Multi level dive
A single or repetitive dive that includes time spent at various depths and
whose no decompression limits are therefore not determined solely by
the maximum depth attained.
Nitrox
In sports diving, refers to any mix with a higher fraction of oxygen than
standard air.
NOAA
United States National Oceanic and Atmospheric Administration.
No decompression time
The maximum amount of time a diver may remain at a particular depth
without having to make decompression stops during the subsequent as-
cent.
No decompression dive
Any dive which permits a direct, uninterrupted ascent to the surface at
any time.
NO DEC TIME
Abbreviation for no decompression time limit.
OEA = EAN = EANx
Abbreviations for oxygen enriched air nitrox.
OLF
Abbreviation for oxygen limit fraction.
OTU
Abbreviation for oxygen tolerance unit.
Oxygen tolerance unit
Used to measure the whole-body-toxicity.
Oxygen limit fraction
A term used by Suunto for the values displayed in the oxygen toxicity bar
graph. The value is either the CNS% or the OTU%.
O
2
%
Oxygen percentage or oxygen fraction in the breathing gas. Standard air
has 21% oxygen.
Oxygen partial pressure
Limits the maximum depth to which the nitrox mixture can be safely used.
The maximum partial pressure limit for enriched air diving is 1.4 bar. The
contingency partial pressure limit is 1.6 bar. Dives beyond this limit risk
immediate oxygen toxicity.
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