The maximum operational depths (MOD) in metres for various Nitrox mixes and oxygen allowances are shown in the table below. Divers are responsible for diving with gases which they have been trained to use.
| Fraction of oxygen (FO2) | Maximum depth for partial pressure of oxygen (PPO2) of 1.4 | Maximum depth for partial pressure of oxygen (PPO2) of 1.6 |
|---|---|---|
| 21% | 57 | 66 |
| 22% | 54 | 63 |
| 23% | 51 | 60 |
| 24% | 48 | 57 |
| 25% | 46 | 54 |
| 26% | 44 | 52 |
| 27% | 42 | 49 |
| 28% | 40 | 47 |
| 29% | 38 | 45 |
| 30% | 37 | 43 |
| 31% | 35 | 42 |
| 32% | 34 | 40 |
| 33% | 32 | 38 |
| 34% | 31 | 37 |
| 35% | 30 | 36 |
| 36% | 29 | 34 |
| 37% | 28 | 33 |
| 38% | 27 | 32 |
| 39% | 26 | 31 |
| 40% | 25 | 30 |
A rough formula is given by:
Depth = ( ( Oxygen Allowance * 10) / Oxygen ratio ) – 10
eg. for Allowance of 1.4 and a Oxygen conc of 32%
Depth = ( (1.4 * 10) / 0.32) – 10
Depth = (14 / 0.32) – 10
Depth = 43.75 – 10
Depth = 33.75m
