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Date: Fri, 13 Oct 1995 16:41:58 -0700
From: saphire@ix*.ne*.co* (joan coval)
Subject: Nitrox
To: techdiver@terra.net
To: JOHNCREA@de*.co*
To: deepreef@bi*.bi*.Ha*.Or*
To: gasdive@si*.DI*.oz*.au*
To: gmiiii@in*.co*
To: cgh@ma*.ai*.mi*.ed*
To: gain@fr*.to*.on*.ca*
To: cavers@co*.ci*.uf*.ed*

Hello Mike,
	
	I have the IANTD manual Third Edition: January
1994.  I asked Tom Mount about the accuracy and
correctness of this manual about two weeks ago.  He
sluffed it off by not answering directly but instead stated
that I would get it in class, not being specific as to the
new number, if any.  Personally for $30.00 dollars that I
paid for this pamphlet, it should include an update.

	I think that a ppO2 of 1.4 ata is an order of
magnitude safer than the 1.6 ata as maximum pp02
exposure.  For Nitrox I this would give a maximum depth
of 111 fsw and for Nitrox II a maximum depth of 95 fsw.

	However, I do not agree with the partial pressure
exposure limits as presented in the NOAA Dive Manual.
There is  evidence to specifying  lower exposure limits
because of high CNS 02 toxicity probability at pp02 of 1.6
ata as well as being exposed to this oxygen partial
pressure near the 45 minute limit as specified in the
NOAA manual.  This table is table 15-1 on page 15-3 of
the October 1991 NOAA Diving Manual.

	In the U.S. Navy Divers Manual Volume  2,
Revision 3 (Mixed-Gas Diving), 15 May 1991, table 11-3
on page 11-11 shows an oxygen partial pressure
exposure limits for 1.6 ata pp02 as being 30 minutes
maximum bottom time.  In fact, the Navy considers it a
SPECIAL PROCEDURE diving with an oxygen partial
pressure greater than 1.3 ata.  I quote;  "Such dives
place the diver at increased risk for CNS oxygen toxicity
on the bottom and require NAVSEA concurrence and
CNO approval."  This is not a small or insignificant
requirement.

	In response to your comment ....... "Dangerous
yes, but (IMO) misleading only to someone who is
foolish enough to think they can use this newsgroup to
substitiute for a proper nitrox education."

	Thats pure bullshit.  This newsgroup functions as
a meeting place to exchange ideas and information from
people of varying experiences and backgrounds from
around the entire world, and this exchange is used to
enhance, REPLACE and update knowledge and to
further the contribution to the very process of learning
and awaremess and to the education of every participant.
Period.

	The truth is, that published documents, including
those that are published and/or sold by those very
agencies that certify people in nitrox training is often flat
out incorrect, and, in many cases new and substantiated
information that challenges the current copy  has been
and is continuing to be withheld.

	This CNS oxygen toxicity exposure limits were
known back in 1991 or possibly even earlier.  And if it
weren't for the Internet, and rec.scuba, and a few
individuals, you, myself and others would not be aware of
information that is NOT in agreement with established
protocols.   Interestingly enough, the best and most
tested (reliable) experience and information on mixed
gas diving does NOT come from IANTD, ANDI, TDI, and
other U.S. certifying agencies, but from commercial and
military divers.

	-Joan-

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