What is the Big Deal about Nitrox??

That is the question we are frequently asked. I will attempt to answer this question. The only prerequisite to take the course is to be Open water diver certified.

WHAT IS NITROX? Nitrox is simply a mixture of oxygen and nitrogen (just like air) but has a higher % of oxygen than air. The air in the atmosphere is composed of 79% Nitrogen & 21% Oxygen. The nitrox mixtures that are commonly used are composed of 32% Oxygen and 68% Nitrogen. The other commonly used mixture is composed of 36% Oxygen and 64% Nitrogen.

What are the advantages of using Nitrox over air? The fact that there is less Nitrogen and more Oxygen significantly changes the way our bodies react to and deal with the gases. Since there is less Nitrogen in nitrox our bodies absorb less of that inert gas and our decompression obligation is less by a large margin. So, our no decompression limits are extended. Recall that when breathing an inert gas under pressure that gas will go into solution into your bodys' tissues at a rate proportional to the depth. Also recall that when you reduce the pressure (i.e. come to the surface) that inert gas which is in solution in your tissues will increase in volume and escape.

The table below shows the comparisons for no decompression limits on air, 32% and 36% nitrox:

 

NO Stop Dive Times in minutes
Depth 21% 32% 36%
Fsw AIR EAN32 EAN36
60 55 100 100
70 45 60 60
80 35 50 60
90 25 40 50
100 22 30 n/a
110 15 25 n/a
120 12 n/a n/a
130 8 n/a n/a

As you can see from this chart - Nitrox greatly adds to your bottom time

What are the disadvantages/dangers of Nitrox? The primary disadvantage of nitrox is also physiological. Oxygen is an essential gas for us to remain alive, however Oxygen breathed under too much pressure becomes toxic and can cause severe physiological problems. One of the things that can happen to a diver breathing Oxygen at too high a pressure is convulsions. When the diver convulses they will most certainly lose their regulator from their mouth and drown.

Another disadvantage is availability. Not all dive shops/boats have the ability to fill tanks with nitrox.

This sounds way too confusing to me!! The Enriched Air Diver (Nitrox) course is not a difficult one. The book requires about 4-5 hours of reading. By the end of the course the diver will be able to plan no decompression dives on any mix of Nitrox from 22% up to 40%. The diver will be able to determine the maximum and contingency depths for all the possibles mixes on nitrox from 22% up to 40% as well.

Call Jim at 352-363-0013

 

E-mail Jim@cavediveflorida.com