SSI ENRICHED AIR NITROX EXAM
QUESTIONS WITH CORRECT
ANSWERS
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 - Correct Answers -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 - Correct
Answers -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 - Correct Answers -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% - Correct Answers -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 - Correct Answers -A ppO2 of 1.6 ata
A common misconception is that, when compared to air, nitrox enables divers to dive:
longer
shallower
shorter
deeper - Correct Answers -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 - Correct Answers -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 - Correct Answers -EAN32/EAN36
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
The required exposure time before symptoms arise is well beyond the duration of most
sport dives - Correct Answers -The required exposure time before symptoms arise is
well beyond the duration of most sport dives
Since CNS Oxygen Toxicity is among the greatest of risks in nitrox diving, you must be
able to recognize:
Its positive aspects in deep diving
Its warning signs and symptoms, both in yourself and others
Its warning signs and symptoms, only in yourself
Its treatment - Correct Answers -Its warning signs and symptoms, both in yourself and
others
QUESTIONS WITH CORRECT
ANSWERS
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 - Correct Answers -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 - Correct
Answers -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 - Correct Answers -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% - Correct Answers -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 - Correct Answers -A ppO2 of 1.6 ata
A common misconception is that, when compared to air, nitrox enables divers to dive:
longer
shallower
shorter
deeper - Correct Answers -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 - Correct Answers -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 - Correct Answers -EAN32/EAN36
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
The required exposure time before symptoms arise is well beyond the duration of most
sport dives - Correct Answers -The required exposure time before symptoms arise is
well beyond the duration of most sport dives
Since CNS Oxygen Toxicity is among the greatest of risks in nitrox diving, you must be
able to recognize:
Its positive aspects in deep diving
Its warning signs and symptoms, both in yourself and others
Its warning signs and symptoms, only in yourself
Its treatment - Correct Answers -Its warning signs and symptoms, both in yourself and
others
