Advanced Recreational Trimix

Trimix allows divers to significantly reduce the effects of nitrogen narcosis ("being narked") and therefore be able to focus and perform at greater depths.

The Advanced Recreational Trimix course allows the diver to plan and execute dives to 160 fsw by reducing the nitrogen and replacing it with helium.

Helium is an inert or "noble gas" that, when breathed by the diver, has no significant effect on the human body. The diver is now able to choose a most appropriate "life sustaining" oxygen mixture for the dive by reducing the Equivalent Narcotic Depth (END). END represents the equivalent depth / effects that a diver would feel if they were using regular air - EANx 21%

In the Enriched Air course we learn that the phrase "36%" represents a breathing gas of 36% oxygen and therefore 64% Nitrogen. In the Advanced Recreational Trimix Course we breath mixtures such as 32/15. In this example we have 32% Oxygen and 15% Helium, by default we have 53% Nitrogen. As such the nitrogen percentage is never quoted.

The table below demonstrates the different END's of gas mixes at different physical depths. For example at 150 fsw Trimix 28/25 only has a narcotic depth of 76 fsw.



The Advanced Recreational Trimix course limits the END to 80 fsw. Cells shaded in grey are therefore for example purposes only