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8. GLOSSARY
Altitude dive A dive made at an elevation greater than 300 m
[1000 ft] above sea level.
Ascent rate The speed at which the diver ascends toward the
surface.
ASC RATE Abbreviation for ascent rate.
Ascent time The minimum amount of time needed to reach the
surface on a decompression dive.
ASC TIME Abbreviation for ascent time.
Ceiling On a decompression dive the shallowest depth
to which a diver may ascend based on computer
nitrogen load.
Ceiling Zone On a decompression dive the zone between the
ceiling and the ceiling plus 1.8 m [6 ft]. This depth range
is displayed with the two arrows pointing toward each
other (the “hour glass” icon).
CNS Abbreviation for central nervous system toxicity.
Central Nervous System Toxicity
Toxicity caused by oxygen. Can cause a variety of
neurological symptoms. The most important of which
is an epileptic-like convulsion can cause a diver to
drown.
CNS% Central Nervous System toxicity limit fraction. Also
note Oxygen Limit Fraction and whole-body toxicity.
Compartment See “Tissue group”.
DAN Divers Alert Network.
DCS Abbreviation for decompression sickness.
Decompression Time spent at a decompression stop or range before
surfacing, to allow absorbed nitrogen to escape
naturally from tissues.
Decompression range On a decompression dive the depth range, between
the fl oor and ceiling, within which a diver must stop
for some time during ascent.
