O2% | Oxygen percentage or oxygen fraction in |
| the breathing gas. Standard air has 21% |
| oxygen. |
Oxygen partial pressure | Limits the maximum depth to which the |
| used Nitrox mixture can safely be used. The |
| maximum partial pressure limit for enriched |
| air diving is 1.4 bar. The contingency partial |
| pressure limit is 1.6 bar. Dives beyond this |
| limit have the risk for immediate oxygen |
| toxicity. |
PO2 | Abbreviation for oxygen partial pressure. |
RGBM | Abbreviation for Reduced Gradient Bubble |
| Model. |
Reduced Gradient Bubble Model
Modern algorithm for tracking both dissolved and free gas in divers.
Repetitive dive | Any dive whose decompression time limits |
| are affected by residual nitrogen absorbed |
| during previous dives. |
Residual nitrogen | The amount of excess nitrogen remaining in |
| a diver after one or more dives. |
SURF TIME | Abbreviation for surface interval time. |
Surface interval time | Elapsed time between surfacing from a dive |
| and beginning a descent for the subsequent |
| repetitive dive. |
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