Operations Manual Perdix
Manual DocRev B
41
A Gradient Factor is simply a decimal
fraction (or percentage) of the M-value
Gradient.
Gradient Factors (GF) are defined from 0%
to 100%.
A Gradient Factor of 0% represents the
ambient pressure line.
A Gradient Factor of 100% represents the
M-value line.
Gradient Factors modify the original
M-value equations for conservatism within
the decompression zone.
The lower Gradient Factor value (GF Lo)
determines the depth of the first stop. Used
to generate deep stops to the depth of the
"deepest possible deco stop"
The higher Gradient Factor value (GF
Hi) determines the surfacing tissue
supersaturation.
Graph from Erik Baker’s “Clearing Up The Confusion About Deep Stops”
Pressue Graph: Gradient Factors
100% 80% 60% 40% 20%
0%
Ambient Pressure, absolute (increasing depth > )
Surf
ac
e Pr
es
sur
e
Linear
function
for gradual
change in
Gradient
Factors
M-value
Gradient
C
ompartment inert gas pr
es
sur
e
, absolut
e
y
0
0
x
Ambient Pr
es
sue Line
M-
value Line
GF Lo
generates
first stop
GF Hi (surfacing value)
maintains safety margin
First
Stop
