A blend of oxygen, nitrogen, and helium, trimix is used for deeper dives. Common trimix blends with their calculated maximum depths are:
Gas | max Depth (m) | END (m) | PO2 (bar) |
21/35 | 52 | 30 | 1.3 |
18/45 | 63 | 30 | 1.3 |
15/55 | 79 | 30 | 1.3 |
12/60 | 90 | 30 | 1.2 |
10/70 | 110 | 26 | 1.2 |
These gas blends help mitigate nitrogen narcosis and improve gas efficiency while considering the toxic effects of both oxygen and nitrogen.
Divers select these gases based on the depth of the dive, the duration, and their experience level, allowing for safe exploration of various underwater environments.