Flying after diving if computer shows all compartments cleared?

[tursiops]

just return 18 hours (DAN's repetitive dive guideline).

Unfortunately, that is just DAN-US's guideline.

 

[LFMarm]

Is it possible to calculate the benefit of O2 administration on surface for a certain amount of time? This is what I do with the leftover O2 bottle after my last dive but not sure if it’s meaningful or just a waste of time.

 

[dmaziuk]

Is it possible to calculate the benefit of O2 administration on surface for a certain amount of time? This is what I do with the leftover O2 bottle after my last dive but not sure if it’s meaningful or just a waste of time.

You can plug 0%N2 into Robert's formula referenced upthread ("theoretical diver" link) with all the attendant caveats, or you can assume that it is safe to fly when you're in the pressure group "none" and solve for the length of SI that takes you "practically there"(*).

*) Because off-gassing is a log curve that will never touch the asymptote, mathematically you can never get back to "no pressure group" if you dived even once in your lifetime.

 

[lowwall]

*) Because off-gassing is a log curve that will never touch the asymptote, mathematically you can never get back to "no pressure group" if you dived even once in your lifetime.

That must be why it feels so good to get back to depth after a long break from diving. It's all those billions of cells that never reached ambient sighing in relief.

 

[NDonahue]

Just noticed that longer dives yield a "Danger" group identifier. While that's unsurprising when pretending a multi-level dive occurred at max depth, the estimated flight time seems to ignore that dive (and is dangerously early). In such cases, it's probably best to punt and just return 18 hours (DAN's repetitive dive guideline).

Agreed. I’ll correct the ignoring of dives that throw warnings.

 

[NDonahue]

Being an old man and retired military and airline pilot, I am continually astounded there are apparently so many divers that are continually searching for that "study" that supports their willingness to risk DCS because of "get home-itis." From my perspective, a possible chamber ride or worse, is never going to be worth the cost of an extra night in a hotel and a nice relaxing dinner.

I fully agree. I just wanted to make something to help me estimate the risks for low altitude climbs in a car so I can dive each weekend and still be in the office Monday morning.

A potentially very useful improvement would be to incorporate the dive site elevation. I have seen various threads in the past from folks wondering about wait time until they can drive over a mountain pass after diving.

(FWIW, you might lengthen the dive table. I can see people trying to put in 20 dives for their vacation trip, not understanding the relative unimportance of the earliest days.)

Overall, I'd say it's a very useful and easy to use tool, especially for multiple dives. Nicely done!

will fix. Thanks for the correct way to calc bottom time for these tables.

 

[Edward3c]

I fully agree. I just wanted to make something to help me estimate the risks for low altitude climbs in a car so I can dive each weekend and still be in the office Monday morning.

That’s what we have the BSAC Altitude Change Table for, part of the BSAC level 1 to 4 88 Tables.

 

[Sascha314]

Longer dives are probably of more danger as you typically load the slower tissues more. Well still I would say better safe than sorry.


Breathing EANx with x >21 will help off gasing while at the surface for sure. You increase the partial pressure difference from your breathing gas N2 to the tissue load. How much? Well again you may calculate theoretically using e.g. Buhlmann, but its extrapolating a complex model into a regime it has never been tested thoroughly, and a model which tries to make everyone under modt circumstances safe, not taking into account your body at that time.
I would say even breathing 1h O2 after the dive I still would want to have a decent time before flying depening on the dive plane the days before.