Oxygen exposure – SUUNTO D9 User Manual

Page 108

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ALTITUDE DIVING

The atmospheric pressure is lower at high altitudes than at sea level. After traveling to
a higher altitude, the diver will have additional nitrogen in his body, compared to the
equilibrium situation at the original altitude. This “additional” nitrogen is released gra-
dually in time and equilibrium is reached. It is recommended that you acclimate to the
new altitude by waiting at least three hours before making a dive.

Before high altitude diving, the instrument must be set to the Altitude Adjustment mo-
de to adjust the calculations for the new altitude. The maximum partial pressures of
nitrogen allowed by the mathematical model of the dive computer are reduced accor-
ding to the lower ambient pressure.

As a result, the allowed no-decompression stop limits are considerably reduced.

SURFACE INTERVALS

The dive computer requires a minimum surface interval of 5 minutes between dives.
If a surface interval is shorter than 5 minutes, the next dive is treated as a continuati-
on of the previous dive.

10.3. OXYGEN EXPOSURE

The oxygen exposure calculations are based on currently accepted exposure time li-
mit 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 upped to the next higher per-
centage value

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