Oxygen exposure – SUUNTO Cobra User Manual
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DIVER ATTENTION SYMBOL - ADVICE TO EXTEND
SURFACE INTERVAL
Some patterns of diving cumulatively add a higher risk of DCI, e.g. dives with
short surface intervals, repetitive dives deeper than earlier ones, multiple ascents,
substantial multiday diving. When this is detected in addition to adapting the
decompression algorithm Suunto RGBM will in some circumstances also advise,
with the Diver Attention Symbol (review page 33) that the diver extend the surface
interval
6.3. OXYGEN EXPOSURE
The oxygen exposure calculations are based on currently accepted exposure time
limit tables and principles. In addition to this the dive computer uses several methods
to conservatively estimate the oxygen exposure. These include for example:
•
the displayed oxygen exposure calculations are rounded to the next
higher whole percentage value
•
for recreational scuba diving, the recommended upper limit of 1.4 bar
PO
2
is used as a default
•
the CNS% limits up to 1.4 bar are based on 1991 NOAA Diving Manual
limits, but the limits higher than 1.4 bar are signifi cantly shortened
•
the OTU monitoring is based on the long-term daily tolerance level and
the recovery rate is reduced.
Oxygen related information displayed by the dive computer is also designed to
ensure all warnings and displays in the appropriate phases of a dive. E.g. the
following information will be shown before and during a dive, when the computer
is set in Nitrox mode:
•
the selected O
2
%
•
the color-coded OLF% bar graph for either CNS% or OTU%
•
audible alarms are given and the OLF bar graph starts to blink when the
80% and 100% limits are exceeded
•
the blinking of the bar graph stops, when the PO
2
is below 0.5 bar
•
audible alarms are given and the actual PO
2
value blinks when it exceeds
the preset limit
•
in dive planning the maximum depth according to the O
2
% and
maximum PO
2
selected.