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PADI ENRICHED AIR DIVER EXAM STUDY GUIDE
EXAM LATEST UPDATE THIS YEAR ALL WITH
180 QUESTIONS AND CORRECT DETAILED
ANSWERS
Question: The primary concern regarding enriched air nitrox and equipment is high oxygen
content. - CORRECT ANSWER✔✔The primary concern regarding nitrox is the high oxygen
content because some materials more readily burn, or even explode, in the presence of oxygen.
Question: The recommendations for using equipment, other than cylinders, with enriched air
with up to 40% oxygen, include that (choose all that apply) - CORRECT ANSWER✔✔Generally,
for all equipment except your cylinder you can use regular scuba equipment with enriched air
with up to 40% oxygen. However, local laws, standards or practices may require special fittings
or cleanings; follow these if they apply. In any case, during servicing, oxygen compatible
lubricants, as well as other materials, are generally recommended.
Question: The potential hazards of improper enriched air filling procedures include (choose all
that apply) - CORRECT ANSWER✔✔The primary hazards are fire or explosion hazard due to high
oxygen content coming in contact with combustible substances, and inaccuracies in the blend
leading to uncertainty of what the final blend is. Nothing about blending would affect the
potential for narcosis, nor likely affect the reliability of a scuba regulator.
Question: The primary benefit of using enriched air nitrox is that it - CORRECT ANSWER✔✔The
primary benefit of using enriched air is longer no stop (no decompression) dive times. It is not a
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suitable deep diving gas due to oxygen exposure, and there is no substantiated evidence that it
makes you feel better.
Question: When using EANx, you should expect narcosis to be - CORRECT ANSWER✔✔Although
enriched air has less nitrogen than air does, oxygen has been shown to be about as narcotic as
nitrogen. Therefore, you should expect little difference between diving nitrox and air with
respect to narcosis.
Question: The markings that, according to broadly accepted dive community practices, you
should have on a scuba cylinder used for enriched air nitrox include (choose all that apply) -
CORRECT ANSWER✔✔The minimum markings on an enriched air cylinder include all the
markings required of an air cylinder, plus a band around the cylinder shoulder reading NITROX,
ENRICHED AIR or the like. Yellow cylinders should have a 10 centimetre/4 inch green band. Non
yellow cylinders should have a 15 centimetre/6 inch band. The top and bottom of this band
should be a yellow, 2.5 cm/1 in. band, with the center 10 cm/4 in of green. There should also be
a sticker/decal indicating whether or not the cylinder is oxygen service rated, and a tag or
sticker with the diver's name, the EANx blend, fill date and the maximum depth for using the
blend. Local laws or standards may also add or substitute required markings. The blender's
name, initials or the boat name may be on the cylinder, but these are not considered required
markings.
Question: The maximum oxygen partial pressure is _____________ and contingency partial
pressure is ________________. - CORRECT ANSWER✔✔The maximum oxygen partial pressure
for a given blend is 1.4 ata/bar. The contingency maximum is 1.6 ata/bar. It's important to
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remember these limits because they're the basis of the maximum depth of each EANx blend.
The higher the oxygen content, the shallower the depth at which you reach 1.4 ata/bar.
Question: The primary hazard of exceeding oxygen limits is having a _________________ which
is likely to lead to ______________ underwater. - CORRECT ANSWER✔✔The primary hazard of
exceeding oxygen limits is having a CNS (central nervous system) convulsion. The convulsion is
not usually fatal itself, but if it happens underwater, is likely to lead to drowning. It is easy to
stay within oxygen limits, but you should take them seriously.
Question: To avoid the primary hazard of exceeding oxygen exposure limits (choose all that
apply) - CORRECT ANSWER✔✔To avoid risk of having a convulsion and drowning due to oxygen
toxicity, always stay well within your dive computer's oxygen exposure limits. Stay shallower
than the maximum depth of the blend you're using. You should not exceed an oxygen partial
pressure of 1.4 ata/bar.
Question: Signs and symptoms always precede a CNS convulsion. - CORRECT ANSWER✔✔False
- Signs and symptoms may precede a CNS convulsion, but they usually do not.
Question: Signs and symptoms that indicate a diver may convulse due to oxygen toxicity include
(choose all that apply) - CORRECT ANSWER✔✔Limb and joint pain is a sign/symptom of
decompression sickness, not oxygen toxicity. All the others are signs/symptoms of oxygen
toxicity, which you can remember with VENTID - Visual disturbances; Ear ringing; Nausea;
Twitching; Irritability; anxiety and euphoria; and Dizziness.
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Question: When using an EANx compatible dive computer to manage oxygen, you should
(choose all that apply) - CORRECT ANSWER✔✔Set the maximum oxygen partial pressure for 1.4
(1.6 is the contingency limit) and set the computer for the blend you're using. With most
models, the deepest depth displayed when you scroll the no stop limits is the maximum depth.
You should watch the depth as your primary means of staying shallower than this depth - use
the computer's warning as a secondary alert. Stay well within the computer's oxygen exposure
limits. It's generally recommended that you allow at least an hour between nitrox dives to help
stay well within oxygen exposure limits. Always follow the manufacturer's guidelines regarding
settings and displays.
Question: What should you do if you accidentally exceed the oxygen limits of your computer?
(Choose all that apply.) - CORRECT ANSWER✔✔If you exceed any oxygen limit of your computer,
you should end the dive immediately. Ascend, make a safety stop and surface. You should not
dive for at least 24 hours, or for the minimum interval recommended by the computer
manufacturer. Once you've surfaced and exited the water, the risk of oxygen toxicity drops to
almost none (and the potential consequences are far less severe since you're no longer in the
water anyway), so there's no need to contact emergency medical care.
Question: Who must personally verify the oxygen analysis of a cylinder of enriched air? -
CORRECT ANSWER✔✔The diver who will use an enriched air cylinder must personally verify the
analysis of the cylinder contents, without exception. The divemaster and/or the diver's buddy
may also verify the cylinder contents, but doing so is not considered mandatory in all
circumstances.
Question: What is the first step you do when analyzing an enriched air blend? - CORRECT
ANSWER✔✔The steps are: 1) Attach the analyzer to a flow restrictor or flow meter supplying air
PADI ENRICHED AIR DIVER EXAM STUDY GUIDE
EXAM LATEST UPDATE THIS YEAR ALL WITH
180 QUESTIONS AND CORRECT DETAILED
ANSWERS
Question: The primary concern regarding enriched air nitrox and equipment is high oxygen
content. - CORRECT ANSWER✔✔The primary concern regarding nitrox is the high oxygen
content because some materials more readily burn, or even explode, in the presence of oxygen.
Question: The recommendations for using equipment, other than cylinders, with enriched air
with up to 40% oxygen, include that (choose all that apply) - CORRECT ANSWER✔✔Generally,
for all equipment except your cylinder you can use regular scuba equipment with enriched air
with up to 40% oxygen. However, local laws, standards or practices may require special fittings
or cleanings; follow these if they apply. In any case, during servicing, oxygen compatible
lubricants, as well as other materials, are generally recommended.
Question: The potential hazards of improper enriched air filling procedures include (choose all
that apply) - CORRECT ANSWER✔✔The primary hazards are fire or explosion hazard due to high
oxygen content coming in contact with combustible substances, and inaccuracies in the blend
leading to uncertainty of what the final blend is. Nothing about blending would affect the
potential for narcosis, nor likely affect the reliability of a scuba regulator.
Question: The primary benefit of using enriched air nitrox is that it - CORRECT ANSWER✔✔The
primary benefit of using enriched air is longer no stop (no decompression) dive times. It is not a
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suitable deep diving gas due to oxygen exposure, and there is no substantiated evidence that it
makes you feel better.
Question: When using EANx, you should expect narcosis to be - CORRECT ANSWER✔✔Although
enriched air has less nitrogen than air does, oxygen has been shown to be about as narcotic as
nitrogen. Therefore, you should expect little difference between diving nitrox and air with
respect to narcosis.
Question: The markings that, according to broadly accepted dive community practices, you
should have on a scuba cylinder used for enriched air nitrox include (choose all that apply) -
CORRECT ANSWER✔✔The minimum markings on an enriched air cylinder include all the
markings required of an air cylinder, plus a band around the cylinder shoulder reading NITROX,
ENRICHED AIR or the like. Yellow cylinders should have a 10 centimetre/4 inch green band. Non
yellow cylinders should have a 15 centimetre/6 inch band. The top and bottom of this band
should be a yellow, 2.5 cm/1 in. band, with the center 10 cm/4 in of green. There should also be
a sticker/decal indicating whether or not the cylinder is oxygen service rated, and a tag or
sticker with the diver's name, the EANx blend, fill date and the maximum depth for using the
blend. Local laws or standards may also add or substitute required markings. The blender's
name, initials or the boat name may be on the cylinder, but these are not considered required
markings.
Question: The maximum oxygen partial pressure is _____________ and contingency partial
pressure is ________________. - CORRECT ANSWER✔✔The maximum oxygen partial pressure
for a given blend is 1.4 ata/bar. The contingency maximum is 1.6 ata/bar. It's important to
, Page 3 of 33
remember these limits because they're the basis of the maximum depth of each EANx blend.
The higher the oxygen content, the shallower the depth at which you reach 1.4 ata/bar.
Question: The primary hazard of exceeding oxygen limits is having a _________________ which
is likely to lead to ______________ underwater. - CORRECT ANSWER✔✔The primary hazard of
exceeding oxygen limits is having a CNS (central nervous system) convulsion. The convulsion is
not usually fatal itself, but if it happens underwater, is likely to lead to drowning. It is easy to
stay within oxygen limits, but you should take them seriously.
Question: To avoid the primary hazard of exceeding oxygen exposure limits (choose all that
apply) - CORRECT ANSWER✔✔To avoid risk of having a convulsion and drowning due to oxygen
toxicity, always stay well within your dive computer's oxygen exposure limits. Stay shallower
than the maximum depth of the blend you're using. You should not exceed an oxygen partial
pressure of 1.4 ata/bar.
Question: Signs and symptoms always precede a CNS convulsion. - CORRECT ANSWER✔✔False
- Signs and symptoms may precede a CNS convulsion, but they usually do not.
Question: Signs and symptoms that indicate a diver may convulse due to oxygen toxicity include
(choose all that apply) - CORRECT ANSWER✔✔Limb and joint pain is a sign/symptom of
decompression sickness, not oxygen toxicity. All the others are signs/symptoms of oxygen
toxicity, which you can remember with VENTID - Visual disturbances; Ear ringing; Nausea;
Twitching; Irritability; anxiety and euphoria; and Dizziness.
, Page 4 of 33
Question: When using an EANx compatible dive computer to manage oxygen, you should
(choose all that apply) - CORRECT ANSWER✔✔Set the maximum oxygen partial pressure for 1.4
(1.6 is the contingency limit) and set the computer for the blend you're using. With most
models, the deepest depth displayed when you scroll the no stop limits is the maximum depth.
You should watch the depth as your primary means of staying shallower than this depth - use
the computer's warning as a secondary alert. Stay well within the computer's oxygen exposure
limits. It's generally recommended that you allow at least an hour between nitrox dives to help
stay well within oxygen exposure limits. Always follow the manufacturer's guidelines regarding
settings and displays.
Question: What should you do if you accidentally exceed the oxygen limits of your computer?
(Choose all that apply.) - CORRECT ANSWER✔✔If you exceed any oxygen limit of your computer,
you should end the dive immediately. Ascend, make a safety stop and surface. You should not
dive for at least 24 hours, or for the minimum interval recommended by the computer
manufacturer. Once you've surfaced and exited the water, the risk of oxygen toxicity drops to
almost none (and the potential consequences are far less severe since you're no longer in the
water anyway), so there's no need to contact emergency medical care.
Question: Who must personally verify the oxygen analysis of a cylinder of enriched air? -
CORRECT ANSWER✔✔The diver who will use an enriched air cylinder must personally verify the
analysis of the cylinder contents, without exception. The divemaster and/or the diver's buddy
may also verify the cylinder contents, but doing so is not considered mandatory in all
circumstances.
Question: What is the first step you do when analyzing an enriched air blend? - CORRECT
ANSWER✔✔The steps are: 1) Attach the analyzer to a flow restrictor or flow meter supplying air
