The same questions must be asked for the second dive of the day: What is the allowable dive time for this dive? Which factor will be the limiting one?
- Surface interval time: 2.5 hr. (150 min.)
- Calculated SAC rate: 18 L p/m or 0.65 cu. ft. p/m
- Gas supply: 11.1 L/80 cu. ft. (Cylinder was re-filled to 200 bar/3000 psi.)
- Planned depth: 15 m/49 ft.
- Planned dive time: 30 min.
The changing pressure group designation represents the excess nitrogen in your body between dives. To determine your group designation, you need to track the time on the surface. Refer to Table 2, and find F. Then, look along the row to find the time where 2.5 hours would fall—between 2:29 and 3:57 hours. Then go down the column to the new pressure group. The new pressure group designation is C.