Loose rules in Fort Lauderdale, FL

[RyanT]

Nitrox is made and checked with a certain margin of error, so "32" can mean anything from 30.5 to 34 (in my experience).

That's why you analyze your gas prior to the dive. A good shop, should be able to get you pretty close to 32 (or whatever mix you need), particularly if they bank it. 100' on EAN 32 is pretty normal. Of course nitrox carries a higher risk of oxygen toxicity. But, even with a +/- margin of error on the gas analysis and depth gauge, it's still not super risky. Let's say you analyze your gas and you get a reading of 33%. But perhaps you've really got 34% given the typical +/- 1% error. Then your depth gauge tells you that you are at 100', but you're really at 105'. That puts you at a PO2 of 1.42 instead of your MOD of 1.4. That's not really much of risk increase over the planned max PO2 of 1.4.

If you were diving a wall, then it would be really important to watch your depth. Most sites visited by dive boats, have known depths, however, which virtually guarantees you won't exceed your MOD.

 

[PfcAJ]

Nitrox is made and checked with a certain margin of error, so "32" can mean anything from 30.5 to 34 (in my experience). And at 34 your max is already 103 ft. Then there is the error of your depth gage, etc. So if we trust the tables, I'd say "borderline".

Analyze your gas....

 

[Texasguy]

Thus, after taking the dive a week ago, should I go to the emergency room right now or not (due to using nitrox)? I have Uber waiting...

 

[scubadada]

There is at least one training agency (obviously not PADI, SDI, or SSI) whose standards dictate that any dive below 100' must use Helium. Their thinking is that the risk of getting narked is too great past 100' without Helium in your mix. Obviously, there are divers who think the same way, or there wouldn't be an agency with those standards.

Sorry, that's ridiculous. I have 234 safe, enjoyable dives below 100 feet on nitrox or air

 

[boulderjohn]

Sorry, that's ridiculous. I have 234 safe, enjoyable dives below 100 feet on nitrox or air

Whether it is ridiculous or not, it is indeed agency policy. I trained with such an agency for several years, and we were not allowed to dive below 100 feet without a helium mix. At the shallower levels it was supposed to be 25/25. After that it went to standard 21/35. I was recently diving a site with some people who were part of that training with me, and they were not at all involved with training--just diving for fun. They would not go below 100 feet because they did not have helium with them that weekend.

 

[PfcAJ]

I'm part of the "helium below 100ft" crowd.

It's the bees knees.

 

[Caveeagle]

Sure for technical, advanced dives when you are already trained for mix... Maybe there is an argument for He at 100'-130'.

But for warm, open water or areas where task loading is not an issue, placing a new "He only" rule for any dive over 100' seems silly. Sure, are there some folks who might benefit from a little clearer head in that range. But If you are experienced at that depth, in decent shape and have proven to be able to handle it.. I think there might be some who are letting their own agenda take over.

Heck, I saw a diver get 'narked' and started wigging out at 90' in Blue Grotto back in the early 90's. So, if we're making rules, maybe we should back up the rec depth limits to 75' and start pumping He to everyone.

I lived through the era when people made a big deal about Nitrox. When did PADI finally get on board with teaching EAN? Mid 90's?

 

[kelemvor]

What makes a 100' dive technical? 6 hour runtime or something?

 

[Caveeagle]

What makes a 100' dive technical? 6 hour runtime or something?

There are probably a ton of potentially correct answers to this question. But here is a good example...

Several of the NFL Cave systems are right around that 100' range, which can vary +/- 5' depending on the river level. I can see a good argument for adding enough He when doing stages, multiple jumps, or maybe even diving in poor conditions, or in an unknown system in the 100'-130' range. That I can easily understand. ...Even though I still don't see it as a hard rule to be mandatory.

 

[tarponchik]

Do you seriously just dive it as whatever they tell you it is despite it analyzing as something else? If the analyzer says 34%, I'm not gonna pretend it's 32 and dive it as if it were 32.....

Your name doesn't happen to be Carlos does it?

And maybe you still believe in Santa? Oxygen analyzers used by divers in dive shops to check tanks are so inaccurate you can use them only to tell if you got air or some kind of Nitrox, and then trust in the guy who mixed it. But if I am already taking extra risk by diving solo, why would I add another risk factor? Risks do accumulate, just like errors.