SSI Enriched Air Nitrox Questions &
Correct Answers(RATED A)
When oxygen becomes toxic to body tissues, it most noticeably and immediately affects
the:
Bones and blood
Lungs and central nervous system
Central nervous system and feet
Lungs and circulation system - ANSWER Lungs and central nervous system
How is the ppO2 of a breathing gas calculated?
Multiply cylinder pressure by the fraction of nitrogen (FN2) in the cylinder
Multiplying ambient pressure by the fraction of oxygen (FO2) in the breathing gas
Dividing ambient pressure by the fraction of oxygen (FO2) in the breathing gas
Multiplying air pressure by the fraction of oxygen (FO2) in the breathing gas - ANSWER
Multiplying ambient pressure by the fraction of oxygen (FO2) in the breathing gas
What does ppO2 mean?
Nitrox
Air
Partial pressure of oxygen
Partial pressure of nitrogen - ANSWER Partial pressure of oxygen
The threshold for CNS oxygen toxicity appears to be at a ppO2 of:
1.4 ata
1.6 ata
1.1 ata
32% - ANSWER 1.1 ata
The risk of CNS Oxygen Toxicity becomes more substantial above:
A ppO2 of 1.6 ata
A dive time of 30 minutes with air at 66 feet
A ppO2 of 1.4 ata
1000 feet of altitude - ANSWER A ppO2 of 1.6 ata
Pulmonary Oxygen Toxicity (the Lorrain Smith Effect) poses no real risk to recreational
divers because:
Pulmonary Oxygen Toxicity does not lead to problems.
, The required exposure time before symptoms arise is well below the duration of most
sport dives
The risk of Pulmonary Oxygen Toxicity becomes more substantial on a single short dive
above a ppO2 of 1.6 ata
A common misconception is that, when compared to air, nitrox enables divers to dive:
longer
shallower
shorter
deeper - ANSWER deeper
While diving nitrox, you can improve your safety by:
Using helium computers
Using the no-decompression limits of an air computer or air tables
Using nitrox tables
Using nitrox computers set to nitrox - ANSWER Using the no-decompression limits of
an air computer or air tables
The two most commonly used nitrox mixtures in recreational diving are:
EAN32/EAN36
EAN80/EAN20
EAN50/EAN60
EAN21/EAN79 - ANSWER EAN32/EAN36
Nitrox and the acronym EANx refer to mixtures with oxygen concentrations (FO2) higher
than:
40%
36%
32%
21% - ANSWER 21%
Which special skills are required before you dive with nitrox?
None
Ability to carry up to two cylinders
Correct analysis of cylinder contents in the field and at the blending station
Buddy breathing - ANSWER Correct analysis of cylinder contents in the field and at the
blending station
If there is any doubt about the O2 rating of the cylinder it should:
Be handled as oxygen rated
Never be filled again
Correct Answers(RATED A)
When oxygen becomes toxic to body tissues, it most noticeably and immediately affects
the:
Bones and blood
Lungs and central nervous system
Central nervous system and feet
Lungs and circulation system - ANSWER Lungs and central nervous system
How is the ppO2 of a breathing gas calculated?
Multiply cylinder pressure by the fraction of nitrogen (FN2) in the cylinder
Multiplying ambient pressure by the fraction of oxygen (FO2) in the breathing gas
Dividing ambient pressure by the fraction of oxygen (FO2) in the breathing gas
Multiplying air pressure by the fraction of oxygen (FO2) in the breathing gas - ANSWER
Multiplying ambient pressure by the fraction of oxygen (FO2) in the breathing gas
What does ppO2 mean?
Nitrox
Air
Partial pressure of oxygen
Partial pressure of nitrogen - ANSWER Partial pressure of oxygen
The threshold for CNS oxygen toxicity appears to be at a ppO2 of:
1.4 ata
1.6 ata
1.1 ata
32% - ANSWER 1.1 ata
The risk of CNS Oxygen Toxicity becomes more substantial above:
A ppO2 of 1.6 ata
A dive time of 30 minutes with air at 66 feet
A ppO2 of 1.4 ata
1000 feet of altitude - ANSWER A ppO2 of 1.6 ata
Pulmonary Oxygen Toxicity (the Lorrain Smith Effect) poses no real risk to recreational
divers because:
Pulmonary Oxygen Toxicity does not lead to problems.
, The required exposure time before symptoms arise is well below the duration of most
sport dives
The risk of Pulmonary Oxygen Toxicity becomes more substantial on a single short dive
above a ppO2 of 1.6 ata
A common misconception is that, when compared to air, nitrox enables divers to dive:
longer
shallower
shorter
deeper - ANSWER deeper
While diving nitrox, you can improve your safety by:
Using helium computers
Using the no-decompression limits of an air computer or air tables
Using nitrox tables
Using nitrox computers set to nitrox - ANSWER Using the no-decompression limits of
an air computer or air tables
The two most commonly used nitrox mixtures in recreational diving are:
EAN32/EAN36
EAN80/EAN20
EAN50/EAN60
EAN21/EAN79 - ANSWER EAN32/EAN36
Nitrox and the acronym EANx refer to mixtures with oxygen concentrations (FO2) higher
than:
40%
36%
32%
21% - ANSWER 21%
Which special skills are required before you dive with nitrox?
None
Ability to carry up to two cylinders
Correct analysis of cylinder contents in the field and at the blending station
Buddy breathing - ANSWER Correct analysis of cylinder contents in the field and at the
blending station
If there is any doubt about the O2 rating of the cylinder it should:
Be handled as oxygen rated
Never be filled again
