Question NITROX (in less than 40 foot of water)

[steinbil]

No agency is telling "air" divers to analyze their tanks in case they somehow got filled with something other than air.

GUE teaches to analyze all gas as close to the dive as possible, to minimize human error. However, they also recommend diving nitrox, and teach it as part of their basic OW.

 

[J-Vo]

I'll bite. Who would put pure o2 in a scuba tank? I assume he's writing of a full sized 80.

I have 3 AL80s of pure O2 in my garage.

 

[formernuke]

I'll bite. Who would put pure o2 in a scuba tank? I assume he's writing of a full sized 80.

I have 3 with pure O2. One needs topped off so I'm going to drop it to 80.

 

[L13]

It's easy, a analyzer takes 2 minutes to learn how to use. And will tell you if it's 21 percent.

How many dive ops have analyzers available to their air diving clients?

And anyway, if we are adding this as required training for OW, why not just finish the job and make nitrox part of OW?

 

[broncobowsher]

I used shop analyzers for a couple of years. Even remember a boat (MBT on the Oriskany) had a boat analyzer.

When I started pumping mixed gasses in my home garage is when I got my own analyzer. I got the analyzer and booster within a few hours of each other.

 

[ReefHound]

If you're going to trust the shop's analyzer, how do you know when it was purchased, when it was last serviced, when it was last calibrated? I've seen analyzers side by side read very different numbers. If your tank is marked 32% and you analyze it at 31%, is the mix off or is the analyzer off?

 

[L13]

If you're going to trust the shop's analyzer, how do you know when it was purchased, when it was last serviced, when it was last calibrated? I've seen analyzers side by side read very different numbers. If your tank is marked 32% and you analyze it at 31%, is the mix off or is the analyzer off?

Don't dive deep enough or long enough that the difference maters.

 

[boulderjohn]

If you're going to trust the shop's analyzer, how do you know when it was purchased, when it was last serviced, when it was last calibrated? I've seen analyzers side by side read very different numbers. If your tank is marked 32% and you analyze it at 31%, is the mix off or is the analyzer off?

An analyzer is supposed to be calibrated before use. If it is used by a number of people in sequence, the initial calibration is all that is necessary. When it was purchased doesn't matter, as long as the O2 sensor is replaced or adjusted as necessary. It is pretty obvious when it is necessary. The difference between 31% and 32% is not at all significant.

 

[John C. Ratliff]

If you're going to trust the shop's analyzer, how do you know when it was purchased, when it was last serviced, when it was last calibrated? I've seen analyzers side by side read very different numbers. If your tank is marked 32% and you analyze it at 31%, is the mix off or is the analyzer off?

I am a retired CIH (Certified Industrial Hygienist). In my last job as a CIH, I was manager of safety and health for a chemical company. We had times when we needed to analyze for chemical contamination (ammonium hydroxide, HCl, and other gases). We had a professional gas analyzer too, with a cylinder of calibrated gas. When we made measurements, we needed to do the calibration before we measured, and after, and record what the readings were on the meter.

I see a pretty cavalier attitude when doing the oxygen analysis, saying that the gas needed to be analyzed before diving. I don’t see much about calibration of these meters. If, as many here state, your life depends upon a very accurate measurement of the amount of oxygen in the tank, then you need to also take calibration seriously too.

I find these technical divers are rather fanatical about testing; I’d like to see them just as fanatical at calibration of their meters, and recording their findings. If you ever need to go to court about an trimix fill, and you have not calibrated your instrument (preferably before and after taking the sample), you may not have much to stand on in a legal case.

SeaRat

 

[ReefHound]

I am a retired CIH (Certified Industrial Hygienist). In my last job as a CIH, I was manager of safety and health for a chemical company. We had times when we needed to analyze for chemical contamination (ammonium hydroxide, HCl, and other gases). We had a professional gas analyzer too, with a cylinder of calibrated gas. When we made measurements, we needed to do the calibration before we measured, and after, and record what the readings were on the meter.

I see a pretty cavalier attitude when doing the oxygen analysis, saying that the gas needed to be analyzed before diving. I don’t see much about calibration of these meters. If, as many here state, your life depends upon a very accurate measurement of the amount of oxygen in the tank, then you need to also take calibration seriously too.

I find these technical divers are rather fanatical about testing; I’d like to see them just as fanatical at calibration of their meters, and recording their findings. If you ever need to go to court about an trimix fill, and you have not calibrated your instrument (preferably before and after taking the sample), you may not have much to stand on in a legal case.

SeaRat

Nothing like a technical discussion to bring out the perfect people. Nobody said a word about calibration until I mentioned it and now they will tell us how they carefully calibrate every day.