• slider Image
  • slider Image
  • slider Image
  • slider Image
  • slider Image
  • slider Image
  • slider Image
  • slider Image
  • slider Image
  • slider Image

Diving with Enriched Air (Nitrox)

Enriched Air or Nitrox diving is steadily gaining popularity among divers who want to maximize their bottom time, minimize their surface intervals and reduce the fatigue often associated with making repetitive dives.  It also reduces the chances of having common complications that divers may suffer like nitrogen narcosis and decompression sickness.

The word "Nitrox" is a combination of the words nitrogen and oxygen, and can actually be used to mean a mix of the two gasses in any ratio. The air on Earth's surface, which is comprised of about 78% nitrogen and 21% oxygen (with 1% trace gasses), is a form of Nitrox.  Nitrox or Enriched Air used for diving, however, has had more Oxygen added to it and different rules and calculations apply.  This is why only divers who have learned how to manage this additional oxygen in the mix and completed a Nitrox certification course can dive with Enriched Air (Nitrox).

There are two general types of Nitrox blends used for diving: Nitrox I, also called Nitrox 32, which is comprised of 32% oxygen and 68% nitrogen; and Nitrox II, also called Nitrox 36, which is comprised of 36% oxygen and 64% nitrogen.  Enriched Air or Nitrox also has a shorter name, EANx, where x is the percentage of oxygen, ie. EAN32 (32% oxygen in the mix), usually people mean EANx when they say "Nitrox".

The underlying principle behind Nitrox diving is relatively simple. The longer and deeper a diver is underwater, the more nitrogen enters your system. Too much nitrogen in your system can lead to a slew of debilitating illnesses, some of which may ultimately result in death. To combat this, a diver must ascend slowly, make decompression stops, and adhere to the recommended surface interval before the next dive.

For the recreational or sport Nitrox diver, however, the plan is a little different. Since your "Enriched" air has more oxygen and less nitrogen, your body will absorb less nitrogen than the diver that uses a regular scuba tank. As a result, the Nitrox diver may spend more time underwater, less time on decompression stops and surface intervals, and in some cases, may not need to make them at all.

 

  nitrox_tank.jpg

EXAMPLES OF DIVING WITH NITROX

If you do two dives to 20 meters (66 feet) with air and a one hour surface time, the no decompression limited bottom times will be 45 minutes and 24 min, respectively.  Now, if you do the same with EAN40, the bottom times rise to 98 min and 61 min, respectively. (PADI diving tables).

If you do two 25 min dives to 25 meters (83 feet) with air, the surface time will be at least 2 h 19 min (in no decompression limits). With EAN40 you don't even have to have the surface time! (PADI diving tables)

 

 

Many divers also report a benefit of being less tired after diving with Nitrox than after a regular dive, particularly when making repetitive dives in a day or over the course of several days while on a dive trip or live-aboard boat.

While Nitrox certainly has its benefits, there are some additional precautions Nitrox divers should observe, which is why training and certification in diving with Nitrox is so important.  Since Nitrox has more oxygen in it, and oxygen is actually toxic at certain depths (read why this is), Nitrox divers have an increased risk of oxygen toxicity.

As a result, Nitrox divers should be sure to test the mix in their tank and observe the depth limitations associated with particular Nitrox mixes.  You will learn about this and more in the PADI Nitrox specialty certification course.

images

More About Nitrox
What pressure (depth) does to Oxygen & More

nitrox_what.gif

PADI eLearning
Start your Nitrox or other PADI course online today

B_nitrox_elearning_02-P.jpg

Useful Nitrox Diving Resources
Dive Tables, Logs & Helpful Links

B_nitrox_dive-table.jpg