Gas analysis and team diving...

[InTheDrink]

Re reanalyzing on the same day -- if the tanks have been under your possession and control from the time they were filled/analyzed by you, do you still re-analyze on the day of use? If so, Why? What do you think might have happened? OR is it just out of an abundance of caution to re-confirm what you first put on the tape?

In my (our) case, our tanks are filled at a shop, we pick them up, analyze/tape and then take them home where they sit outside behind our house. It is certainly possible that someone could come through the gate, to the house, to the tanks and mess with them -- but so is it possible to get hit by lightning.

Do circumstances, perhaps, dictate the procedures?

Your post is completely logical and I can't argue with that.

However, I don't even trust myself and if it's been a day or two, who knows what I was thinking back on Thursday. Human error is so prevalent in pretty much everything.

I just don't see the overhead as big enough to not re-test immediately before the dive. It's also a safety blanket for me so it's one more definite known. But there again, I inherently distrust equipment, not necessarily logically, so it may just be a personal peccadillo.

I also agree that trying to avoid being late is key to not cutting corners.

Anyhow, glad everything and everyone's ok.

J

 

[lamont]

Re reanalyzing on the same day -- if the tanks have been under your possession and control from the time they were filled/analyzed by you, do you still re-analyze on the day of use? If so, Why? What do you think might have happened? OR is it just out of an abundance of caution to re-confirm what you first put on the tape?

In my (our) case, our tanks are filled at a shop, we pick them up, analyze/tape and then take them home where they sit outside behind our house. It is certainly possible that someone could come through the gate, to the house, to the tanks and mess with them -- but so is it possible to get hit by lightning.

Do circumstances, perhaps, dictate the procedures?

I don't like diving off old stale analysis stickers. Maybe that was a tank that I got topped off and forgot to remove the analysis sticker when it was filled and who knows what is in it now (I always try to remove analysis stickers when get goes into the tanks, but I wouldn't want to bet my life on that procedure).

If I analyzed it last night, then I'm a lot more comfortable with that. If I've forgotten exactly which day it was filled and analyzed, then that is probably too long ago.

 

[japan-diver]

We always retest on the day of the dive as my tanks are at my shop and we are usually grabbing out of a pile of about 100 or so and someone might have refilled and not tested or marked. If they were in my possession the whole time and I was the only one who touched them I probably would trust a test I did a day or two before.

 

[RiverRat]

Always second guess everything. I had a friend fill my doubles once for a routine shallow dive in the quarry. I told him please empty them as I had loaned them out to an instructor for a student to use in a class. I told him I have no idea what gas is really in these doubles. I go and pick them up at the shop and while loading them in the truck I ask, "so you drained them and filled with air right?" Well no.......I topped them off. So I explain AGAIN why I wanted to drain them and the response was we're diving shallow it shouldn't matter I analyzed them well over 21%, high 20's I think or higher. My mind started to play all kinds of potential disaster scenarios. What if we called off that dive and I stored them in the garage for 2 weeks and then "assumed" they had air in them? So now I go and do a dive on a hot mix? I learned that day not to trust anyone as mistakes can and will happen if procedures are not strictly followed. If you're not there to watch the fill process never assume what gas is in the tanks without checking yourself.