Diver Safety; Compressed Air - Suunto DW141 Safety And Regulatory Information Manual

3.2.1 Diver safety

Because any decompression model is purely theoretical and does not monitor
the actual body of a diver, no decompression model can guarantee the absence
of DCS. Experimentally it has been shown that the body adapts to decompression
to some degree when diving is constant and frequent. Two personal adjustment
settings (P-1 and P-2) are available for divers who dive constantly and are ready to
accept greater personal risks.
CAUTION: Always use the same personal and altitude adjustment settings for
the actual dive and for the planning. Increasing the personal adjustment setting
from the planned setting as well as increasing the altitude adjustment setting
can lead to longer decompression times deeper and thus to larger required gas
volume. You can run out of breathing gas underwater if the personal adjustment
setting has been changed after dive planning.
3.3 Selecting altitude setting
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.
The atmospheric pressure is lower at high altitudes than at sea level. After traveling
to a higher altitude, you will have additional nitrogen in your body, compared to the
equilibrium 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.
WARNING: Traveling to a higher elevation can temporarily cause a change in
the equilibrium of dissolved nitrogen in the body. It is recommended that you
acclimatize to the new altitude before diving.
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.
4 GASES

4.1 Compressed air

This device is recommended for use with compressed air. The compressed air
supply must comply with the quality of compressed air specified in the EU standard
EN 12021:2014 (requirements for compressed gases for breathing apparatus).
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