Is nitrox "briefing" enough without certification?

[Snakekid97]

Hi all,

I have a basic OW certificate with about a dozen OW dives. I recently moved to a coastline, but I haven't gone diving in the ocean in about a year (although I have done a couple of quarry dives since). I recently talked to a local PADI instructor/dive charter owner about easing back into things. After scheduling a date to go out on his charter, I found out they only use nitrox on all of their dives. They claim it's the better way to dive. Their website states " If you are not Nitrox certified, don’t worry, we will give you a Nitrox Briefing that lets you dive Nitrox that day...We will also put a _ Dive Computer on your wrist set for 32% so you can track your NDL."

I have read that I should have a certification for nitrox (which I don't have). My question is: would you trust a "Nitrox briefing that lets you dive Nitrox that day" or does this seem to be a questionable practice? I have no prior experience with Nitrox.

I should add, the charter is a 2-tank trip on reefs 40-60' deep over about a 3-hour period.

Thanks!

 

[wetb4igetinthewater]

I get that it is GAS narcosis, but is it based on what's coming in/out of the lungs in real time or does it depend on body accumulation? Hopefully, that makes sense. Reason I ask is because if it is heavily accumulation dependent, than it seems the N2% would matter since O2 metabolizes. I have never been narc'd but I guess the easiest answer to my question would be if a person is susceptible to this, are they immediately susceptible if they go straight to depth or does it get worse if they stay there? Again, hope that made sense

Remember we breath in 21% oxygen when breathing air, and exhale 16%. So let's just say we have 3/4 of the oxygen going out than going in. Per the table above with a relative narcotic effect, the consumed oxygen is replaced by even more narcotic CO2.

 

[scubadada]

I have in the past referenced a story I got from )IIRC) Bob Bailey, who used to go by NWgratefuldiver but has since moved to Mexico. In his version, when denied nitrox with a trimix card, he asked for a trimix fill of 32/0, and he was successful in making the guy realize the inanity of it all.

Still very much around @MXGratefulDiver

 

[boulderjohn]

Link? Peer reviewed?

I am currently inFiji with limited time allowed on the Internet. This has appeared in a number of threads in the past. It was first introduced to ScubaBoard by Simon Mitchell.

 

[wetb4igetinthewater]

I am currently inFiji with limited time allowed on the Internet. This has appeared in a number of threads in the past. It was first introduced to ScubaBoard by Simon Mitchell.

Please post whenever you get the chance. Thanks.

 

[RobPNW]

Remember we breath in 21% oxygen when breathing air, and exhale 16%. So let's just say we have 3/4 of the oxygen going out than going in. Per the table above with a relative narcotic effect, the consumed oxygen is replaced by even more narcotic CO2.

But CO2 is only produced when O2 is metabolized right? So, unless your work load increases significantly, the amount of CO2 created wouldn't rise significantly correct?

 

[boulderjohn]

Link? Peer reviewed?

Here is one post quoting Simon Mitchell.

Oxygen narcotic?

EAN32 is more narcotic than air. Oxygen is more narcotic than nitrogen. Choosing EAN32 to reduce narcosis will not work. Splitting this off from another thread because of curiosity. I'm in the middle of doing a TDI trimix class, because helium! But one of the slides in the powerpoint we were...

scubaboard.com

 

[JoeTPhilly]

Is Oxygen Narcosis A Thing?

There’s been a long running debate as to whether oxygen is a narcotic diving gas. Training agencies CMAS, GUE, PADI and PSAI include O2 in their equivalent narcotic depth (END) calculations. Others like BSAC, IANTD, NAUI and TDI do not. The problem has been reliably measuring gas narcosis. Enter...

gue.com

 

[Angelo Farina]

Narcosis hits quickly. The faster you descend, the worst the hit.
It increases with exposure time, but not so much.
And if you just ascend 10 meters (1 bar), the narcosis fades away almost instaneously.
And then you can often descend again, with a much lesser narcosis.
I have been narched several times at the beginning of my career, always on air, at depths ranging between 40 and 60 m.
It can be quite pleasant...

 

[Angelo Farina]

Remember we breath in 21% oxygen when breathing air, and exhale 16%. So let's just say we have 3/4 of the oxygen going out than going in. Per the table above with a relative narcotic effect, the consumed oxygen is replaced by even more narcotic CO2.

In fact if you vent improperly ("breath normally" as per Padi recommendations) you get a much worst narcosis, than breathing deep, slow and with inspiratory pause, so that much less CO2 is accumulated, as thaught in CMAS courses.

 

[scubadada]

...I have been narched several times at the beginning of my career, always on air, at depths ranging between 40 and 60 m.
It can be quite pleasant...

I have always wondered if the experience of narcosis while diving is somewhat dependent on previous encounters with the feelings and alterations.