From: wall@hel4.brl.mil (Jeff Wall)
Newsgroups: rec.scuba
Subject: Re: Information about advanced deep diving course
Date: 3 Sep 92 14:57:23 GMT
Organization: U.S. Army Human Engineering Lab  Aberdeen, MD

In article <1992Sep2.211038.6883@odin.corp.sgi.com> mango@nova.esd.sgi.com
(Eric Manghise) writes:
>In article <1992Sep2.190620.19318@mailer.cc.fsu.edu>,
>mayne@pipe.cs.fsu.edu (William Mayne) writes:
>|> In article <1992Sep2.170103.14706@hplabsz.hpl.hp.com>
>peterson@hpl.hp.com (Chris Peterson) writes:
>|> >
>|> >	NAUI does offer a "deep diving" specialty course and, starting
>|> >	this year, a mixed gas specialty course.
>|> >...
>|> >	The Mixed Gas Diving Specialty course covers ANDI (American 
>|> >	Nitrox Diving, Inc.?) Nitrox I and Nitrox II, and the course
>|> >	instructor must have successfully completed ANDI's instructor
>|> >	course.
>|> 
>|> Say it ain't so. Calling a nitrox course "mixed gas", while technically
>|> correct (even air is mixed gas) goes against standard usage and can
>|> only add to confusion and the false idea that nitrox diving is a high
>|> tech, advanced, dangerous activity. Why don't they just call it what
>|> is, "Nitrox", like ANDI and IAND?
>
>	Well I thought we had been through this argument before. Standard
>	usage as defined by who? What book are you going by. Well Nitrox
>	diving is an advanced dangerous activity, as much as diving with
>	trimix. You can kill yourself with nitrox, I would say that makes
>	it a dangerous activity. Nitrox is a mixed gas, oxygen and nitrogen
>	so is heliox, helium and oxygen so why dont we call it what it is "Heliox".

I'd say in theory you are correct but in practice you are not corect at all. 
Diving Nitrox may take some extra training but it is nothing compared to Heliox
or trimix diving.  Nitrox is simply a different mix of nitrogen and oxygen than
air.  Air is often called "God's Nitrox."  Nitrox poses no more danger to the
diver that diving on air does, as a matter of fact I believe it is much safer
than air ever was.  Nobody ever said air was the best or safest gas to dive
with.
Sure Nitrox can kill you, but so can air for the very same reasons, plus a few
more.

>	All diving is technically mixed gas, in the circles where I dive nitrox
>	is referred to as a mixed gas, and as such the same precautions are
>	used as with mixed gas. 

In the circles I dive in its called the "good stuff" :-). No seriously, we call
NItrox Enriched Air.  I tend to classify mixed gasses as mixtures which
incorporate Helium (i.e. heliox, trimix)

>   Ie. they both require special knowledge, special
>	tables (yes I know you can use EAD), special equipment to blend the gas,
>	and in some cases special oxygen clean regulators. Remember NITROX is
>	not just 32/68 and 36/64 blends, you can custom blend it from 21/79 to
>	50/50 and beyond in special cases. I think yes we should view nitrox as
>	a mixed gas, becuase that is exactly what you are doing, blending two gases
>	together. In the case of trimix its three.

I guess when you start getting an oxygen percentage above 36% Nitrox gets a
little more hairy and special precautions are necessary.  But, Nitrox I and
Nitrox II are really no different than air with a little extra instruction. 

I can see Nitrox I and Nitrox II as a recreational gas in the next five to ten
years.  Nitrox I is good down to 130 ft ( sound familiar) a depth the agencies
are already preaching as the max depth for recreational diving.

Jeff Wall
wall@hel4.brl.mil
almost ANDI certified