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22 NAUI Nitrox Diver
Pioneers Paving the Way
Throughout diving’s history, it is NAUI leaders,
pioneers and trend setters who have defined the
sport. Whether in the establishment of scuba
instructional standards, equipment development,
advancements in underwater research or dive
training innovations, NAUI pioneers have paved
the way for divers around the world.
Dr. J. Morgan Wells (1940-2017)
Dr. J. Morgan Wells received scientific diving
training at Scripps Institution of Oceanography
(University of California) in 1962. In 1965, he
became a U.S. Navy SEALAB Aquanaut and
received mixed-gas and rebreather training from
the U.S. Navy Mine Defense Lab.
For over 24 years, Wells was employed
by the National Oceanic and Atmospheric
Administration (NOAA), serving as science
coordinator for the Manned Undersea Science
and Technology Office. He was appointed
director of the NOAA Diving Program in
1978, teaching advanced training courses in
hyperbaric medicine after recognizing that
physicians had little training. In 1989, he
achieved the career-long ambition of creating
the NOAA Experimental Diving Unit. He also
developed the use of nitrox dive standards,
now known as NOAA Nitrox I (1978) and NOAA
Nitrox II (1990).
Wells worked tirelessly to improve the dive
industry and NAUI. In recognition of his lifelong
commitment and dedication to diving, Wells was
inducted into the 2016 NAUI Hall of Honor and
was granted the NAUI Lifetime Achievement
Award in 2017, in addition to other honors.
A glossary is included at the end of the book where you
can look up definitions of unfamiliar terms.
Enriched air nitrox, nitrox, oxygen-enriched air, and
EANx are used interchangeably throughout this text.
Where applicable, the “x” may be replaced by the oxygen
percentage (e.g. EAN36). In your reading else-where, you
will also see references to NOAA Nitrox I and NOAA
Nitrox II. These terms refer to EAN32 and EAN36
respectively, and NOAA is currently trying to change its
terminology to NN32 and NN36.
The amount of a component gas in a mixture may
be expressed as a percentage or a fraction. A percentage
compares the quantity of the component gas to a total of
100; a fraction compares it to one. EAN36 can be said to
be 36% oxygen and 64% nitrogen, or it can be said that
the fraction of oxygen is 0.36 and that of nitrogen is 0.64.
In formulas and calculations, the gas component is always
expressed as a fraction.
It is best to not use terminology in which the
components are unspecified. Terms like “60-40 mix” are
ambiguous. This is particularly so because in some usages
it is customary to state the oxygen first, and in others to
state the inert gas first. If the meaning is not specified,
either number could refer to the oxygen content, and
getting it wrong could have disastrous results.
Welcome to the world of nitrox diving! Dive safely.
This book will give you tools and techniques to extend
your enjoyment of the underwater world.
Verify What You Have Learned
Review the following questions about
Introduction to Nitrox:
1. The nitrogen in the air you are breathing limits what?
2. What are the several names given to the gas mixture
that is higher in oxygen and lower in nitrogen?
3. When diving, what causes the additional nitrogen to
be dissolved in our tissues?
4. In 1878, Paul Bert established that nitrogen, liberated
as bubbles following sudden decompression, was
the cause of what?
5. Credit for developing and introducing nitrox diving
techniques for standard scuba goes to whom?
6. In what year did NAUI officially endorse nitrox
training by NAUI Instructors?
7. List 4 advantages of using nitrox.
8. Nitrox provides the greatest advantages for dives in
what depth range?
9. The “x” in EANx is often replaced with what?
10. What compares the quantity of the conponent gas to
a total of 100? What compares it to 1?
For answers, see Appendix.