6
74 NAUI Nitrox Diver
delivering nitrox is popular in remote locations, on liveaboard
dive boats, and in other places where oxygen is
not readily obtained or is very expensive.
YOUR RESPONSIBILITY
As a nitrox diver, you are responsible not only for your
dive planning and execution but also for your equipment.
You should keep your gear well maintained, be careful
in its use, and keep it clean. Your cylinder will be a
dedicated nitrox cylinder, and although sometimes it
may be filled with air (EAN21 as some call it), you should
obtain your air only from a fill station with a compressor
that supplies nitrox-compatible grade air. Another air
source could possibly deliver air that would contaminate
your cylinder for future partial-pressure blending.
Your responsibility for your breathing gas does not
end with keeping your equipment clean and obtaining
your oxygen-enriched air from someone whom you
trust. A unique feature of nitrox diving is that the enduser
is responsible for the correctness of what he or she
will breathe (Figure 6-7). You are responsible for your
cylinder’s contents being what you asked for. A final step
before you take the cylinder away with you is verifying
the contents. The next chapter will discuss this last step –
analyzing your gas and correctly labeling your cylinder.
Verify What You Have Learned
Review the following questions about
Oxygen Precautions and Preparing Nitrox:
1. In order for a fire to occur, what three things must
be present?
2. All equipment to be used with pure oxygen must
be _____ and _____ parts must be used in order to
minimize risk of fire or destruction by the oxygen.
3. What does oxygen compatible mean?
4. The general rule of thumb is that any equipment that
is to be used with pure oxygen or an oxygen level
that is above _____ must be cleaned for oxygen
service and have only oxygen-compatible parts.
5. What must be done to a cylinder after being cleaned
for use with oxygen-enriched air?
6. Describe the common identification labeling for a
nitrox cylinder.
7. Why must cylinders be prepared for designated
nitrox service?
8. Describe what a blending technician does during
partial-pressure mixing.
9. Describe the continuous-flow method.
10. Pressure swing absorption (PSA) uses a material
called _____ that _____ from the air that passes over
or through it.
11. Membrane separation uses a _____ that allows _____
to flow through it more readily than _____.
For answers, see Appendix.
Figure 6-7 A unique feature of nitrox diving is
that the end-user is responsible for the
correctness of what he or she will breathe.