Enriched Air — NITROX
Enriched Air – NITROX is any air mixture where the oxygen content is greater than the 21% we normally breath. The two most common mixtures are 32% and 36%, otherwise know as EANx32 and EANx36 respectively.
The principle reason for breathing Enriched Air – NITROX is to extend No Decompression Limit (NDL) bottom times. As divers, we are often required to return to the surface because of Nitrogen absorption. With Enriched Air NITROX we are inhaling less Nitrogen and, therefore, absorbing less Nitrogen and our NDL bottom time increases. For example, on a dive to 50 feet the air NDL is 80 minutes. That same dive with EANx32 increases our NDL to 155 minutes and with EANx36 it increases to 220 minutes. Pretty dramatic difference!
Enriched Air – NITROX can also help in other ways, since Nitrogen absorption is responsible for Decompression Sickness (DCS or “Bends”), if you absorb less Nitrogen, you can reduce the amount that’s in your system and, therefore, reduce the chance of suffering from DCS. You still need to come up slowly from every dive and follow all the other Golden Rules of diving. You can also reduce surface interval times using Enriched Air – NITROX. If you’ve inhaled less Nitrogen then you need less time to off-gas Nitrogen on the surface. Another side benefit to Enriched Air – NITROX is the reduction of that Nitrogen Nap feeling which is common after diving with air.
It all sounds good, but there must be a downside… right?
With Nitrogen TIME is a limiting factor, but with Oxygen DEPTH is the limiting factor. The maximum depth limit for air is 218 feet, with EANx32 it’s 111 feet and EANx36 it’s 95 feet. When you consider that most of the diving we do as recreational divers is in the 30 to 100 foot range anyway, it’s not much of a limiting factor. But the consequences of going too deep is Oxygen Toxicity, which is very serious and can result in seizures and drowning.
However, all you have to do is:
- Receive the proper training.
- Dive responsibly.
- Observe the depth limit for that mixture.
NEVER DIVE ENRICHED AIR – NITROX WITHOUT THE PROPER TRAINING