Oxygen analyzer

[KenGordon]

I have met faulty analysers supplied by dive ops.

This happened at the same time as the cell in my analyser failed. The battery in the op's analyser was shot, so I replaced it with the one from mine. Then it turned out the cell was on its way out too and claimed 94% for pure o2.

A classic was when the helium cell failed at a LDS. Nobody would believe it until they tried it with gas directly from a J.

 

[pdhenry]

Wow. Nitrox Rule #0 is that the diver analyzes his own tank (or witnesses its analysis - it's not necessary to operate the analyzer). At the shop I dive in NC they have 30% banked (MOD on 32% is a bit too shallow for some of the popular wrecks) and we analyze the night before after they've been refilled from the day since the boat sometimes loads up and gets underway before the shop opens in the morning. Someone who shows up in the morning to dive air won't have seen us analyze the tanks.

A question on the low battery/bad analyzer issue: How much does calibrating the sensor with a tank of air expose these issues?

 

[KenGordon]

It was pretty obvious but I was checking air and pure oxygen. My failed cell had been OK a month before (this was January) with air, 40% and 70% so I was surprised at how bad it was, I recall it only reading 45% with pure o2 having be set to 21% in free air.

The bad battery was obvious, I think there was some blinking LCD to indicate this. However that cell which gave 94% in pure o2 might lie convincingly with 32 or some other typical mix. If I ask for 32% and it analyses as 30% I am not totally surprised.

 

[archer1960]

The place I was at in Cozumel had you test your Nitrox tank before you left the shop (actually, you watch them use the tester and read the number off it, because they're better at it), then you write down the information while they move on to the next person's tank.

 

[Anthony A.]

Is there any use buying an o2 analyzer if you strictly dive air? I never exceed 110' depth and only dive air but wondering if there is any use getting an o2 analyzer to make sure overseas dive ops are actually giving me air. Am i just being paranoid?

 

[soggybadger]

I know that by the book everyone should analyze their tanks and fill out the forms and label their tank prior to diving. Recently got certified after doing an online class and then completed the remaining portion at a dive shop on vacation. Now, from experience, I have been on resort diving where the boat picks you up at dock. You get on and people who are diving enriched air have their tanks ready to go. Perhaps I didn't happen to notice but I have yet to see anyone of these divers analyze their tanks. They strap on and off they go. I spoke to my friend I went diving with and he said that he has never "had" to analyze his tanks in the past (he's been EAN cert prior). I also don't think he is far from the norm.

Anyways, I analyzed all of my tanks at the shop prior to leaving and my friend did his also ( with my reminder of procedure). Go figure, one of our tanks was 98% oxygen! NO FREAKIN' WAY!!! What better way to instill the respect of the safety procedure that i was trained on then to potentially die if I didn't do this! The dive op is very professional and makes everyone do their own tanks and the formalities for diving EAN. The Blender was in awww and said it was impossible but clearly it wasn't. The others dialed in 32% right on. He was very apologetic but thinking of the possibilities really made me think of how many people take it for granted they are on the correct blend.
Scared the crap out of my friend because this is the first op that ever made him do it himself and just took the shops word for it.
This will be something I will be very diligent on for ever. Obviously!! But how many people actually check their tanks when loading directly onto a dive ops preloaded boat? How many people, when the dive op doesn't ensure you check, request an analyzer and an analyzer is actually on the boat? I'm definitely considering purchasing my own analyzer for such situations... Curious as to how other divers go about for their "life" insurance (analyzer) and ensure their own safety for lackadaisical dive ops
Dave

Good job you did things correctly.

 

[HJeffreyM]

Anthony A,

The short answer is no. If you never plan to dive anything but air, there is no need to buy an O2 analyzer. You may want to invest in a CO (carbon monoxide) analyzer. You may want to look up Dandy Don’s numerous posts on this subject. CO in your tank could make for a very bad day.

 

[Anthony A.]

Anthony A,

The short answer is no. If you never plan to dive anything but air, there is no need to buy an O2 analyzer. You may want to invest in a CO (carbon monoxide) analyzer. You may want to look up Dandy Don’s numerous posts on this subject. CO in your tank could make for a very bad day.

Thanks, yeah im definitely getting a co analyzer. Just wanted to know if oxygen would be needed also. Is it even possible to fill a tank "air" but not not 21.9% oxygen?

 

[HantsDiver]

Is there any use buying an o2 analyzer if you strictly dive air? I never exceed 110' depth and only dive air but wondering if there is any use getting an o2 analyzer to make sure overseas dive ops are actually giving me air. Am i just being paranoid?

Yes. High o2% at 110' (or 33.5m in sensible units) will knock you out and kill you quickly.

The chances of it happening are small. The consequences are huge. Check it and you are sure - even if the analyzer cell is junk you will know something is wrong. You have nothing to lose (save some $$) and potentially your life to gain.

 

[guruboy]

Thanks, yeah im definitely getting a co analyzer. Just wanted to know if oxygen would be needed also. Is it even possible to fill a tank "air" but not not 21.9% oxygen?

Air is 20.9% O2