Hypoxic Diluent on a Normoxic Dive Hi On my certifacation it say 18% mixture or greater oxygen TDI OC normoxic course. So i guess it's diffrent from organisation as always! best regards Björn Q
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22nd October 2006, 04:45	#56 (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: 1,120	Re: Diving Hypoxic Diluent on a Normoxic Dive earlier in the thread was asked how much dissolved gas is in the body, the PDIC OW student manual states that at sea level the average human body has about a quart (~liter) of dissolved nitrogen in it. So this would be saturated at sea level, continuing on, then saturated at 33fsw/10M the body should have 2 qt/lt and so on. So depending on how long at what depth, one would off gas this back into the loop during deco (CCR only, of course). I have noticed that after anO2 flush at 20fsw and hitting 1.55 PO2 or so, that eventually the PO2 falls and my voice gets squeaky again (trimix dive) and I need to do another flush to get PO2 back up and voice back to normal. I had often wondered how much gas was disolved volume wise during a dive. Now I know... __________________ Marine rescue, towing and salvage. Interfering with natural selection since 1983. www.tmishop.com Diving bits etc. www.seatowpdx.com The Summer Job
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22nd October 2006, 08:10	#57 (permalink)
silent running Mature mouth breather Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Jun 2005 Location: U.S.A. Brooklyn, New York Posts: 1,873	Re: Diving Hypoxic Diluent on a Normoxic Dive Quote: (Originally Posted by RonMicjan) earlier in the thread was asked how much dissolved gas is in the body, the PDIC OW student manual states that at sea level the average human body has about a quart (~liter) of dissolved nitrogen in it. So this would be saturated at sea level, continuing on, then saturated at 33fsw/10M the body should have 2 qt/lt and so on. So depending on how long at what depth, one would off gas this back into the loop during deco (CCR only, of course). I have noticed that after anO2 flush at 20fsw and hitting 1.55 PO2 or so, that eventually the PO2 falls and my voice gets squeaky again (trimix dive) and I need to do another flush to get PO2 back up and voice back to normal. I had often wondered how much gas was disolved volume wise during a dive. Now I know... Ron, thanks for the annecdote. I have a hard time believing that after a long, deep, dive the He off-gas is so small as to be undetectable... Goes in faster, comes out faster and I'm not supposed to notice?
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