SDI COMPUTER NITROX QUESTIONS
AND ANSWERS
m True - True or False. Oxygen Enriched Air is a term some divers use to refer to Nitrox.
Nitrogen and Oxygen - The air we normally breathe consists primarily of:
Enriched Air, Enriched Air Nitrox, Nitrox, Etc. - A mixture of nitrogen and oxygen in which the percentage
of oxygen is greater than that found in air is generally called:
Blender - The person who creates the Nitrox used to fill scuba cylinders is referred to as a:
EAN21 - Which of the following is not a Nitrox mixture? EAN24, EAN21, EAN40
Longer bottom times and shorter surface intervals - The primary benefits of using Nitrox include:
150 Minutes or 2.5 hours - During any 24-hour period, you can be exposed to a Nitrox mixture at its
Maximum Operating Depth (MOD) for up to:
False - True or False. Dive computers work by monitoring the presences of so-called 'silent bubbles using
ultrasound.
You may not be able to make a direct ascent to the surface without substantially increasing your risk of
decompression sickness and your dive computer may require you to make a series of decompression
stops - What may happen if you go too deep or stay too long?
Pausing at a fixed depth for a specified period of time to allow excess nitrogen to exit you body more
slowly - A decompression stop is:
Specialized training, Additional equipment, and Topside support - To properly engage in decompression
diving requires:
Nitrogen, ascend - Decompression sickness usually occurs when you have an excess amount of
__________ in your body and you ________ too quickly.
Pain in the joints, Numbness and paralysis, and Loss of balance - The most common symptoms of
decompression sickness can include, but are not limited to:
Administration of pure oxygen - The most important first-aid procedure for a diver suspected of suffering
from decompression sickness is:
Recompression in a hyperbaric chamber - Once a diver suspected of suffering from decompression
sickness has been transported to a medical facility, proper treatment will primarily involve:
16 percent - What is the minimum concentration of oxygen required to maintain consciousness at sea
level?
40 percent - The maximum percentage of oxygen that sport divers use in a Nitrox mixture is:
, 6 m/20 ft - What is the maximum recommended depth for using 100 percent oxygen?
In which the Fraction of Oxygen (FO2) is 32 percent - The term EAN32 refers to a Nitrox mixture:
40 m/132 ft - The MOD for EAN32 is:
True - True or False. The term MOD stands for Maximum Operating Depth.
It is safe to use down to the maximum recommended sport diving depth limit of 40m/132 ft and it
provides a good combination of safety and extended bottom time - EAN32 is a good choice for Nitrox
diving because:
1.6 - The maximum partial pressure of oxygen (PO2) we use in Nitrox diving is:
Pulmonary and Central Nervous System (CNS) - Types of oxygen toxicity include:
Oxygen toxicity - The primary risk associated with Nitrox diving (as opposed to diving air) is:
True - True or False. The D in the acronym CONVENTID stands for dizziness.
Scar tissue in the sinuses - Which of the following is not a factor that may increase a diver's susceptibility
to oxygen toxicity?
False - True or False. Divers can limit the adverse effects of long-term exposure to nitrogen by diving
Nitrox less than 20 times a year.
False - True or False. The most important step divers can take to help avoid oxygen toxicity is to never
exceed a PO2 of 2.0.
False - True or False. The two gases that a Nitrox diving computer takes into consideration when
computing your allowable bottom time are nitrous oxide and carbon monoxide.
True - True or False. The minimum surface interval or Nitrox diving is 30 minutes; however, 60 minutes is
preferred.
120 minutes - What is the recommended surface interval after extended dives with Nitrox?
That a cylinder may contain Nitrox and must be accurately analyzed and labeled prior to use. - What
does the presence of a Nitrox tank wrap signify?
True - True or False. The two most important pieces of information that will appear on a Nitrox fill tag or
label are FO2 and MOD.
No changes are needed, unless required by manufacturer's specifications or local laws/regulations. -
What are the changes that must be made to a regulator to prepare it for use with Nitrox mixtures whose
FO2 does not exceed 40 percent?
FO2 - What is the most important setting that must be made to your Nitrox computer before every dive?
To compensate for heat loss on longer dives. - Why may you need additional thermal protection for
Nitrox diving?
AND ANSWERS
m True - True or False. Oxygen Enriched Air is a term some divers use to refer to Nitrox.
Nitrogen and Oxygen - The air we normally breathe consists primarily of:
Enriched Air, Enriched Air Nitrox, Nitrox, Etc. - A mixture of nitrogen and oxygen in which the percentage
of oxygen is greater than that found in air is generally called:
Blender - The person who creates the Nitrox used to fill scuba cylinders is referred to as a:
EAN21 - Which of the following is not a Nitrox mixture? EAN24, EAN21, EAN40
Longer bottom times and shorter surface intervals - The primary benefits of using Nitrox include:
150 Minutes or 2.5 hours - During any 24-hour period, you can be exposed to a Nitrox mixture at its
Maximum Operating Depth (MOD) for up to:
False - True or False. Dive computers work by monitoring the presences of so-called 'silent bubbles using
ultrasound.
You may not be able to make a direct ascent to the surface without substantially increasing your risk of
decompression sickness and your dive computer may require you to make a series of decompression
stops - What may happen if you go too deep or stay too long?
Pausing at a fixed depth for a specified period of time to allow excess nitrogen to exit you body more
slowly - A decompression stop is:
Specialized training, Additional equipment, and Topside support - To properly engage in decompression
diving requires:
Nitrogen, ascend - Decompression sickness usually occurs when you have an excess amount of
__________ in your body and you ________ too quickly.
Pain in the joints, Numbness and paralysis, and Loss of balance - The most common symptoms of
decompression sickness can include, but are not limited to:
Administration of pure oxygen - The most important first-aid procedure for a diver suspected of suffering
from decompression sickness is:
Recompression in a hyperbaric chamber - Once a diver suspected of suffering from decompression
sickness has been transported to a medical facility, proper treatment will primarily involve:
16 percent - What is the minimum concentration of oxygen required to maintain consciousness at sea
level?
40 percent - The maximum percentage of oxygen that sport divers use in a Nitrox mixture is:
, 6 m/20 ft - What is the maximum recommended depth for using 100 percent oxygen?
In which the Fraction of Oxygen (FO2) is 32 percent - The term EAN32 refers to a Nitrox mixture:
40 m/132 ft - The MOD for EAN32 is:
True - True or False. The term MOD stands for Maximum Operating Depth.
It is safe to use down to the maximum recommended sport diving depth limit of 40m/132 ft and it
provides a good combination of safety and extended bottom time - EAN32 is a good choice for Nitrox
diving because:
1.6 - The maximum partial pressure of oxygen (PO2) we use in Nitrox diving is:
Pulmonary and Central Nervous System (CNS) - Types of oxygen toxicity include:
Oxygen toxicity - The primary risk associated with Nitrox diving (as opposed to diving air) is:
True - True or False. The D in the acronym CONVENTID stands for dizziness.
Scar tissue in the sinuses - Which of the following is not a factor that may increase a diver's susceptibility
to oxygen toxicity?
False - True or False. Divers can limit the adverse effects of long-term exposure to nitrogen by diving
Nitrox less than 20 times a year.
False - True or False. The most important step divers can take to help avoid oxygen toxicity is to never
exceed a PO2 of 2.0.
False - True or False. The two gases that a Nitrox diving computer takes into consideration when
computing your allowable bottom time are nitrous oxide and carbon monoxide.
True - True or False. The minimum surface interval or Nitrox diving is 30 minutes; however, 60 minutes is
preferred.
120 minutes - What is the recommended surface interval after extended dives with Nitrox?
That a cylinder may contain Nitrox and must be accurately analyzed and labeled prior to use. - What
does the presence of a Nitrox tank wrap signify?
True - True or False. The two most important pieces of information that will appear on a Nitrox fill tag or
label are FO2 and MOD.
No changes are needed, unless required by manufacturer's specifications or local laws/regulations. -
What are the changes that must be made to a regulator to prepare it for use with Nitrox mixtures whose
FO2 does not exceed 40 percent?
FO2 - What is the most important setting that must be made to your Nitrox computer before every dive?
To compensate for heat loss on longer dives. - Why may you need additional thermal protection for
Nitrox diving?
