Back gases and deco gases for deep diving--split from A&I thread

[peterbj7]

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A ScubaBoard Staff Message...

The discussion below about suitable gas mixes for deep dives has been split off from this thread:
http://www.scubaboard.com/forums/accidents-incidents/428654-flintkote-mine-fatality-canada.html

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Very sad. Agreed that he could have had a hyperoxic incident. Though for that dive as described I wouldn't have used the gases he did.

 

[PfcAJ]

I would have used those exact gases, probably wouldn't have brought a stage if it was open water, though.

 

[peterbj7]

Unless I was on a CCR I wouldn't use trimix for a 200ft dive, I'd use air. My deco gases would be 32/36% (depending what's available) and 80%. I never go above 80% because it gets too problemmatical.

 

[decompression]

Unless I was on a CCR I wouldn't use trimix for a 200ft dive, I'd use air. My deco gases would be 32/36% (depending what's available) and 80%. I never go above 80% because it gets too problemmatical.

Can I ask why you'd use air as back gas and 32/36 % for deco gases?

 

[PfcAJ]

Lemme guess, air without the CCR to save a buck.

 

[Garth]

Can I ask why you'd use air as back gas and 32/36 % for deco gases?

I think he is saying 32 or 36 depending on what's available but that doesn't mean I agree with him.

Using air on a 200ft dive is stupid and not best practice any longer. One thing I'm certain of is that the person claims air is better has likely done a dive to 200ft and now he is able to post about it because he survived.

Over 80% is problematic? What the heck does that even mean.. Getting a fill beyond 2400psi? I guess.




Sent from my She-er-water Per-redator!

 

[Garth]

I've done a dive to 212 feet on air and from what I remember it was incredibly fun as well as incredibly stupid.


Sent from my She-er-water Per-redator!

 

[PfcAJ]

Using 80% is the problematic gas...

And if you can get 80%, you can get 50% and 100%. So uhh....

 

[Doppler]

... I never go above 80% because it gets too problemmatical.

OK, I'll bite.


You'll dive air to 60 metres/200 feet where the resulting PO2 is close to 1.6 bar but you never "go above" an 80 percent nitrox for deco because it's PROBLEMATICAL?

Could you explain the logic behind this piece of rocket science please?

CAN A MOD PLEASE SHIFT THIS STUFF OVER TO A DIFFERENT THREAD... THANKS

 

[ianr33]

Second Doppler's request. This is not the place for deep air bickering.