Nitrox analyzer: to take or not to take?

[scubafanatic]

I always bring mine, beat standing in line behind 20 other divers waiting, or searching out where the last diver laid it down somewhere.

 

[Jake]

Just an additional comment here.

When you get your own, get the BCD adapter for the hose. It makes the process so much quicker and easier, not to mention quieter.

Plus if you’re like me and hate to waste “all that air” testing it without the adapter, you don’t waste that 1/20th of a breath from your tank

So how do those work exactly? I haven't been able to find anything showing it in actual operation.

Is it something that goes between your disconnect and the LPI?

 

[jstrang]

I just got back from a trip to a very remote location They had one analyzer but it busted the morning we arrived. With no place to get another one, the dude used mine for blending and we all used it for testing our tanks. I ended up leaving it there so he had one.

Come on. We would have been fine if he just guessed it - a little air, a little O2 and viola a mix that is safe to dive - who needs an analyzer.

 

[Stoo]

Come on. We would have been fine if he just guessed it - a little air, a little O2 and viola a mix that is safe to dive - who needs an analyzer.

LOL ya... Dive until ya twitch~

 

[Storker]

im assuming you l have to check and sign for your nitrox? so its already been checked at blending and then again at signing with a different analyser

That's also a great way to safeguard against a current-limited cell, since the risk of two cells failing with the same current ceiling at the same time is pretty small.

In my class we were taught that we had to calibrate the analyser before checking the tank. Wouldn't that make a second analyser moot?

You calibrate against air, don't you? A failing cell may well be able to be calibrated to 21%, but then give too low values for a richer mix. Electro-galvanic oxygen sensor - Wikipedia

The only proper way to get around this is two-point calibration: Both on a leaner mix and a richer mix than the one you're planning to breathe. Since that usually is rather impractical for us OC divers, checking with two different analysers - for me that's typically one analysis just after filling and one analysis at the site - gives you a bit of a safety margin: If both calibrated analysers give you an fO2 within about a percentage point of each other, you can be reasonably sure that you're OK. If they differ noticeably, one of them is giving the wrong reading. Since you then can't know which one is right I personally wouldn't breathe the tank until I had access to a third instrument which agreed with one of the two others.

 

[JackOfDiamonds]

It depends on the dive club and the location , most of the places ive been to have very well maintained gear and club so the analyzers are pretty good and always cared for.

With that being said, i did bring my own (technically burrowed from a friend) when i went to Sinai because i simply don't trust their equipment.
(I also made double sure to stand as far away as possible when they were filling up tanks).

I usually go on a 1.4 setting but even with the added safety precaution i still wouldn't want to risk going down on a wrong mix , you can never know what will happen during that dive.

 

[maj2]

I bring my own just so I do not have to wait for my turn to use the communal analyzer.

 

[hroark2112]

So how do those work exactly? I haven't been able to find anything showing it in actual operation.

Is it something that goes between your disconnect and the LPI?

Disconnect the inflator hose. Plug in the analyzer. Turn on the tank valve. Turn off the tank valve. When the reading stabilizes, you're done. Don't forget to plug your inflator in again!!

 

[tc]

I’ve carried my own analyzer on trips for 9+ years. I rarely see a variance exceeding 1%, on only a couple of occasions I’ve see a few points more and every single time it was due to an older sensor- either mine or theirs.

Replacing the sensor at least every 2 years, 1 if accuracy is critical, seems to be the answer for me to get accurate readings.

 

[northernone]

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A ScubaBoard Staff Message...

Discussion of oxygen analyzer failure split into a new thread:
Oxygen sensor failure

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