Loose rules in Fort Lauderdale, FL

[kafkaland]

I'd much prefer EAN 32 over air for a dive to 100 ft. My PPO2 is 1.29 instead of 0.85, that means my single-dive O2 time is 180 min instead of 360 min. But my NDL has increased from 20 min to 29 minutes. So what's limiting here? The nitrogen, not the oxygen. Now, even if the mix was off by 2% and I was unwittingly diving EAN 34, the PPO2 would be 1.37 and the oxygen time 150 min. Not even close to dangerous. To get into the dangerous terrain, you'd have to have 40% in your tank, for a PPO2 of 1.61, and an O2 time of less than 45 minutes. And that's still more than your NDL and in all likelihood nothing bad would happen, but since O2 toxicity has much more dire consequences than overstaying your NDL by a bit, you wouldn't want to push that limit. And, I do trust my own. analyzer and the dive shop's analyzer enough that if both tell me it's 32%, that I'm sure that I'm not getting 40%.

 

[uncfnp]

The VIP is not a legal requirement. It is, possibly, an industry standard and profit center for dive shops. While I consider it a useful convention and I would not put a decal on if I did not follow the process as defined (by who) but exactly what rule was broken? He charged you for a decal that he installed, so you got the decal and the fill. The decal has no legal definition or requirement. What CFR or state regulation specifies the specifics of a annual visual cylinder inspection for consumer SCUBA tanks not used in commercial service?

N

It disturbs me in that it is an indication of the work ethic of that individual and perhaps the shop if they consider that acceptable. It raises the question of what other short cuts that shop takes.

 

[kensuf]

I wonder how you manage this? If you have a solid grasp of what you're talking about, you do know, of course, that there is no oxygen tank where we divers pick up Nitrox.

AJ's been known to do a technical dive involving oxygen decompression at least once or twice in his life. I think that's where he has found a bottle of pure oxygen.

 

[kensuf]

No, I don't. I analyze everything I breath. Air-100% oxygen.

There's no 'trust' involved.

Air's for tires AJ.

 

[kombiguy]

So, according to one poster, you can't trust the tank filler, the analyzer, the maker of the analyzer, the gas supplier, the dive shop, or anyone else involved in the production, testing, or supplying of gas.
Good luck snorkeling the Spiegel Grove. That is, of course, if you trust the boat captain.

 

[rivers]

I wonder how you manage this? If you have a solid grasp of what you're talking about, you do know, of course, that there is no oxygen tank where we divers pick up Nitrox.

The dive shop where I get most of my fills can fill anything from air, nitrox, pure O2, and trimix. As does the shop where I get my second most fills. I can pretty much get any fill I want, except hypoxic trimix, which is due to my certification level and not the shops ability.
Not every shop has banked nitrox. Most in the UK use partial pressure blending. A couple use continuous blending, and I know of maybe one shop that banks nitrox, but they still do PP blends, O2, and trimix. You're talking bollocks mate.

 

[Caveeagle]

So, according to one poster, you can't trust the tank filler, the analyzer, the maker of the analyzer, the gas supplier, the dive shop, or anyone else involved in the production, testing, or supplying of gas.
Good luck snorkeling the Spiegel Grove. That is, of course, if you trust the boat captain.

"Trust but verify"

I would not buy gas from anyone who I did not trust. But to ignore the possibility of human or mechanical errors, is like nominating yourself for a Darwin award.

 

[uncfnp]

@tarponchik. We all choose our margins of safety. If you have made an informed decision that Nitrox is borderline safe at 100 that is perfectly fine and a correct choice for you. The issue is that you made it as a broad statement and not an individual choice. As others have pointed out, it is not a margin others accept. And also as pointed out, the justifications for your choice are not valid.

 

[kombiguy]

"Trust but verify"

I would not buy gas from anyone who I did not trust. But to ignore the possibility of human or mechanical errors, is like nominating yourself for a Darwin award.

Sort of my point exactly.

 

[tarponchik]

We trust lot's of manufacturers claims but not all claims are necessary true. Sometimes they do not know themselves (I just got a recall notice on my 2004 Outback which was fine for 12 years but now it turns out the airbag can kill the passenger), sometimes they pretend they do not know (as in the Merck/Vioxx scandal) but normally we trust, until the sh@t hits the fan. Maybe in the case of oxygen analyzers it will never happen, and I certainly hope so. But most of you folks do not know how the electrochemical sensor in the O2 analyzer works, and this is truly blessing in ignorance. However, it is probably true that safety margins for O2 exposure are already tilted the way it does not matter how accurate your analyzer is and I already backed off my "borderline safety" statement.
@uncfnp If I go to Bonaire and get unlimited Nitrox, I'll spend 4-5 hrs underwater daily, so I'd keep the 1.4 limit. For a single dive a day, maybe I'll go for 1.6.