PADI - ENRICHED AIR DIVER REVIEW
CORRECT 100%
The primary benefit of using enriched air nitrox is that it - ANSWER The primary benefit
of using enriched air is longer no stop (no decompression) dive times. It is not a suitable
deep diving gas due to oxygen exposure, and there is no substantiated evidence that it
makes you feel better.
When using EANx, you should expect narcosis to be - 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.
The primary concern regarding enriched air nitrox and equipment is high oxygen
content. - 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.
The recommendations for using equipment, other than cylinders, with enriched air with
up to 40% oxygen, include that (choose all that apply) - 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.
The potential hazards of improper enriched air filling procedures include (choose all that
apply) - 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.
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) -
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.
, The maximum oxygen partial pressure is _____________ and contingency partial
pressure is ________________. - 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
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.
The primary hazard of exceeding oxygen limits is having a _________________ which
is likely to lead to ______________ underwater. - 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.
To avoid the primary hazard of exceeding oxygen exposure limits (choose all that apply)
- 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.
Signs and symptoms always precede a CNS convulsion. - ANSWER False - Signs and
symptoms may precede a CNS convulsion, but they usually do not.
Signs and symptoms that indicate a diver may convulse due to oxygen toxicity include
(choose all that apply) - 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.
What should you do if your enriched air computer fails during a dive? (Choose all that
apply.) - ANSWER Dive computer failure is very rare, but should it happen and you're
diving well within its limits, you will remain within limits by immediately ascending,
making a safety stop and surfacing. Unless you have a backup computer, you need to
let residual nitrogen clear from your body before resuming diving with another computer.
For that reason, you don't dive again for at least 12 hours, or longer if specified by the
computer manufacturer. Because dive computers track your dive profile closely, you
don't attempt to share your buddy's computer - especially if your buddy's using a
different EANx blend. Assuming you have no symptoms of decompression illness, there
is no need to breathe emergency oxygen after the dive.
If a diver convulses underwater, your priority is to get the diver to the surface. Treat the
diver as an unresponsive diver. - ANSWER If a diver convulses underwater, your
priority is to get the diver to the surface. Treat the diver as an unresponsive diver. Hold
the mouthpiece in if it's in the mouth, but don't waste time trying to replace it if it's not.
Take the victim to the surface, establish ample buoyancy, check for breathing and call
for help. Provide rescue breaths if the victim isn't breathing. Get the victim to the boat or
shore and check for a pulse and breathing. Provide CPR as necessary while waiting for
CORRECT 100%
The primary benefit of using enriched air nitrox is that it - ANSWER The primary benefit
of using enriched air is longer no stop (no decompression) dive times. It is not a suitable
deep diving gas due to oxygen exposure, and there is no substantiated evidence that it
makes you feel better.
When using EANx, you should expect narcosis to be - 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.
The primary concern regarding enriched air nitrox and equipment is high oxygen
content. - 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.
The recommendations for using equipment, other than cylinders, with enriched air with
up to 40% oxygen, include that (choose all that apply) - 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.
The potential hazards of improper enriched air filling procedures include (choose all that
apply) - 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.
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) -
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.
, The maximum oxygen partial pressure is _____________ and contingency partial
pressure is ________________. - 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
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.
The primary hazard of exceeding oxygen limits is having a _________________ which
is likely to lead to ______________ underwater. - 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.
To avoid the primary hazard of exceeding oxygen exposure limits (choose all that apply)
- 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.
Signs and symptoms always precede a CNS convulsion. - ANSWER False - Signs and
symptoms may precede a CNS convulsion, but they usually do not.
Signs and symptoms that indicate a diver may convulse due to oxygen toxicity include
(choose all that apply) - 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.
What should you do if your enriched air computer fails during a dive? (Choose all that
apply.) - ANSWER Dive computer failure is very rare, but should it happen and you're
diving well within its limits, you will remain within limits by immediately ascending,
making a safety stop and surfacing. Unless you have a backup computer, you need to
let residual nitrogen clear from your body before resuming diving with another computer.
For that reason, you don't dive again for at least 12 hours, or longer if specified by the
computer manufacturer. Because dive computers track your dive profile closely, you
don't attempt to share your buddy's computer - especially if your buddy's using a
different EANx blend. Assuming you have no symptoms of decompression illness, there
is no need to breathe emergency oxygen after the dive.
If a diver convulses underwater, your priority is to get the diver to the surface. Treat the
diver as an unresponsive diver. - ANSWER If a diver convulses underwater, your
priority is to get the diver to the surface. Treat the diver as an unresponsive diver. Hold
the mouthpiece in if it's in the mouth, but don't waste time trying to replace it if it's not.
Take the victim to the surface, establish ample buoyancy, check for breathing and call
for help. Provide rescue breaths if the victim isn't breathing. Get the victim to the boat or
shore and check for a pulse and breathing. Provide CPR as necessary while waiting for
