divelist.c: gasmix-default translation

Lubomir I. Ivanov neolit123 at gmail.com
Fri Oct 19 08:05:00 PDT 2012

On 19 October 2012 17:31, Dirk Hohndel <dirk at hohndel.org> wrote:
> "Lubomir I. Ivanov" <neolit123 at gmail.com> writes:
> Hehe... the non-diver at work. :-)

also my grades in chemistry were't that good, if i recall... :-)

> This is totally illogical, but it's how most divers think of their
> breathing gas:
> 20.9% O2, 78.1% N2 and small amount of random other gases (ok, not
> random, but we usually ignore them). That's air. And even though it DOES
> have a distinct O2 amount, we don't list this is EAN20.9 or 20.9%
> Nitrox, we list it as air.
> Anything with a higher O2 content (and accordingly, lower N2 content) is
> listed by its O2 content: EAN32 or 32% Nitrox is very common (and
> apparently the only Nitrox level available / legal in Japan). But you
> see much higher concentration in deco gases - I've done EAN70 deco on
> one dive.
> And then, if you want to go deeper than about 50m (and yes, I know,
> crazy people go WAY deeper than that on air, but let's be real), then
> you want to REDUCE your O2 content (as it gets toxic at partial
> pressures above 1.4/1.6/2.0/whatever number you want to believe).
> AND you want to reduce the N2 content as that causes a phenomenon called
> Narcosis above a certain level. So you add He2 to the mix. And once
> again, all we list is the O2 and He2 - the rest being basically N2 is
> simply assumed.
> Does this all make more sense now?

ok, much clearer now. thanks.


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