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Dive time Elapsed time between leaving the surface to descend, and
returning to the surface at the end of a dive.
EAD Abbreviation for equivalent air depth.
EAN Abbreviation for enriched air nitrox.
Enriched Air Nitrox Also called Nitrox or Enriched Air = EANx. Air that has
some oxygen added. Standard mixes are EAN32 (NOAA
Nitrox I = NN I) and EAN36 (NOAA Nitrox II = NN II).
Equivalent Air Depth Nitrogen partial pressure equivalent table.
Floor The deepest depth during a decompression stop dive at
which decompression takes place.
Freediver A breath-holding diver whose only source of oxygen are
his lungs fi lled with surface air.
Half-time After a change in ambient pressure, the amount of time
required for the partial pressure of nitrogen in a theoretical
compartment to go half-way from its previous value to
saturation at the new ambient pressure.
Hypercapnia Increased amount of carbon dioxide in the blood. A
diver who does not rest adequately between breath-hold
dives will have elevated carbon dioxide levels. This can
predispose hin to carbon dioxide toxicity or blackout.