Nitrox analyzer?

[Damselfish]

I have been kjnown not to analyze when after repeated fills and havng good mix, i have watched oame or all the fill or have had a fill bfrom banked fills where 30 or more tanks have been group filled. you see others check theirs and it is good so yours has to be. never do i not check on a single tank fill or a custom fill.

The trick with this is when someone mixes up tanks or whips if you weren't watching all the time, it really depends on the setup. I've even been on a liveaboard where someone accidentally put a Nitrox whip on someones air tank. Someone noticed quickly (crew member freakout here), but the fact that the Nitrox being pumped is consistent doesn't help if someone is sloppy in some other way.

 

[Gareth J]

We always analyse.

I would guess we have a minimum of three analysers on a boat at anyone time.
As is the 'standard', cylinders are always analysed and labeled at the gas station.

But they are always rechecked before the regulators are fitted on the boat. With 12 divers on a boat, and stage cylinders, and potentially cylinders for the second dive. There are too many cylinders, so always a risk of the wrong cylinder being used by the wrong diver, or even a diver confusing a cylinder. The main thing to remember is people make mistakes. Double checking reduces human error.

Hire cylinders make the risk of mistakes worse. At least with your own cylinders, the risk of confusion or mistakes in identifying cylinders is markedly reduced.

Gareth

 

[islanddream]

I was on a dive boat in the Caribbean, the DM was analyzing the tanks and we had to sign off on what he came up with. As I watched him analyze my tank, I could tell the analyzer wasn't properly snugged up against the valve. When he handed me the clipboard with with 32% on it (I dive 36% most of the time), I asked him to reanalyze. He wasn't happy with my request but did reanalyze my tank. When he did, the analyzer was place properly and the reading came back at 36% Nitrox. I watched him analyze my tanks the rest of the trip.

 

[tursiops]

No requirement to personally analyze. The requirement is to verify the analysis, which usually -- on a liveaboard -- means watching the deck guy calibrate and analyze.

 

[NAM001]

The trick with this is when someone mixes up tanks or whips if you weren't watching all the time, it really depends on the setup. I've even been on a liveaboard where someone accidentally put a Nitrox whip on someones air tank. Someone noticed quickly (crew member freakout here), but the fact that the Nitrox being pumped is consistent doesn't help if someone is sloppy in some other way.

I agree totally. I dove the texas clipper in south padre island in south texas. The operator of the shop is Tim Oleary, the head tec guru for Nauii. I say shop somewhat loosly. His operaion is truely a business and not a store front. He has professioals where ever you look. I watched them fill tanks there were lats say 50 tanks being filled at one time I believe with nitrox. O2 injected nto the compressor input not PP blending. when teh tanks were pulled and a couple were sampled at say 32.1 and all tnks were filled tehsame eth day before you have a pretty good idea just what is in your tank when you get it. at the dock tanks were being checked with personal testers. they varied but all tanks tested by the same tester read the same. they did not vary more than a couple of points tester to tester. when you hear the numbers coming out you really have no fear of what is in your tank. Kinda like you are hearing the results of a batch and you are pert of the batch. The first days fill was done by draining the tanks so the resultant fills on all tanks would be all the same. These folks know what they are doing. That day i did not even break my tester out. another divers tank had some unique markings and i saw it and mine on the same fill system at the same time on the same compressor run. Did I make a gamble yes was there much at stake , perhaps. odds were very much on my side 99 to1 being a good fill. You can not take that chance when you go into a shop and you get a fill not knowing if your tank got mixed up with some one elses .

 

[Oz Chris]

Like others have noted there's an answer missing. I always test and label every tank myself, but I use the shop/operator's tester (will get my own at some point).

I always check the calibration myself before I use the tester. One great shop I dove with had a dedicated tank of 21% in the tank room so you could calibrate before every tank.

 

[TMHeimer]

I rarely use nitrox and when I do I rent a couple of tanks when away from home. And keep them with me the whole dive day. I watch at the shop when the analyzer is calibrated and what the % O2 reading is. I figure it is no more likely that there is something out of whack with the shop's analyzer than it would be if I spent the bucks and bought my own. Some suggest viewing the shop's analyzing then re-checking it with your own. I figure it's not worth the expense of buying one for the rare time I would use it. The old risk assessment thing.

 

[seeker242]

1 and 4 would qualify as true. Always analyze personally, but not necessarily using my own personal analyzer.