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 the reserve pressure.

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.