Dive Terminology
- Air time remaining (ATR)
-
The time you may remain at the current depth until an ascent at 9 m/min. (30 ft./min.) would result in surfacing with reserve pressure remaining.NOTE: If multiple tanks are included in gas consumption calculations, air time remaining is calculated using the combined pressure and reserve pressure of all tanks.
Decompression stops are included in the calculations, but safety stops are not.
- Pressure-based surface air consumption (PSAC)
-
The change in pressure over time, normalized to 1 ATM.
- Respiratory minute volume (RMV)
-
The change in gas volume at ambient pressure over time.
- Volumetric surface air consumption (SAC)
-
The change in gas volume over time, normalized to 1 ATM.