Stage Depth (fsw): 244'

Decompression Procedure: In/~Wat&r

Max Depth (fsw): £4-9'

Divers' Condition: ^^

Diving Remarks:

Figure 14-1. HeÜ2 Diving Chart.

Figure 14-1. HeÜ2 Diving Chart.

Figure 14-2. In-Water Decompression Dive Profile for a 249 fsw/:18 Dive. CHAPTER 14 — Surface-Supplied Mixed-Gas Diving Procedures

D procedures are preferred over in-water decompression procedures in routine operations. Normal SUR D procedures improve the diver's comfort and safety but increase total decompression time and oxygen consumption. Emergency SUR Ds are used for handling CNS oxygen toxicity symptoms, systems failures and other emergency conditions. Emergency surface decompression allows the diver to be removed from the water in the shortest possible time.

14-3.7 Normal SUR D Procedures Using Oxygen. A diver is eligible for normal surface decompression if he has been on oxygen at 40 fsw for a length of time equal to that of the 50-fsw stop. If there is no 50-fsw stop, 10 minutes on oxygen at 40 fsw is required.

Example. If the 50-fsw stop time is 12 minutes, the diver must remain on oxygen at 40 fsw for 12 minutes before normal surface decompression can be implemented.

14-3.7.1 Initiating Normal Surface Decompression. To initiate normal surface decompression:

1. Bring the diver to the surface at 40 fsw/min and undress him.

2. Place the diver in the recompression chamber.

3. Compress on air to 40 fsw at a maximum compression rate of 80 fsw/min and place the diver on 100 percent oxygen by mask. The interval from leaving 40 fsw in the water to arriving at 40 fsw in the chamber cannot exceed 5 minutes.

4. At 40 fsw in the chamber, the diver breathes oxygen for 30-minute periods separated by 5-minute air breaks. The number of oxygen periods required depends on the time of the 40-fsw water stop as indicated in Table 14-3.

Table 14-3. Recompression Chamber Breathing Requirements.

Water Stop

Oxygen Breathing Period(s)

30 minutes or less

1 period

31-60 minutes

2 periods

61-90 minutes

3 periods

Greater than 90 minutes

4 periods

5. When the last oxygen breathing period has been completed, return the diver to breathing chamber air.

6. Ascend to the surface from 40 fsw in the chamber at a rate of 30 feet per minute.

A normal surface decompression dive chart is shown in Figure 14-3. A normal surface decompression dive profile is shown in Figure 14-4.


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