Suunto Favor Air User Manual page 35

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Unlike the U.S. Navy tables, the FAVOR AIR interpolates between depths, giving a diver
"credit" for time spent in shallower water, rather than calculating no-decompression
limits based on the maximum depth of a dive. As a result, multi-level no-decompression
dive times permitted by the FAVOR AIR are often longer than those that would be
allowed by the U.S. Navy tables.
WARNING!
THE USER SHOULD BE AWARE THAT ANY DIVE, INCLUDING ONES WITHIN THE
U.S. NAVY TABLES OR THE FAVOR AIR LIMITS, DOES CARRY SOME RISK OF
DECOMPRESSION SICKNESS!
Compartments and Half Times
When you dive with the FAVOR AIR, it measures and displays depths and times as your
dive progresses. It shows you available no-decompression time and possible
decompression required based upon the following five factors:
1. your present depth,
2. excess nitrogen absorbed during earlier portions of the dive,
3. residual nitrogen remaining from previous dives,
4. the no-decompression limits that apply to that depth,
5. the personal/altitude adjustment mode in use.
Back on the surface, the FAVOR AIR will continue to calculate the no-decompression
dive times available for various depths on the next dive. As the surface interval
increases, so does the available dive time for the next dive.
To perform these calculations, the FAVOR AIR continuously models the absorption and
release of excess nitrogen from theoretical compartments. Each compartment absorbs
and releases nitrogen at a different rate. The compartments that absorb and release
nitrogen rapidly are believed to have a high tolerance for excess nitrogen, whereas
compartments that absorb and release nitrogen more slowly are believed to be more
sensitive.
The no-decompression limits in the U.S. Navy tables are based upon six theoretical
compartments for single dives, and one compartment for surface intervals and repetitive
dives. If you are familiar with table theory, you may know that they are
characterized by half times (i.e. the time required for 50 % equilibration to a pressure
change) ranging from 5 minutes to 120 minutes.
The FAVOR AIR includes the same six compartments, and two additional
compartments for an increased range of the mathematical model. The calculations are
based on all eight compartments for all phases of diving, including surface intervals and
repetitive dives. The FAVOR AIR's half times range from 2.5 to 320 minutes. The multi-
level tissue calculations are based on the modified Haldanean principle incorporating
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