Gas testing and sidemount

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Originally Posted by BobK

Actually, I think you missed my point. The original issue was how a low PPO causes a person to lose conciousness. You brought up skiing and stuff in air, which I contend does not represent underwater conditions. I pointed out that people breath gas in a chamber that would tox them underwater under the same pressures, to point out that the water and air environments seem to play into the equation.

So, based on the above, I think that skiing in a low PPO environment is not an indicator of what will happen to a diver in the same low PPO environment. Perhaps you have a study or some research that shows this not to be true ?

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I agree. But I think a bigger difference is the lack of time to acclimate to low PPO2s in diving. On a climb you have several hours to several days or weeks to acclimate as you move higher. Air versus water in and of it self probably has nothing to do with it, rather it is acclimatization and workload.

Why is this thread still going?!?!? Stop being lazy and analyze your damn tanks!!!!! Even if getting them filled from what is suppose to be a banked system, mistakes can be made. Anyway 8 pages of BS really.

The thread is not what you'd call active, it just floats to the top anytime someone responds to the poll. 93% of the respondents testing both tanks is not great, but not bad either - assuming that the poll respondents reflect the actual population.

It's total crap. Ask any tank monkey at a major cave shop if 93% of their customers test every time. Hell, just sit there and dring a soda and watch for 1/2 hour.

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Originally Posted by aainslie

It's total crap. Ask any tank monkey at a major cave shop if 93% of their customers test every time. Hell, just sit there and dring a soda and watch for 1/2 hour.

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LOL Andrew! Yep, I don't think it's quite at 93% yet....

Safe diving,

Rich

P.S. Please disregard my crotchety comment elsewhere..... :)

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Originally Posted by aainslie

It's total crap. Ask any tank monkey at a major cave shop if 93% of their customers test every time. Hell, just sit there and dring a soda and watch for 1/2 hour.

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It's hard to tell based on action at the shop. It's rare for me to test gas there, I normally do it at the site when the regs are attached. I normally sample off the QD fittings and I prefer to sample during the gearing up process as it eliminates the potential for any switch or confusion among the various tanks.

But yes, the most probable explanation here is that a large number of the respondents are giving socially acceptable/expected responses rather than honestly reporting their actual behavior.

What would be very interesting to research is how often those respondents also respond to other polls or post in a manner that also reflects the "right" thing to do, when those action are also not consistent with what they actually do in a cave.

waiting until you leave the shop to analyze seems silly to me. what if the fills are all cocked up? then you have to drive back to fix it

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Originally Posted by LiteHedded

waiting until you leave the shop to analyze seems silly to me. what if the fills are all cocked up? then you have to drive back to fix it

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I suppose it depends on the dive site and the dive you are planning. For instance if you are diving Peacock, then you could always just run back over to the fill station to get it fixed - or use the gas you have so long as it is acceptable (I.e. air vs 32%). If I were diving eagles nest, I would probably anaylze at the shop as I would be pickier about my mix and the hassle of returning to a dive shop would be higher. IMO most of the common dive sites fall into the first category.

Cheers,
Jeff

It also gets us back to the original question of the complexity and visibility of the fill station. For example, as previosuly metioned with Dive Outpost, where everything is openly visible on the wall and the air and nitrox banks are distinctly marked with distinctly traceable tubing, valves and fill whips, unless they have totally misfilled a bank, I am going to get the 32% I ordered. In addition, with all the tanks connected to the same fill manifold, if I test one tank I have a reasoanble degree of confidence that the other tanks are also going to be 32% as well. In that regard, at least to me, it makes more sense to verify the mix when I am geared up and ready to go so that I am 100% sure the tank ha in it what it is supposed to have in it.

In a slight contrast, at Rennakers with air, nitrox, O2 and helium all routed through a much more complex fill panel where it is potentially easier for someone to make a mistake, I am much more likely to analyze the gas on the spot, unless I am able to verify the whips and valve positions myself - which usually depends on how busy they are at the moment.

At the other extreme, if I show up at the boat for a trimix dive, the tanks will have been analyzed to verify the mix at the shop (and if it is at the "home" shop, I will also have done the mixing myself), and depending on the time between fill and analyzing, they may get re-checked later, before boarding the boat.

The bottom line is that they all get analyzed, the "when" just depends on when it makes the most sense. Always doing it at the shop probably does not make any more sense than always doing it at the dive site.