Enriched Air Nitrox

Scuba diving with enriched air nitrox gives you more no-decompression time, especially on repetitive scuba dives. If staying down longer and getting back in the water sooner sounds appealing, then don’t hesitate to become an enriched air diver.

Do You Want to Stay Deep, Longer?!

Enriched Air Nitrox Certification

There is often a fair amount of confusion that surrounds the Enriched Air Nitrox (EANx) course. Many people are under the (wrong) assumption that EANx allows a diver to go deeper. In fact the opposite is true as additional oxygen in our breathing gas does create a shallower maximum depth than does traditional air.

In recreational diving terms, enriched air nitrox (EAN) refers to any nitrogen/oxygen gas mixture with an oxygen concentration higher than the 21 percent found in normal air. It is this higher percentage of oxygen, and the proportionately lower percentage of nitrogen, that allows divers to lengthen no-decompression limits, shorten surface intervals and get an added safety buffer for decompression sickness in certain diving circumstances.

Based on the U.S. Navy dive tables, a diver on air at 100 feet reaches their no-decompression limit and must come up after 25 minutes. At 60 feet, the diver’s maximum time would be one hour. Nitrox changes the numbers. When you replace some of the nitrogen with extra oxygen, there’s less nitrogen available, which means it won’t dissolve as quickly, allowing a longer no-decompression limit. This concept is known as the Equivalent Air Depth (EAD). For example, divers at 105 feet with 36 percent nitrox will dissolve nitrogen into their blood and tissues at the same rate as when breathing air at 80 feet. Therefore, the diver’s ordinary no-decompression limit of 20 minutes extends to 40 minutes — that’s double the bottom time!