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Diving with microbubble levels
V Diving with microbubble levels (MB)
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The following chapter deals with the characteristics of diving with microbubble levels (MB levels).
For general information about displays and features of diving with XP AIR see chapter III.
Microbubbles
are tiny bubbles that can build up inside a diver's body during any dive and normally dissipate
naturally during an ascent and on the surface after a dive. Dives within no-stop time and observance of
decompression stops do not prevent the formation of microbubbles in the venous blood circulation.
Dangerous microbubbles are those migrating into the arterial circulation. The reasons for the migration from the
venous blood circulation to the arterial circulation can be a great many microbubbles collecting in the lungs.
SUBGEAR has equipped XP Air computers with a technology to protect from microbubbles.
The diver chooses – according to his/her needs – an MB level and influences through it the level of
protection from microbubbles. Diving with MB levels requires additional ascent stops (level stops), the
ascent is slowed down and the body gets more time to desaturate. This works contrary to the formation
of the microbubbles and increases the safety.
XP AIR features
6 microbubble levels
(L0-L5). Level L0 corresponds to the decompression model ZH-L8
ADT and does not require level stops due to microbubble formation. Levels L1 to L5 offer additional
protection from microbubble formation with level L5 offering the highest protection.
Similar to the display of information during decompression dives or dives within no-stop time, XP AIR
displays depth and duration of the first level stop as well as the total time of ascent as soon as the MB
no-stop time has run out. As the MB no-stop time is shorter than the ordinary no-stop time a diver will
be required to carry out a stop (level stop) sooner than a diver using level L0.
If a diver ignores a required level stop, XP AIR will change over to a lower MB level and the dive can
not be completed with the initially chosen MB level. E.g. If a diver sets level L4 on XP AIR prior to the
dive and during the dive ignores the stops recommended XP AIR will automatically adjust the setting
to level L3 or lower.
1 Comparison of dives with MB level L0 and MB level L5
When two XP AIRs are used simultaneously, one unit is set for example to MB level L5, the other to L0,
the no-stop time will be shortened and level stops will be required before the diver has the obligation of
a decompression stop. These additional level stops help dissipate the microbubbles.
3m/10ft
6m/20ft
9m/30ft
12m/40ft
15m/50ft
Time
Depth
Microbubble
level
Microbubble accumulation
at the end of dive
Stop depth
L0
L5
L0
L5
m
DECO STOP
m
LEVELSTOP
m
LEVELSTOP
NO STOP
m
LEVELSTOP
NO STOP
NO STOP
NO STOP
DECO
ft
ft
ft
ft
Decompression values
Level stop values
Decompression obligation, ->32