CHAPTER 14 — Surface Supplied Mixed Gas Diving Procedures
Change A 14-5
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Shift the diver from the bottom mixture back to air.
!
Ventilate the diver.
!
Confirm the diver is on air.
!
Have the diver begin ascent to the surface.
!
If desired, another dive may be performed following a dive aborted 100 fsw
and shallower. Add the bottom time of the aborted dive to the bottom time of
the new dive when calculating a table and schedule for the new dive.
2.
If it is necessary to abort a dive deeper than 100 fsw:
!
Follow the normal decompression schedule to the surface.
!
Repetitive diving is not allowed following a dive aborted deeper than 100 fsw.
14-3.7
Procedures for Shifting to 50 Percent Helium/50 Percent Oxygen at 90 fsw. All
dives except no-decompression dives require a shift from bottom mixture to 50%
helium 50% oxygen at 90 fsw during decompression. Follow these steps:
1.
Shift the console to 50% helium 50% oxygen when the diver reaches 90 fsw.
2.
If there is a decompression stop at 90 fsw, ventilate each diver for 20 seconds
at 90 fsw.
3.
Confirm the divers are on 50% helium 50% oxygen
4.
If there is no decompression stop at 90 fsw, delay ventilation until arrival at the
next shallower stop.
Gas shift time is included in the stop time.
14-3.8
Procedures for Shifting to 100 Percent Oxygen at 30 fsw. All in-water decomp-
pression dives require a shift to 100 percent oxygen at the 30 fsw stop. Upon
arrival at the stop, ventilate each diver with oxygen following these steps:
1.
Shift the console to 100% oxygen when the diver reaches 30 fsw.
2.
Ventilate each diver for 20 seconds.
3.
Verify the diver's voice change.
Gas shift time is included in the stop time.
14-3.9
30 fsw and 20 fsw Water Stops. At the 30 fsw and 20 fsw water stops, the diver
breathes oxygen for 30 minute periods separated by 5 minute air breaks. The air
breaks do not count toward required decompression time. When an air break is
