Shearwater Petrel
Revision 1.1.0
17
Shearwater Research Inc.
Diluent PPO2
Only displayed in CC mode� Displays in
Flashing Red
when
the partial pressure of the diluent is less than 0�19 or greater
than 1�65�
When performing a manual diluent flush, you can check this
value to see what the expected PPO2 will be at the current
depth�
Fraction Inspired O2 (FiO2)
The fraction of the breathing gas composed of O2� This
value is independent of pressure�
Tissues Bar Graph
The tissues bar graph shows the tissue compartment inert
gas tissue tensions based on the Bühlmann ZHL-16C model�
Note that VPM-B also tracks tensions in the same way�
The fastest tissue compartment is shown on the top, and the
slowest on the bottom� Each bar is the combined sum of the
nitrogen and helium inert gas tensions� Pressure increases
to the right�
The vertical black line shows the inert gas inspired pressure�
The boundary between the green and yellow zones is the
ambient pressure� The boundary between the yellow and red
zone in the ZHL-16C M-Value pressure�
Note that the scale for each tissue compartment above the
green zone is different� The reason the bars are scaled in
this way is so that the tissues tensions can be visualized
in terms of risk (i�e� how close they are as a percentage to
Bühlmann's original super-saturation limits)� Also, this scale
changes with depth, since the M-Value line also changes
with depth�
.99
DilPPO2
FiO2
.42
Ambient pressure
Increasing pressure
M-Value pressure
Inspired inert
gas pressure
16 tissue
compartments
On surface (sat� with air)
After descent
On-gassing
Last deco stop
Some Sample Tissues
Graphs
Summary of Contents for Petrel EXT
Page 1: ...Standalone EXT Models...