Nitrox for the Beginner

By Dennis M. Pulley

During open water diver training your instructor more than likely mentioned nitrox. This may have been during the discussion of dive tables, computer use or continuing education classes available through your local dive retailer. Here are some key questions and answers about nitrox for the new diver. What is nitrox?
The actual mixture we use when we dive nitrox is called Enriched Air Nitrox (EAN). EAN is a blend of oxygen and nitrogen in which the percentage of oxygen is greater than normal air (approximately 21 percent). This means the percentage of nitrogen in the mixture has been reduced and the percentage of oxygen has been increased.

What are some of the benefits of using nitrox?

You might recall from your open water diver training that excess nitrogen can be dangerous. With Enriched Air Nitrox, the reduced nitrogen allows you to dive for longer periods at some depths and accumulate less nitrogen in your system. You can also dive with nitrox and use the regular air tables, or air computer, for an added measure of safety.

What is required for training?
Because there are some important safety considerations when using nitrox, you do need to take a class. Classes typically consist of an academic review, pool session and open water dives.

Most classes cover such topics as:

• What is nitrox?
• Physics and physiology of nitrox
• Equipment for nitrox
• Planning and performing a nitrox dive

There are special tables that you use for planning nitrox dives and an oxygen analyzer. This analyzer will tell you the amount of oxygen in the nitrox blend so you’ll be able to plan a dive correctly. Dive tables for the most common nitrox mixes like NAUI Recreational Ean 32 No - Deco Dive Tables can be found at

Is there special equipment for nitrox diving?
It is best to follow the manufacturer’s recommendations when deciding what gear to use for nitrox diving for gas mixtures up to 40 percent oxygen. Oxygen does not mix well with some of the lubricants that are typically used when servicing scuba equipment, so equipment manufacturers have designed special O-rings and lubricants that can be used with EAN to limit problems. Because of the higher percentage of oxygen in EAN, there are special considerations for the use of cylinders, valves and regulators. Additionally, cylinders that will be used for nitrox often need to be cleaned to be used safely. Also, dive computers like the Oceanic Geo Air/Nitrox Computer Watch found at can track and calculate your dive tables for you.

Is nitrox available where I travel?
Every day more locations around the world are able to supply nitrox to divers. Dive retailers, resorts and live-aboard dive boats are seeing the benefits of diving with nitrox. Before your next local or exotic trip, find out if nitrox will be available and get training before you leave.

For more information about nitrox, contact your local dive retailer or instructor.