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Chapter 1 Introduction 19
can nevertheless be seen as a turning point in the more
general acceptance of enriched air nitrox diving. (Two
more pre-DEMA nitrox workshops were held –1993 in
Orlando and 1994 in New Orleans.)
In 1992, NAUI officially endorsed nitrox training by
NAUI Instructors.
As late as 1993, Skin Diver Magazine took an
editorial position against the use of nitrox by recreational
divers as certain to lead to dangerous misuse and
accidents. Then, in 1994, Rodale’s Scuba Diving ran an
article on becoming nitrox certified, the first mainstream
recreational diving periodical to support nitrox training.
In 1995, PADI, British Sub-Aqua Club, and other
recreational training agencies announced that they would
soon offer enriched air nitrox instruction programs. Also
in 1995, Skin Diver Magazine declared the use of nitrox
acceptable.
In 1996, NAUI codified standards for Enriched Air
Nitrox training and certification in its revised NAUI
Standards and Policies Manual. Shortly thereafter, NAUI
published the first nitrox training textbook from a
mainstream recreational dive training agency.
Today, enriched air nitrox has become a viable and
valued part of recreational diving (Figure 1-6), and
“nitrox fills” are available to qualified divers at diving
destinations around the world (Figure 1-7). In this text
and in your NAUI Nitrox training course you will learn
the facts about enriched air nitrox and how to use it
safely.
Figure 1-7 "Nitrox fills" are available to qualified
divers at diving destinations around the
world.
WHY DIVE WITH ENRICHED AIR
NITROX?
From the preceding, you should have gained an
appreciation of nitrox and some of the benefits of its use
in diving. Without going into great detail, we’ll note a few
of them. You will gain a greater appreciation of both the
benefits and the necessary precautions as you learn more
about diving with oxygen-enriched air.
First and most notably, nitrox allows divers to extend
their bottom time and enjoy longer dives without having
a required-decompression obligation.
For example, a diver making an initial dive to 27
meters (90 feet) using air would have a maximum dive
time of 25 minutes on the NAUI Dive Tables. The same
diver using a nitrox mix with 36% oxygen (EAN36)
would have a maximum dive time of 40 minutes on the
NAUI EAN36 Dive Tables. Using the NAUI Reduced
Gradient Bubble Model (RGBM) Tables, the diver would
have 25 minutes if using air and 46 minutes if using
EAN36.
Nitrox has advantages in repetitive dives. Looking at
a typical recreational dive profile, let’s compare a series of
two dives: one diver is breathing air, and the other diver
is breathing EAN36. The first dive is to 24 meters (80
feet) for 30 minutes. After a one-hour surface interval, the
second dive will be to 16 meters (53 feet) (Figure 1-8).
Diver one, using air and NAUI Dive Tables, emerges
from the first dive with a Letter Group of H. One hour
later, entering the water as an “G diver,” the diver has
an adjusted maximum dive time of 10 minutes for the
16-meter (53-foot) dive. If the diver is using the NAUI
Figure 1-6 Today, enriched air nitrox has become
a viable and valued part of recreational
diving.