situation at the original altitude. This 'additional' nitrogen is released gradually over time and
equilibrium is restored. It is recommended that you acclimatize to a new altitude by waiting at
least three hours before making a dive.
Before high-altitude diving, you need to adjust the altitude settings of your dive computer so
that the calculations take into account the high altitude. The maximum partial pressures of
nitrogen allowed by the mathematical model of the dive computer are reduced according to
the lower ambient pressure.
This setting automatically adjusts the decompression calculation according to the given
altitude range. You can
find the setting under Dive settings » Parameters » Altitude and
select from three ranges:
•
0 – 300 m (0 – 980 ft) (default)
•
300 – 1500 m (980 – 4900 ft)
•
1500 – 3000 m (4900 – 9800 ft)
As a result, the allowed no decompression stop limits are considerably reduced.
WARNING: SET THE CORRECT ALTITUDE SETTING! When diving at altitudes greater
than 300 m (1000 ft), the altitude setting must be correctly selected in order for the computer
to calculate the decompression status. The dive computer is not intended for use at altitudes
greater than 3000 m (10000 ft). Failure to select the correct altitude setting or diving above
the maximum altitude limit will result in erroneous dive and planning data.
3.9.3. 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. For example:
•
The displayed oxygen exposure calculations are raised to the next higher percentage
value.
•
The CNS% limits up to 1.6 bar (23.2 psi) are based on 1991 NOAA Diving Manual limits.
•
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 that all
warnings and displays occur at the appropriate phases of a dive. For example, the following
information is provided before and during a dive when the computer is set in Air/Nitrox:
•
The selected O
2
% (and possible helium %)
•
CNS% and OTU
•
Audible
notification when CNS% reaches 80%, then notification when 100% limit is
exceeded
•
Notifications when OTU reaches 250 and then again when 300 limit is exceeded
•
Audible alarm when pO
2
value exceeds the preset limit (pO
2
high alarm)
WARNING: WHEN THE OXYGEN LIMIT FRACTION INDICATES THAT THE MAXIMUM
LIMIT IS REACHED, YOU MUST IMMEDIATELY TAKE ACTION TO REDUCE OXYGEN
EXPOSURE. Failure to take action to reduce oxygen exposure after a CNS%/OTU warning is
given can rapidly increase the risk of oxygen toxicity, injury, or death.
Suunto D5
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