Functionaing with only 92% O2

Mark Chase · 13th October 2007, 03:56

[quote]

Quote: (Originally Posted by Gilles)

That is key

This works in practise

, providing you don't lose a cell and need to change. Your holiday is jeopardised by not being able to set your cal-gas purity.

This is the big down fall on ECCRs. On my KISS id just whack in a new cell and put up with what ever reading it gave me. If i know cell 2 is 0.2 out I can handle it and not miss a dive.

Quote:

Not without putting your life in grave jeopardy. If your cells become worn, they will tend to output less mV than needed to provide you a correct PO2 readout.

Again i struggle to make sense of this.

I would have thaught you can calibrate a cell in any gas with 02 in?

If you calibrated it in 10/52 its still calibrated. Surley all you need to do then is confirm with what ever your diving on at the 6m stop or deeper.

As an example why not calibrate in air, then drop to 6m on your (lets say 80%) Your cells should read 1.28. Drop to 12m and they should say 1.76

So you have confirmed the cells are not current limited and you have confirmed the calibration.

I cant see a problem with this?

ATB

Mark

JS1scuba · 13th October 2007, 04:35

Quote: (Originally Posted by Mixaddict)

I did a week on my inspo on the Oddyssey a couple of years ago. I was getting about 94%. Did the entire week without any side effects. Obviously, I'm not suggesting that it will work for you, but I just adjusted my inspo to match what my gas analysis gave me. I don't know if that was the right thing to do or not, but it worked for me. The biggest issue for me, was that I tend to get narked a little easier on CCR than I do on OC. (Don't reall know why, but I suspect it has to do with the task loading.) Unfortunately, they don't have any helium on the boat when you are doing the really deep stuff like the San Fransisco Maru etc.

Randy, the narc'd thing is something to look at. If you are running your PO2 high you may be experiencing minor effects of ox tox (many of the signs and symptoms are similar to nitrogen narcosis). You mention task loading. Not really sure why you think CCR is more task loaded than OC diving. You may also be getting some breakthrough and getting some minor CO2 issues.

Try to get a better handle on that one the next time you go out.

Cheers

JDS

Mark Chase · 13th October 2007, 05:11

Quote: (Originally Posted by JS1scuba)

Randy, the narc'd thing is something to look at. If you are running your PO2 high you may be experiencing minor effects of ox tox (many of the signs and symptoms are similar to nitrogen narcosis). You mention task loading. Not really sure why you think CCR is more task loaded than OC diving. You may also be getting some breakthrough and getting some minor CO2 issues.

Try to get a better handle on that one the next time you go out.

Cheers

JDS

I didnt know there was such a thing as a minor 02 tox? (appart from lung iritation) What sort of symptoms do you mean?

ATB

Mark

Gilles · 13th October 2007, 05:11

[quote=Mark Chase;143172]

Quote:

This is the big down fall on ECCRs. On my KISS id just whack in a new cell and put up with what ever reading it gave me. If i know cell 2 is 0.2 out I can handle it and not miss a dive.

Again i struggle to make sense of this.

I would have thaught you can calibrate a cell in any gas with 02 in?

If you calibrated it in 10/52 its still calibrated. Surley all you need to do then is confirm with what ever your diving on at the 6m stop or deeper.

As an example why not calibrate in air, then drop to 6m on your (lets say 80%) Your cells should read 1.28. Drop to 12m and they should say 1.76

So you have confirmed the cells are not current limited and you have confirmed the calibration.

I cant see a problem with this?

ATB

Mark

On your 1st point, certain eCCR makes (that I'm familiar with

) allow you to set the cal-gas purity (down to 80%) before calibrating.

Above you describe an in-water cell check. This is ok if they check ok, but what if they do not check ok? There's no means to set the low and high PO2 cal points if the nominal voltage of your new cells is different from the one that you're changing.

Your still stuck with a substantial risk of ruining your trip. It's possible that you have the same problem with mCCR (I'm guessing on that one).

Mark Chase · 13th October 2007, 05:35

[quote][quote=Gilles;143178]

Quote: (Originally Posted by Mark Chase)

On your 1st point, certain eCCR makes (that I'm familiar with

) allow you to set the cal-gas purity (down to 80%) before calibrating.

Sure, i had an Inspo that would do that.

Quote:

Above you describe an in-water cell check. This is ok if they check ok, but what if they do not check ok? There's no means to set the low and high PO2 cal points if the nominal voltage of your new cells is different from the one that you're changing.

If they dont check OK then they are faulty and should be compensated for or not dived depending on the problem. This will be exactly the same situation as if you had calibrated in 100%. If the cells calibrate OK it doesn't mean to say they are linnier or not current limited to 1.0?

I thought your point was on choice of calibration gas? I could calibrate my KISS on any gas i like. If an ECCR would let you do the same i don't see a problem with it as long as the cells a linnier and not current limited. Hence the need for confirmation at 6m+

You said calibration on air might have a danger element and thats the premise i was questioning.

To be honest when i dived an Inspo and calibrated on 100% I would always spike the cells to 1.8 or so on the decent to ensure they wernt limited. Calibration at 1.0 doesn't guarantee the cell will read 1.6

Quote:

Your still stuck with a substantial risk of ruining your trip. It's possible that you have the same problem with mCCR (I'm guessing on that one).

Not so much

What would happen on an inspo would be loads of cell error warnings. Nothing would happen on a KISS

If a cell was 0.X out you can just accept that the cell reads high / low. However as i say you can calibrate a KISS on anything with 02 in.

ATB

Mark

Gilles · 13th October 2007, 06:31

[quote]

You said calibration on air might have a danger element and thats the premise i was questioning.

[quote]

If one relies on the fact that a replacement cell is reading 0.21 in air, that it'll read 1.x at depth, is pretty dangerous.

An in water cell check that indicates a correct PO2 is fine.

Quote:

If a cell was 0.X out you can just accept that the cell reads high / low.

Mark

The wrecks in Truk lagoon are nothing less than awesome. I really hope that IDS Bill isn't obliged to be doing maths in his head after replacing a faulty cell, with a replacement that isn't quite the same as the original.

The San Fran Maru is in 75m (and many others somewhat shallower), and one wants to spend some time there (not with a dodgy calibration).

You can always SCR your way around as a mitigation?

or bring 2 or 3 spare cells and hope one has a nominal air mV that is similiar to the one being replaced (then your old cal from home will still work assuming your new cell behaves linearly).

question: how does one multi-quote specific paragraphs from the same posting?

**Freef** · 13th October 2007, 06:55

Quote: (Originally Posted by Mark Chase)

I would have thaught you can calibrate a cell in any gas with 02 in?

If you calibrated it in 10/52 its still calibrated. Surley all you need to do then is confirm with what ever your diving on at the 6m stop or deeper.

As an example why not calibrate in air, then drop to 6m on your (lets say 80%) Your cells should read 1.28. Drop to 12m and they should say 1.76

So you have confirmed the cells are not current limited and you have confirmed the calibration.

I cant see a problem with this?

ATB

Mark

From reading the thread it looks like the controller expects to see a certain mV reading from the cells as it is "expecting" a 100% O2 calibration. Less O2 means less mV, so if the unit is waiting for the mV to rise, and it doesn't it may assume that the cells are faulty and lock out as a 'safety' feature. Unless the user can override the preset O2 level that the controller is looking for then they wouldn't be able to dive the unit.

**Freef** · 13th October 2007, 06:58

Quote: (Originally Posted by Gilles)

question: how does one multi-quote specific paragraphs from the same posting?

Just copy and paste the whole post with the (quote=someone;000000) at the start and (/quote) at the end and delete the bits you don't want...

Quote: (Originally Posted by Gilles)

question: how does one multi-quote specific paragraphs from the same posting?

...like I just did there, or, once edited, copy and paste the paragraph with the same quite delimiters, like this:

Quote: (Originally Posted by Gilles)

question: how does one multi-quote specific paragraphs from the same posting?

JS1scuba · 13th October 2007, 07:44

Quote: (Originally Posted by Mark Chase)

I didnt know there was such a thing as a minor 02 tox? (appart from lung iritation) What sort of symptoms do you mean?

ATB

Mark

Mark, high pressure oxygen can bring on certain effects that are similar in nature to nitrogen narcosis. The most common is the visual disturbances, tunnel vision, and paranoia. While some experience this only at very high pressures 1.6 atm po2 and greater others may experience it at lower pressures. Combine it with inert gas narcosis and the combination may feel greater than had the exposure been with lower oxygen and higher nitrogen components.

Cheers

JDS

JCdesign97 · 13th October 2007, 14:37

Quote: (Originally Posted by Freef)

From reading the thread it looks like the controller expects to see a certain mV reading from the cells as it is "expecting" a 100% O2 calibration. Less O2 means less mV, so if the unit is waiting for the mV to rise, and it doesn't it may assume that the cells are faulty and lock out as a 'safety' feature. Unless the user can override the preset O2 level that the controller is looking for then they wouldn't be able to dive the unit.

According to the June 2007 version of the owner's manual, the Optima HH (not sure about the other HH versions, but I assume they work the same?) will reject any cell during cal. with a mV less than 40. My three cells right now are about 6 months old and still return about 50ish mV in 100% O2; so nothing would stop me from calibrating with a low 90's% mixture; but of course this would play havoc with all subsequent calculations - solenoid firing, setpoint maintenance, PO2s, deco, etc.

For those not familiar with the Optima, the standard cal. procedure is to purge and fill the loop with pure O2 four times and on the last verify the mV readings, select 'calibrate O2' on the handsets (each separately as they are independent) and then that mV value represents 100% O2. There isn't any provision with the electronics to tell them what % the mixture really is. The new manual does describe the alternate option of putting the assembled sensor plate in a plastic baggie and flushing with pure O2, but again you're back to the supply issue.

FWIW the last paragraph of the 'CALIBRATION' section of said new manual does state "Although not endorsed by the manufacturer, alternate procedures for calibration can be found in an article published on REBREATHERWORLDdotCOM entitled Accurate PO2 Calibration. This article discusses hardware, procedures and warnings necessary to calibrate various types of Rebreather electronics using alternate oxygen concentrations and at altitude when not specifically ... by the electronics". Interestingly I just went and searched high and low for the article to link to it, but I can't find it.

Mind you I am still on my first cup of coffee - does anyone else know where this article might be??

13th October 2007, 03:56	#21 (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: 2,539	Re: Functionaing with only 92% O2 [quote] Quote: (Originally Posted by Gilles) That is key This works in practise , providing you don't lose a cell and need to change. Your holiday is jeopardised by not being able to set your cal-gas purity. This is the big down fall on ECCRs. On my KISS id just whack in a new cell and put up with what ever reading it gave me. If i know cell 2 is 0.2 out I can handle it and not miss a dive. Quote: Not without putting your life in grave jeopardy. If your cells become worn, they will tend to output less mV than needed to provide you a correct PO2 readout. Again i struggle to make sense of this. I would have thaught you can calibrate a cell in any gas with 02 in? If you calibrated it in 10/52 its still calibrated. Surley all you need to do then is confirm with what ever your diving on at the 6m stop or deeper. As an example why not calibrate in air, then drop to 6m on your (lets say 80%) Your cells should read 1.28. Drop to 12m and they should say 1.76 So you have confirmed the cells are not current limited and you have confirmed the calibration. I cant see a problem with this? ATB Mark __________________ 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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13th October 2007, 04:35	#22 (permalink)
JS1scuba RebreatherWorld Sponsor Current Rebreather/s: Classic Kiss Other Rebreather/s: Classic Kiss MK 15.X Join Date: Oct 2005 Location: Lake Havasu City, AZ - USA Posts: 422	Re: Functionaing with only 92% O2 Quote: (Originally Posted by Mixaddict) I did a week on my inspo on the Oddyssey a couple of years ago. I was getting about 94%. Did the entire week without any side effects. Obviously, I'm not suggesting that it will work for you, but I just adjusted my inspo to match what my gas analysis gave me. I don't know if that was the right thing to do or not, but it worked for me. The biggest issue for me, was that I tend to get narked a little easier on CCR than I do on OC. (Don't reall know why, but I suspect it has to do with the task loading.) Unfortunately, they don't have any helium on the boat when you are doing the really deep stuff like the San Fransisco Maru etc. Randy, the narc'd thing is something to look at. If you are running your PO2 high you may be experiencing minor effects of ox tox (many of the signs and symptoms are similar to nitrogen narcosis). You mention task loading. Not really sure why you think CCR is more task loaded than OC diving. You may also be getting some breakthrough and getting some minor CO2 issues. Try to get a better handle on that one the next time you go out. Cheers JDS
(Offline)

13th October 2007, 05:11	#23 (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: 2,539	Re: Functionaing with only 92% O2 Quote: (Originally Posted by JS1scuba) Randy, the narc'd thing is something to look at. If you are running your PO2 high you may be experiencing minor effects of ox tox (many of the signs and symptoms are similar to nitrogen narcosis). You mention task loading. Not really sure why you think CCR is more task loaded than OC diving. You may also be getting some breakthrough and getting some minor CO2 issues. Try to get a better handle on that one the next time you go out. Cheers JDS I didnt know there was such a thing as a minor 02 tox? (appart from lung iritation) What sort of symptoms do you mean? ATB Mark __________________ 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
(Offline)

13th October 2007, 05:11	#24 (permalink)
Gilles Worship the feminine Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: Den Haag (Netherlands) Posts: 762	Re: Functionaing with only 92% O2 [quote=Mark Chase;143172] Quote: This is the big down fall on ECCRs. On my KISS id just whack in a new cell and put up with what ever reading it gave me. If i know cell 2 is 0.2 out I can handle it and not miss a dive. Again i struggle to make sense of this. I would have thaught you can calibrate a cell in any gas with 02 in? If you calibrated it in 10/52 its still calibrated. Surley all you need to do then is confirm with what ever your diving on at the 6m stop or deeper. As an example why not calibrate in air, then drop to 6m on your (lets say 80%) Your cells should read 1.28. Drop to 12m and they should say 1.76 So you have confirmed the cells are not current limited and you have confirmed the calibration. I cant see a problem with this? ATB Mark On your 1st point, certain eCCR makes (that I'm familiar with ) allow you to set the cal-gas purity (down to 80%) before calibrating. Above you describe an in-water cell check. This is ok if they check ok, but what if they do not check ok? There's no means to set the low and high PO2 cal points if the nominal voltage of your new cells is different from the one that you're changing. Your still stuck with a substantial risk of ruining your trip. It's possible that you have the same problem with mCCR (I'm guessing on that one). __________________ Gilles http://www.dirrebreather.com
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13th October 2007, 05:35	#25 (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: 2,539	Re: Functionaing with only 92% O2 [quote][quote=Gilles;143178] Quote: (Originally Posted by Mark Chase) On your 1st point, certain eCCR makes (that I'm familiar with ) allow you to set the cal-gas purity (down to 80%) before calibrating. Sure, i had an Inspo that would do that. Quote: Above you describe an in-water cell check. This is ok if they check ok, but what if they do not check ok? There's no means to set the low and high PO2 cal points if the nominal voltage of your new cells is different from the one that you're changing. If they dont check OK then they are faulty and should be compensated for or not dived depending on the problem. This will be exactly the same situation as if you had calibrated in 100%. If the cells calibrate OK it doesn't mean to say they are linnier or not current limited to 1.0? I thought your point was on choice of calibration gas? I could calibrate my KISS on any gas i like. If an ECCR would let you do the same i don't see a problem with it as long as the cells a linnier and not current limited. Hence the need for confirmation at 6m+ You said calibration on air might have a danger element and thats the premise i was questioning. To be honest when i dived an Inspo and calibrated on 100% I would always spike the cells to 1.8 or so on the decent to ensure they wernt limited. Calibration at 1.0 doesn't guarantee the cell will read 1.6 Quote: Your still stuck with a substantial risk of ruining your trip. It's possible that you have the same problem with mCCR (I'm guessing on that one). Not so much What would happen on an inspo would be loads of cell error warnings. Nothing would happen on a KISS If a cell was 0.X out you can just accept that the cell reads high / low. However as i say you can calibrate a KISS on anything with 02 in. ATB Mark __________________ 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
(Offline)

13th October 2007, 06:31	#26 (permalink)
Gilles Worship the feminine Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: Den Haag (Netherlands) Posts: 762	Re: Functionaing with only 92% O2 [quote] You said calibration on air might have a danger element and thats the premise i was questioning. [quote] If one relies on the fact that a replacement cell is reading 0.21 in air, that it'll read 1.x at depth, is pretty dangerous. An in water cell check that indicates a correct PO2 is fine. Quote: If a cell was 0.X out you can just accept that the cell reads high / low. Mark The wrecks in Truk lagoon are nothing less than awesome. I really hope that IDS Bill isn't obliged to be doing maths in his head after replacing a faulty cell, with a replacement that isn't quite the same as the original. The San Fran Maru is in 75m (and many others somewhat shallower), and one wants to spend some time there (not with a dodgy calibration). You can always SCR your way around as a mitigation? or bring 2 or 3 spare cells and hope one has a nominal air mV that is similiar to the one being replaced (then your old cal from home will still work assuming your new cell behaves linearly). question: how does one multi-quote specific paragraphs from the same posting? __________________ Gilles http://www.dirrebreather.com Last edited by Gilles : 13th October 2007 at 06:33.
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13th October 2007, 06:55	#27 (permalink)
Freef Custom Title Disallowed! Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Jan 2006 Location: Land of the Freef, UK. Posts: 1,356	Re: Functionaing with only 92% O2 Quote: (Originally Posted by Mark Chase) I would have thaught you can calibrate a cell in any gas with 02 in? If you calibrated it in 10/52 its still calibrated. Surley all you need to do then is confirm with what ever your diving on at the 6m stop or deeper. As an example why not calibrate in air, then drop to 6m on your (lets say 80%) Your cells should read 1.28. Drop to 12m and they should say 1.76 So you have confirmed the cells are not current limited and you have confirmed the calibration. I cant see a problem with this? ATB Mark From reading the thread it looks like the controller expects to see a certain mV reading from the cells as it is "expecting" a 100% O2 calibration. Less O2 means less mV, so if the unit is waiting for the mV to rise, and it doesn't it may assume that the cells are faulty and lock out as a 'safety' feature. Unless the user can override the preset O2 level that the controller is looking for then they wouldn't be able to dive the unit. __________________ David. Currently owner of two differently sized ankles.
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13th October 2007, 06:58	#28 (permalink)
Freef Custom Title Disallowed! Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Jan 2006 Location: Land of the Freef, UK. Posts: 1,356	Re: Functionaing with only 92% O2 Quote: (Originally Posted by Gilles) question: how does one multi-quote specific paragraphs from the same posting? Just copy and paste the whole post with the (quote=someone;000000) at the start and (/quote) at the end and delete the bits you don't want... Quote: (Originally Posted by Gilles) question: how does one multi-quote specific paragraphs from the same posting? ...like I just did there, or, once edited, copy and paste the paragraph with the same quite delimiters, like this: Quote: (Originally Posted by Gilles) question: how does one multi-quote specific paragraphs from the same posting? __________________ David. Currently owner of two differently sized ankles.
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13th October 2007, 07:44	#29 (permalink)
JS1scuba RebreatherWorld Sponsor Current Rebreather/s: Classic Kiss Other Rebreather/s: Classic Kiss MK 15.X Join Date: Oct 2005 Location: Lake Havasu City, AZ - USA Posts: 422	Re: Functionaing with only 92% O2 Quote: (Originally Posted by Mark Chase) I didnt know there was such a thing as a minor 02 tox? (appart from lung iritation) What sort of symptoms do you mean? ATB Mark Mark, high pressure oxygen can bring on certain effects that are similar in nature to nitrogen narcosis. The most common is the visual disturbances, tunnel vision, and paranoia. While some experience this only at very high pressures 1.6 atm po2 and greater others may experience it at lower pressures. Combine it with inert gas narcosis and the combination may feel greater than had the exposure been with lower oxygen and higher nitrogen components. Cheers JDS __________________ Joel Silverstein, VP COO Tech Diving Limited a Division of Scuba Training and Technology Inc. http://www.nautilusdiveplanner.com FREE NAUTILUS DIVE PLANNER DEMO - REGISTER HERE KISS # 275
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13th October 2007, 14:37	#30 (permalink)
JCdesign97 My unit can beat up yours Current Rebreather/s: Optima Other Rebreather/s: Join Date: Mar 2007 Location: PA, USA Posts: 362	Re: Functionaing with only 92% O2 Quote: (Originally Posted by Freef) From reading the thread it looks like the controller expects to see a certain mV reading from the cells as it is "expecting" a 100% O2 calibration. Less O2 means less mV, so if the unit is waiting for the mV to rise, and it doesn't it may assume that the cells are faulty and lock out as a 'safety' feature. Unless the user can override the preset O2 level that the controller is looking for then they wouldn't be able to dive the unit. According to the June 2007 version of the owner's manual, the Optima HH (not sure about the other HH versions, but I assume they work the same?) will reject any cell during cal. with a mV less than 40. My three cells right now are about 6 months old and still return about 50ish mV in 100% O2; so nothing would stop me from calibrating with a low 90's% mixture; but of course this would play havoc with all subsequent calculations - solenoid firing, setpoint maintenance, PO2s, deco, etc. For those not familiar with the Optima, the standard cal. procedure is to purge and fill the loop with pure O2 four times and on the last verify the mV readings, select 'calibrate O2' on the handsets (each separately as they are independent) and then that mV value represents 100% O2. There isn't any provision with the electronics to tell them what % the mixture really is. The new manual does describe the alternate option of putting the assembled sensor plate in a plastic baggie and flushing with pure O2, but again you're back to the supply issue. FWIW the last paragraph of the 'CALIBRATION' section of said new manual does state "Although not endorsed by the manufacturer, alternate procedures for calibration can be found in an article published on REBREATHERWORLDdotCOM entitled Accurate PO2 Calibration. This article discusses hardware, procedures and warnings necessary to calibrate various types of Rebreather electronics using alternate oxygen concentrations and at altitude when not specifically ... by the electronics". Interestingly I just went and searched high and low for the article to link to it, but I can't find it. Mind you I am still on my first cup of coffee - does anyone else know where this article might be?? __________________ Cheers, John
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