Quiz - Skills & Environment - Diving at Altitude

[EFX]

This should be an uncontroversial question

Oh, I hope not. If so, I'll have to throw my popcorn out.

 

[tursiops]

I believe there are special tables for altitudes above a certain level (1,000' I believe). True?

You may be thinking of the tables to help you determine theoretical depth...but once you have that, you use your regular NDL tables.

 

[Pedro Burrito]

Spoiler: Answer

d. all of the above are correct.

 

[TMHeimer]

You may be thinking of the tables to help you determine theoretical depth...but once you have that, you use your regular NDL tables.

Yeah, that's what I recall reading. So what do you do with these tables that help determine theoretical depth? Do you use them alongside the RDP as you do with the nitrox tables? What do these theoretical depth tables look like? I've never seen one.

 

[tursiops]

Yeah, that's what I recall reading. So what do you do with these tables that help determine theoretical depth? Do you use them alongside the RDP as you do with the nitrox tables? What do these theoretical depth tables look like? I've never seen one.

Here's an example.

 

[TMHeimer]

Thanks. Should've just looked in my old Adventures in Diving manual and there it was.

 

[BRT]

Why would nitrogen narcosis happen at shallower depths at altitude?

 

[Vitesse2l]

Why would nitrogen narcosis happen at shallower depths at altitude?

That was my thought also. Something to do with reduced air pressure before the dive? Don't know.

 

[Edward3c]

I believe there are special tables for altitudes above a certain level (1,000' I believe). True?

BSAC have altitude tables with 4 levels to 3,000m, see here.

 

[NAM001]

In general most questions do not have an all of the above unless that is the answer but I am with those wondering about he narcosis answer. Is not narcosis driven by hard presure and that PPN2 is related to sea level as a standard? Then since you have a lower ambient you would have to go deeper. Based on the answer It would say that narcosis is the same PPN2 but based on the shore ambient pressure of the higher altitude as opposed to sea level. Puzzeling to me because if at sea level it takes say 4 atmospheres to begin to have it which would be 100 ft does that mean if the ambient is now say .8 of sea level atmosphere it will not occur at say 70 ft or 4 times the .8 atmosphere. If that is true then it must be the body adjusting from the surface pressure to the water pressure making a 4 atm change the key. That would make me wonder if the body would first have to be adapted for high altitude over some period of time rather than a quick trip from the beech to a high altitude for the body to function in that altitude as a norm. . Does the body acclimate that fast to altitude change? Then if not so someone that lives in high altitude is already on their way to the narcosis PPN2 by nothing more than the drive to the beech. Would that body be experiencing a PPN2 of something like 1.3 atmospheres going form a .8 altitude compares to sea level to sea level simply by gong to the beech. Sports people do not adapt immediately to playing in higher altitudes. and those in say denver going to san diego to play a game get an advantage from the lower altitude and thicker air.

Great question for thought