Nitrox & Altitude

[Wijbrandus]

I'm a certified Nitrox diver, and I'm trained in Altitude procedures. However, I took the Altitude training during my AOW, and we didn't discuss it relative to the use of Nitrox.

Are there any special considerations to using Nitrox at altitude? All of my local diving is in the neighborhood of 6000 to 10000 ft. I'm planning a few dives to 60 ffw at ~9000 ft elevation here in a few weeks, and was planning to take Nitrox tanks for the dive, but I'm not sure how that's going go.

Can I just adjust everything to EAD, and go from there? Or is there an additional consideration I need to make? For example, I can't logically see any reason that my MOD would change because of elevation, even though my theoretical depth will be different than actual depth, I just have to make sure my actual depth is shallower than my MOD.

Am I going about this right, or do I need to talk to my LDS instructor some more? My NAUI nitrox book makes no mention of altitude adjustments, and it wasn't covered in class. Everyone else was going to warm water - wussy boys.

 

[Wijbrandus]

I did another search on this, and found an old thread from 2001. It said that for dive times, pressure groups, and ascent rate to use the EOD for the altitude. For all calculations involving the FO2 of the gas, use actual depth.

The cool thing is you get a bit of a credit for lower air pressure and the fresh water weight. Not that it'll matter for my dive, just found it interesting...

I think that answers my questions, but if anyone else has something to add to the mix, please feel free to do so. I'm all ears.

 

[Don Burke]

Here is an article on the subject:

http://divermag.com/archives/dec2000/divedoctor_dec00.html

I have only waded partially through it.

 

[Wijbrandus]

Thanks for that link, Don. Parts of that article made my head hurt, but I think I got the basics of what he is saying.