The ascent time (ASC TIME) is the minimum
amount of minutes needed to reach the surface in a
decompression dive. It includes: The time needed to
ascend to the ceiling at an ascent rate of 10 m/min
[33 ft/min]
plus
The time needed at the ceiling (The ceiling is the
shallowest depth to which you should ascend).
plus
The time needed to reach the surface after the ceil-
ing has been removed.
The ascent time will increase if you:
• remain at depth
• ascend slower than 10 m/min [33 ft/min], or
• make your decompression stop deeper than at the
ceiling.
These factors will also increase the amount of air
required to reach the surface.
21
Figure 3.13
Decompression Dive,
Below the Ceiling Zone
The minimum ascent
time is 4 minutes. The
upward pointing arrow
tells you to ascend. the
ceiling is at 3m (10 ft).
MAX
DIVE TIME
CEILING
ASC
A 1
A
m
S
C
S
P
E
E
D
HIS
LOG
ALT
SET
PLAN
Figure 3.14
Decompression Dive,
at the Ceiling Zone
The two arrows [a] point
at each other (“hour
glass”). You are at the
ceiling zone at 3.5m
(11ft) [c] and your mini-
mum ascent time is 3
minutes [d]. The ceiling
is at 3m (10ft) [b].
MAX
DIVE TIME
CEILING
ASC
A 1
A
m
S
C
S
P
E
E
D
HIS
LOG
ALT
SET
PLAN
b
a
d
c
WARNING
YOUR ACTUAL ASCENT TIME
MAY BE LONGER THAN
DISPLAYED ON THE
IQ-400.
!
!
WARNING
NEVER ASCEND ABOVE THE CEILING!
You must not ascend above the ceiling. In order
to avoid doing so by accident, you should stay
slightly below the ceiling. The ceiling zone is the
shallowest depth range to which you should
ascend when in decompression.
!
!