dive tables

[NAM001]

after using a nitrox mix and recharging to full preasure with air, the mix is no longer a standard 21,32,36%. perhaps 27 is the resulting mix. where do i get tables for that mix and subsequent reducing mixes untill the tank finally gets back to 21%. is there a reference that will give me tables for 25% or 29% other than the naui white wheel that converts depth at % to the 21% tables???
possibly a software package or a site to download the tables from. it sems silly to use the more conservative of the computer vs. % table in planning, knowing the table always wins. then to be cut off from the appropriate tables and made to rely on the computer that up till now has not been the conservative choice.

example. 36% nitrox dive return at 800lb. recharg to 2610 with air the resultant mix should be somewhere around 26% where is the table for 26% mix?? 29%??

is this something to adress to naui or padi ect ?????


regards

 

[jviehe]

No, what they teach is to find the equivelant air depth, and use the air tables. I simply use my computer for odd percentages, which seems to be what you want to do anyway, as the computer is just digital tables. I dont know if theres something printable out there, though.

 

[scubasean]

I agree....My (recent) nitrox class taught me to analyze the mix in the tank, and then use the EAD table in dive planning to find the equivalent air depth of a particular portion of a dive plan, then use the air tables for NDL's fo that portion and SI, then move on to other portions, keeping in mind the O2 issues as well.

Or, a computer handles these on the fly as well.

Interesting question though would be if you walked into a shop and asked for an air fill, telling them also that 32% was in the tank previously, would they empty the tank, refilling with air? I wonder...

I'll have to ask at my LDS what they would do.

In any case, that brings up a point I hadn't thought of and wasn't taught in class (directly anyway...) which is to analyze the mix in a nitrox-labeled tank even though you think it is (hyperfiltered) air.

 

[cornfed]

scubasean once bubbled...
[B
Interesting question though would be if you walked into a shop and asked for an air fill, telling them also that 32% was in the tank previously, would they empty the tank, refilling with air? I wonder...
[/B]

Why would you tell them anything they don't need to know?

 

[Genesis]

make DAMN SURE you analyze and label the contents of that tank!

 

[Charlie99]

KWS once bubbled...
..is there a reference that will give me tables for 25% or 29% other than the naui white wheel that converts depth at % to the 21% tables???
possibly a software package or a site to download the tables from.

A good set of equivalent depth conversion tables is at http://www.gooddiving.com/Doc/EquivalentNitrox.pdf

Those tables are for 22% to 40% nitrox, and convert from the 10' increments of whatever air table you choose to use, over to the equivalent nitrox depths for the mix you are diving. In other words, it is an Equivalent NITROX depth table.

The formulaes and method of calculating equiavlences for NDL and decompression purposes should have been covered in your nitrox class.

 

[cornfed]

Genesis once bubbled...
make DAMN SURE you analyze and label the contents of that tank!

Or you could dive the original nitrox MOD and use air tables.

 

[Genesis]

the problem is that without a label on the tank someone (including you!) might grab it and think it has regular air in it..... and if you were diving deep, that could be quite bad.

 

[cornfed]

Genesis once bubbled...
the problem is that without a label on the tank someone (including you!) might grab it and think it has regular air in it..... and if you were diving deep, that could be quite bad.

I don't use other people tanks and they bloody well better not use mine.

 

[Genesis]

would have trouble using my tanks, as they're DIN-valved and most of the people I dive with are yoke-type people.

Nonetheless, I might kill MYSELF if I don't label my own tanks, and that's at least as bad!

Any tank of mine without a label is treated as having both an unknown pressure and FO2; until both are verified it cannot be used. That includes tanks of air; if it doesn't have a contents label, it may as well be full of CO from my point of view.