Were you trained on Oxygen sensors with this level of detail?

[Capt Jim Wyatt]

Please open and read @Bobby ’s article on oxygen sensors that is attached below.

Once you have read it please answer the poll honestly. No one will know how you answered the poll.

Several of us on here are attempting to determine the level of understanding that CCR divers have regarding oxygen sensors.

 

[fsardone]

Hello Jim,
I answered yes, but I had an in depth discussion with my instructor and the only way I understood all of the issue was because of my background and my reading a couple of books and a couple of good articles. If I had only read the training organisation material, such topics are not very well covered (I'd say not covered at all) and would not have been able to understand my instructor. So instructor's knowledge and delivery capability in this area makes a huge difference.

My background is aerospace and linear interpolation is my bread and butter. Unfortunately due to the nature of things we use the cells outside the calibration interval, therefore we use an extrapolation. Your attached article explains without explicitly saying that linear extrapolation (value outside the calibration interval) are to be considered unreliable. I.e. we should be calibrating the cells at maximum expected ppO2. Which is why the 6mt O2 flush is such an important check.

When I discuss this issue with people I dive with, I very often encounter a blank stare. I guess this is why you run this poll.

Thanks!

 

[tstormdiver]

I was absolutely taught how to find/ determine the linearity of my rebreather's cells & to check that against an O2 flush & diluent flush at 20 ft. to back up what the linear calculations should be, at a PPO2 not to exceed 1.6. It has helped me to determine cells that were going bad early or other such problems with the cells, it has even helped me find defective cells that have come straight out of the manufacturer's package. I was fortunate to gain my training over the course of several months, as my unit arrived in late Oct. (the end of our yearly dive season), 5 yrs ago & being a dive shop employee, I was exposed to the concepts slowly & constantly. I was constantly quizzed over the concepts & asked to show it. It was not until the following June that I actually received training in the open water environment,... so I not only got extended classroom training, but also nearly 7 months of training in the pool environment, before going to the open water environment.

 

[northernone]

Yes, in my training it was stuck with until I had a chance at understanding to a practical result. I feel I was fortunate. In choosing my trainer I spoke many instructors and this was one of my questions I'd slip into the conversation, thanks to the forums, readings and a few mentors. I came across 6 who were unwilling or unable to respond in a meaningful way. There are more shake and bake CCR instructors out there than we'd like to think.

Regards,
Cameron

 

[RyanT]

Jim, I've been following this topic with interest, but I'm not a CCR diver. As such, I did not participate in the poll. I was wondering if, when its done, you could make the results publicly available? Thanks!

 

[Capt Jim Wyatt]

Jim, I've been following this topic with interest, but I'm not a CCR diver. As such, I did not participate in the poll. I was wondering if, when its done, you could make the results publicly available? Thanks!

Will do.

 

[wedivebc]

There are a couple of things is Bobby's paper that aren't correct but the math and the concepts work out so I voted yes.

 

[Bobby]

Dave,
Please let me know what isn't correct in what I wrote, either through a post or PM.

Thanks,

Bobby

 

[DepthCharge]

I put in a NOT SURE. My first course was 17 yrsa ago. Hard to remember if I had it in the course or learned some of it after (sucks to get old!). Also I'm not sure what point he's trying to make in the last paragraph of the article.
Later,
John

 

[Bobby]

Hello Jim,
I answered yes, but I had an in depth discussion with my instructor and the only way I understood all of the issue was because of my background and my reading a couple of books and a couple of good articles. If I had only read the training organisation material, such topics are not very well covered (I'd say not covered at all) and would not have been able to understand my instructor. So instructor's knowledge and delivery capability in this area makes a huge difference.

My background is aerospace and linear interpolation is my bread and butter. Unfortunately due to the nature of things we use the cells outside the calibration interval, therefore we use an extrapolation. Your attached article explains without explicitly saying that linear extrapolation (value outside the calibration interval) are to be considered unreliable. I.e. we should be calibrating the cells at maximum expected ppO2. Which is why the 6mt O2 flush is such an important check.

When I discuss this issue with people I dive with, I very often encounter a blank stare. I guess this is why you run this poll.

Thanks!

Fabio,
I purposely did not state a value outside of an accepted value. I have my own opinions on what value is acceptable however the industry does not. I have been chasing this subject for a long time however I'm not willing to put my neck out far enough to get caught in the liability clever.