Travel / Shift / Vent
For dives in which the first stop is at 40 fsw or deeper, the travel/shift/vent time includes the 20 second ascent from 40 to 30 fsw as well as the time required to shift the console to oxygen, vent the divers, and confirm that the divers are on oxygen.
02 Air breaks for in water air Decompression required every ___ for ___
SURD02 begins at ___FSW and ends @ ___ in the chamber @ a maximum travel rate of ___FSW in water and ___FSW in the chamber
40 FSW, 50FSW chamber, 40FPM, 100FPM
SURD02 Time from 40FSW to 50 in the chamber should take ___minutes to avoid a penalty
SURD02 periods are spent at which depths
50 - :15 half period
40 - 2-4
30 - any remaining periods
The first period consists of 15 minutes on oxygen at 50
fsw followed by 15 minutes on oxygen at 40 fsw. Periods 2–4 are spent at 40
fsw. If more than 4 periods are required, the remaining periods are spent at 30
Ascent in the chamber is @ __FPM, Interrupt 02 periods every __mins for __mins, air time is considered ___time. Divers surface on ____air.
30FPM, :30, :05, dead, chamber
Surface decompression after divers switched to 02 formula
Multiply remaining 02ntime @ stops by 1.1, divide by 30, round up to the next half period.
SURD02 while divers were decompressing on air
Air/02 = ratio, Missed Air time/ratio, round up X1.1/30
Exceptional exposure dives
Deeper than 190
in-water deco greater than :90
Surd02 greater than 4 periods
Early arrival to first deco stop
Begin stop when required travel time is completed
If first stop is an 02, shift to 02, begin time when divers are confirmed of 02 and required travel time is completed.
Delay greater than a minute shallower than 50 @ first deco stop
round up to the next minute add delay to the first deco stop time
Delay greater than a minute deeper than 50 arriving at first deco stop
Recompute T/S, if a deeper stop is now required add to curent stop do not go deeper.
Delay in ascent between airstops
Disregard if less than 30 seconds
Delay leaving an oxygen stop at 30 fsw or delay between oxygen stops at
30 and 20 fsw.
Subtract any delay in leaving the 30 fsw oxygen stop or any
delay during travel from 30 to 20 fsw on oxygen from the subsequent 20-fsw
oxygen stop time. If the delay causes the total time on oxygen deeper than 20
fsw to exceed 30 minutes, shift the diver to air at the 30-minute mark. When
the problem has been resolved, shift the diver back to oxygen and resume
decompression. Ignore any time spent on air.
SURD02 Delay in travel Greater than :05 penalties
For surface intervals greater than 5 minutes but less than or equal to 7 minutes, increase the oxygen time at 50 fsw
from 15 to 30 minutes.
2 periods or fewer TT5
2 periods or more TT6
A SurDO2 schedule calls for two 30-min oxygen periods in the chamber.
The chamber oxygen supply is lost permanently after 28 minutes on oxygen at 50
and 40 fsw. Chamber air is the only gas available. The remaining oxygen time is (2
× 30) – 28 = 32 minutes. The original decompression schedule calls for 52 and 140
minute in-water air decompression stops at 30 and 20 fsw for a total air stop time
of 192 minutes. The corresponding oxygen stop times are 13 and 34 minutes, for a
total of oxygen stop time of 47 min. The ratio of air stop time to oxygen stop time
is 192/47 = 4.08. The remaining chamber air time is 32 × 4.08 = 131 minutes. This
time is allocated as follows: 13 min at 40 fsw (131 × 0.1), 26 min at 30 fsw (131 ×
0.2), and 92 min at 20 fsw (131 × 0.7).