Nitrox maximum depths

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 1.4Maximum depth for partial pressure of oxygen (PPO2) of 1.6
21%5766
22%5463
23%5160
24%4857
25%4654
26%4452
27%4249
28%4047
29%3845
30%3743
31%3542
32%3440
33%3238
34%3137
35%3036
36%2934
37%2833
38%2732
39%2631
40%2530

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