NITROX CERTIFICATION PROTOCOLS - REAL WORLD

[BRT]

HELLO. I just got my NITROX certification. All went well. However, as my instructor was going through the training of testing my tank with the oxygen analyzer, she stressed over and over again how it's my responsibility to test the tank before each dive and to ensure that the proper labels are affixed to the tank (name, date, O2, etc)...She was very firm on these issues and I appreciated her passion for teaching...

OK, question. I recalled several months ago, I went to Cozumel to dive for a month. I was pretty new to diving and I dove with some pretty experienced, dive masters, instructors, etc...THEY ALL USED NITROX. (I didn't because I wasn't certified at that point)...But, I never saw any of them, EVER, test the tanks before the dives. I don't even recall seeing an O2 analyzer anywhere.

I dove the entire month with a reputable LDS, who I bet was pretty careful to test the tanks before setting up the dives...And of course, all dives went off without a hitch.

So...what gives? Is this one of those things where you train ONE WAY but perform real world functions ANOTHER WAY??? Should I invest in an O2 analyzer. When diving should I insist that I personally test my tank. Will I be holding up the whole operation?

OR...SHOULD I JUST GO ALONG WITH THE CROWD AND TRUST THAT THE LDS HAS DONE THE LEGWORK?

Thanks everyone for your help. ))

We seldom see an analyzer in Coz. We take our own.

 

[Scraps]

It’s important for divers not to allow a dichotomy to exist in their minds between their training environment and some imaginary place called the the “real world,” where renegades, outlaws, people bad at math, and lazy people get to define the norms.

The real world is the place where physics and physiology govern with complete indifference to us. It’s a place where things go wrong, but don’t go as far wrong when you are conscientious about maintaining the practices, habits, attitudes, and safety margins you were taught.

Maintain the resolve to make your real world comport with what you know is the right way to plan and execute your dives. .

The alternative is to go down the road of ever greater variance from those standards based on the people you meet who haven’t yet been killed by whatever variances they’ve come to accept as normal.

Your Nitrox instructor was absolutely correct about practices you should follow to stay alive longer in the real world.

 

[RayfromTX]

A few months ago I tested some tanks that were labeled as 28%. They tested at 32%. Hmmm I guess my planned dive to 40 meters is going to have to be adjusted. Then I hooked them up and the pressure was low. I then knew what had happened. I pulled out my phone which has a gas blending app on it and plugged in the pressure and 32% and then topped with air to 3,000 psi and sure enough it came up 28%. The fill station had forgotten to top with air. If I hadn't tested and just figured I got a short fill and gone to 40meters for 10 minutes, I might have had a bad day. Instead I drove back to the fill station and had my three tanks topped off with air and went back to do my dives.

ALWAYS TEST

It helps insure you will have a good day.

 

[Russjstewart]

A similar tale to RayfromTX, I had been diving with an op for a couple of days, and the mix had been spot on. The op insisted everyone test, label and sign off on the fills. On the 3rd day I stopped testing when the analyser got to 60%, and asked for a need tank..

 

[lowwall]

That said...if you're willing to buy and maintain in working order an O2 analyzer, they can be pretty small, analysis doesn't take long, and I imagine other people on the boat will ask to borrow yours once they see you with it (if you're not willing to share, that can create awkwardness and ill will, so think about how you plan to handle the situation). If you're friendly, polite, non-confrontational and if questioned say something like 'No offense. I was trained so hard on this, it just gives me peace of mind if I analyze it myself," I think that'll work fine.

Some may say you should confront dive op.s on their allegedly unsafe practice if they provide tanks without analyzers; that's up to you. I don't.

This reminded me that someone on my boat for a few of the days I was diving with Aldora did have his own tester and double-checked all of his tanks. I asked and he told me they always matched within a couple of tenths.

Thinking back, most of my nitrox dives in Coz, Little Cayman and off Boyton Beach have been with trust me labels that I didn't verify. But these were all with highly respected dive ops. OTOH, it was boat policy to verify and log every one of my 60 or so nitrox dives over two trips to Thailand.

 

[Centrals]

Always analysed the tank before the dive and labelled it myself. some operators even has a log book to sign.
There is NO such thing as trust me.
Any operators that prepared their own nitrox should have analyser available. Can't say the same on those sourced from a provider. This is the kind of operator that I would avoid.

 

[Scubagolf]

I did 18 Nitrox dives at Scuba Club in June. I directly observed the testing, and I filled out the label and put it on the tank.

 

[Hojo in SC]

As others said, test the tank, label it with the exact mix, label it with the max depth as a reminder and for your buddy to see if you forget how deep you can go.

And finally, how do you know that the other divers had Nitrox, maybe the tanks had the label but was filled with 21% oxygen.

 

[KenGordon]

It only takes a few minutes for the gasses to diffuse: How Quickly Do Gases Mix?

Actual experience shows that it can take a while to settle. This is especially true of rich deco mixes. I am not too worried about how 30 bar of o2 gets mixed into 200 bar of air, that does seem to happen immediately.

 

[KenGordon]

HELLO. I just got my NITROX certification. All went well. However, as my instructor was going through the training of testing my tank with the oxygen analyzer, she stressed over and over again how it's my responsibility to test the tank before each dive and to ensure that the proper labels are affixed to the tank (name, date, O2, etc)...She was very firm on these issues and I appreciated her passion for teaching...

OK, question. I recalled several months ago, I went to Cozumel to dive for a month. I was pretty new to diving and I dove with some pretty experienced, dive masters, instructors, etc...THEY ALL USED NITROX. (I didn't because I wasn't certified at that point)...But, I never saw any of them, EVER, test the tanks before the dives. I don't even recall seeing an O2 analyzer anywhere.

I dove the entire month with a reputable LDS, who I bet was pretty careful to test the tanks before setting up the dives...And of course, all dives went off without a hitch.

So...what gives? Is this one of those things where you train ONE WAY but perform real world functions ANOTHER WAY??? Should I invest in an O2 analyzer. When diving should I insist that I personally test my tank. Will I be holding up the whole operation?

OR...SHOULD I JUST GO ALONG WITH THE CROWD AND TRUST THAT THE LDS HAS DONE THE LEGWORK?

Thanks everyone for your help. ))

Do as trained. Analyse your gas. If the dive ops you use don’t provide an analyser then buy one.

I have encountered mislabelled nitrox mixes when the dive op’s analyser was in need of a new cell. I have also encountered a shop that swore blind by left over trimix was air due to a failed helium sensor. Stuff breaks and it is good to notice. Don’t forget your own stuff breaks too…