PPO2 maximum safe value: 1.4, 1.6

[uncfnp]

http://www.leisurepro.com/p-aqutte/...m_campaign=shopping&scpid=8&scid=scsho1433743

Don't see it on Ebay now?

And DGE has one for yoke or din for 99 dollars...

https://www.divegearexpress.com/dgx-gas-transfill-hose-with-analog-gauge

 

[CuzzA]

Thanks for the links.

Imo there's no need for labeling back gas, not even with a green/yellow Nitrox sticker.

Really, doesn't that introduce complacency? The diver dives the same mix for a year and then decides one day to do a dive deeper than his MOD and has an accident. For example, perhaps he typically never dives deeper than 80 ft and uses 40% all the time, especially because he's a repetitive dive diver doing 2-4 dips a day. One day his friends want to dive a new wreck and he goes to 130 ft and now he's at a ppo2 of 2.0. He goes toxic and dies. Rather than permanently labeling for convenience which eventually may be ignored because he never considers his MOD anymore he could have maintained the practice of requesting a mix for the dive depth and labeling it as such. Which keeps him thinking about MOD for every dive.

 

[CuzzA]

I suppose a computer would help to prevent the scenario I mentioned, but not everyone uses a computer so I'm not sure that's good advice.

 

[uncfnp]

I'm probably a bad example since I tend to dive solo oriented but I have no nitrox stickers and I admit if both tanks are the same when I analyze I don't mark them since I know what is in them and I know my MOD, 1.4 to 1.6, since I dive a narrow range of nitrox 90 percent of the time. Now if the tanks differ, they get labeled.

Edit: Or iI don't plan to dive for awhile.

 

[tbone1004]

Thanks for the links.



Really, doesn't that introduce complacency? The diver dives the same mix for a year and then decides one day to do a dive deeper than his MOD and has an accident. For example, perhaps he typically never dives deeper than 80 ft and uses 40% all the time, especially because he's a repetitive dive diver doing 2-4 dips a day. One day his friends want to dive a new wreck and he goes to 130 ft and now he's at a ppo2 of 2.0. He goes toxic and dies. Rather than permanently labeling for convenience which eventually may be ignored because he never considers his MOD anymore he could have maintained the practice of requesting a mix for the dive depth and labeling it as such. Which keeps him thinking about MOD for every dive.

You have to remember that AJ is coming from the cave diving world, where stickers on tanks last for about 2 dives and then tend to be ripped off. On top of that he isn't saying never to label them, what he is saying is that you don't have to put big ass MOD stickers or the nitrox bands on your tanks. A small piece of painters tape on the crown with mix %, MOD, date, and initials is perfectly sufficient. This is why you have to have analyzers and if you are diving nitrox, you should analyze the tanks as soon as they come off of the fill station, as soon as you remove the bottle from the shop, and before you put the regulator on the bottle.

 

[Storker]

if you are diving nitrox, you should analyze the tanks as soon as they come off of the fill station, as soon as you remove the bottle from the shop, and before you put the regulator on the bottle.

I totally agree that the contents should be analyzed after filling and just before attaching the reg, but three times? At the station I fill, analyze, and mark the tank with mix, MOD, date and initials. At the site, I analyze to verify that the tank is correctly marked, assemble the gear and set the mix on my computer. Why should I analyze more than that?

 

[Patoux01]

I totally agree that the contents should be analyzed after filling and just before attaching the reg

I'm already wondering why you'd analyze twice (assuming they're YOUR tanks, not just "the same tanks as the other guys have" and that you store them at your place)

 

[Storker]

"Two is one, one is none" I work with analysis instruments, so I have a fundamental distrust in instruments and always verify important analyses. Nothing is more important than my life.

I may have screwed up the first analysis. The analyzer at the fill station may have been bad. Someone might have messed with my tank. The tape may have been torn off. If the second analysis verifies the first, I'm fine. If not, I analyze again, preferably with another analyzer.

 

[dumpsterDiver]

And pertaining to this discussion.. i think there have been cases where people have toxed out at 1.6. there was a women diving in a cave who was diving with 2 others and toxed out without exceeding 1.6 IIRC. Maybe like 5-7 yrs ago?

We also lost a women diving in the ocean in west palm who was essentially alone and she went down and never came up and was never recovered. Horrible situation, but I always suspected that a tox situation was a potential cause. This was like 5 yrs ago.

I am reasonably comfortable going to 1.6, but generally stay above that for nitrox If you dive 1.4, the risk should be less and you pretty much don't have to worry about pulmonary toxicity - regardless of how many recreational dives you do.

 

[uncfnp]

When I pick them up, I analyze. If diving the tanks soon I don't recheck unless something happens to make me question the mix. If they have been stored awhile, I reanalyze to confirm the mix even if labeled.