PADI Enriched Air Diver

Why PADI Enriched Air Diver?

Maximize your time with the upgraded PADI Enriched Air Diver course. Enriched Air Diver saves you time by allowing you to:
-Stay underwater longer
-Get back into the water sooner
-Get your certification while simultaneously completing dives for other PADI courses
Plus, by diving with Enriched Air you may feel less tired on your vacation.

What do I need to start?

All you need is your open water diver certification. (You must be 15 years of age or older).

What will I do?

You will learn preparation and diving procedures involved with enriched air diving.

How soon can I be diving on enriched air?

Just a mini workshop and a couple dives and you’ll be on your way.
-Recommended Course Hours: 12
-Minimum Open Water Training: two dives over one day

What will I need?

You'll need your PADI Enriched Air Crew-Pak, which includes an Enriched Air 32 percent Table, Enriched Air 36 percent Table and Equivalent Air Depth/Oxygen Exposure Table.

What can I do after this

You can apply this Specialty course towards your Master Scuba Diver certification. You also need the PADI Enriched Diver certification if you intend to move into technical diving.

What you will see and do during the course?

You will first have some home study with the Padi Nitrox manual. You we have to sit the Nitrox exam which is just 25 question all of which are covered in the manual. If you should need any help or advise regarding your home study, we are always here to help you. On successful completion of the exam, we will teach you how to analyze a nitrox mix and you will make two dives with Nitrox, at the dive site of your choice.

Some facts about Nitrox Enriched Air

Nitrox refers to any gas mixture composing (excluding trace gases) of nitrogen and oxygen. This includes the normal air that we breathe which is approximately 78% Nitrogen and 21% Oxygen, with around 1% other gases. The most common use of nitrox mixtures containing higher than normal levels of oxygen is in Scuba Diving where the reduced percentage of Nitrogen is advantageous in reducing Nitrogen loadings in the body's tissues. This extends the possible dive time and reducing the risk of decompression sickness. Decompression sickness is known to divers as the bends.

In scuba diving Nitrox is mainly used to reduce the proportion of nitrogen in the breathing gas mixture. Reducing the amount of Nitrogen by increasing the amount of Oxygen reduces the risk of decompression sickness and therefore allowing extended dive times without increasing the need for decompression stops. Nitrox is not a safer gas than compressed air in every respect. Although its use reduces the risk of decompression sickness, it also increases the risk of oxygen toxicity. There is also an added problem with handling it, which is the risk of fire and explosion.

Nitrox is known by many names: Enhanced Air Nitrox, Oxygen Enriched Air, Nitrox, EANx or Safe Air.

Although "nitrox" usually refers to a mixture of nitrogen and oxygen with more than 21% oxygen, it can refer to mixtures that are leaner in oxygen than air. "Enriched Air Nitrox", "Enriched Air" or "EAN" are used to emphasize richer than air mixtures. In "EANx", the "x" indicates the percentage of oxygen in the mix and is dropped when the percentage is known; for example a 32% EANx mix is called EAN32. The two most popular blends are EAN32 and EAN36 (also named Nitrox I and Nitrox II, respectively, or Nitrox32 and Nitrox36). These two most popular mixes have maximum operating depths of about 32 meters and 29 meters respectively when limited to a maximum partial pressure of oxygen of 1. 4 bar. EAN32 is common because it is the mixture with the maximum concentration of oxygen that allows the diver to go to the full depth of recreational diving (30m) "No Decompression Limit" for air.
Nitrox with more than 40% oxygen is uncommon for recreational divers (but more about this later). There are two main reasons for this. The first is that all pieces of diving equipment that come into contact with mixes containing higher proportions of oxygen, particularly at high pressure, need special cleaning and servicing to reduce the risk of fire. The second reason is that richer mixes extend the time the diver can stay underwater without needing decompression stops, but sooner or later there will be a point where the diver’s cylinder will not have enough mix to complete the dive. For example, based on the PADI nitrox recommendations, the maximum operating depth for Nitrox45 would be 21 meters and the maximum dive time available at this depth even with Nitrox36 is nearly 1 hour 15 minutes: a diver with a breathing rate of 20 liters per minute using twin 10 liter, 230 bar cylinders would have completely emptied the cylinders after 1 hour 14 minutes at this depth. And this is with two 10 liter tanks!!

Nitrox is not a deep-diving gas mixture due to the increased proportion of oxygen in Nitrox, the oxygen becomes toxic when breathed at high pressure. To dive safely with nitrox, the diver must learn good buoyancy control, a vital part of scuba diving in its own right, and a disciplined approach to preparing, planning and executing a dive to ensure that the ppO2 is known, and the maximum operating depth is not exceeded. Reputable dive operators and gas blenders insist on the diver having recognized nitrox training (which appears as an extra notation on a certification card) before selling nitrox to divers.

Nitrox Card

Every nitrox cylinder must have a sticker stating whether or not the cylinder is Oxygen clean and suitable for partial pressure blending. Any oxygen clean cylinder may have any mix up to 100% oxygen inside.

If for some reason an oxygen clean cylinder is filled at a filling station, which does NOT supply gas to oxygen-clean standards, it is then considered contaminated and must be recleaned before a gas containing more than 40% oxygen may again be added. Cylinders marked as NOT-oxygen clean may only be filled with enriched oxygen mixtures from membrane or stick blending systems where the gas is mixed before being added to the cylinder and will not come in contact with 100% oxygen.

The standard nitrox cylinder is yellow in color and marked with a green band around the shoulder of the tank, with "Nitrox" or "Enriched air" marked in white or yellow letters inside( see picture below). Tanks of any other color are generally marked with six inch band around the shoulder, with a one inch green band on the top and bottom, with four inches of green in the middle. This green band will also have the designation of "NITROX" or something similar inside, in yellow or green letters.

Any cylinder containing any blend of gas other than the standard air content is required by the dive community to be clearly marked, however in some parts of Europe a white sticker with Enriched air or Nitrox is used. This is harder to notice and can cause confusion with newer divers. Also all nitrox cylinders should have a tag/ label that states the oxygen content of the cylinder, the date it was blended, the gas blender's name and the maximum operating depth along with the partial pressure this depth was calculated with.
Many training agencies such as PADI, CMAS, SSI and NAUI train their divers to personally check the oxygen percentage content of each nitrox cylinder before every dive. If the oxygen percentage is 1% or more higher or lower than the value written on the cylinder by the gas blender, the scuba diver must either recalculate his or her bottom times with the new mix or else abort the dive to remain safe and avoid oxygen toxicity or decompression sickness. Under IANTD and ANDI rules for use of nitrox which are followed by most dive resorts around the world, all filled nitrox cylinders are signed out personally in a gas blender log book. The log book contains information for each cylinder and it’s mix, the cylinder number, the measured oxygen percent composition, the signature of the receiving diver (who should have personally measured the oxygen percent with an analyzer) and finally a calculation of the maximum operating depth for that cylinder mix. All of these steps minimize the danger, but increase complexity of operations (for example, personalized cylinders for each diver must generally be kept track of on dive boats with nitrox, which is not the case with generic compressed air cylinders).

Diving cylinders are usually filled with nitrox by a gas blending technique such as partial pressure blending or premix decanting (in which a nitrox mix is supplied to the filler in pressurized larger cylinders). A few facilities have begun to fill cylinders with air which has been enriched with oxygen by a pre-mixing process, so that it is pressurized as nitrox for the first time in the diving cylinder. The pre-mixing is accomplished either by a membrane system which removes nitrogen from the air during compression or by a "stick" blending technique where pure oxygen is mixed with air in a baffled chamber attached to the compressor intake.

With the use of pure oxygen during "partial pressure blending" where pure oxygen is added to the nearly empty dive cylinder to 20-35 bar, from a larger pure oxygen cylinder before air is added by compressor. There is an especially increased risk of fire. Partial blending using pure oxygen is often used to provide nitrox for multiple dives on live-aboard dive boats, but it is also used in some smaller diver shops.
There is anecdotal evidence that the use of nitrox reduces post-dive fatigue particularly in older and or obese divers, however the only known study to test this found no statistically significant reduction in reported fatigue. However, there has been some suggestion that post dive fatigue is due to sub-clinical decompression sickness (i. e. micro bubbles in the blood insufficient to cause the symptoms of DCS). This study was conducted in a dry chamber with an ideal decompression profile, which may have been sufficient to reduce sub-clinical DCS and prevent fatigue in both nitrox and air divers.

It is also generally untrue that breathing nitrox can reduce the effects of nitrogen narcosis, as oxygen seems to have an equal amount of narcotic properties under pressure, so you should not expect a reduction in narcotic effects due only to the use of nitrox. For a reduction in narcotic effects Trimix gases which also contain helium are generally used.

Technical use of Enriched air

Nitrox containing 50% to 80% oxygen is however used by many Technical Divers as well as pure oxygen, this eliminates inert gases such as nitrogen and helium from the tissues more quickly than leaner oxygen mixtures eliminate them.

The history of Nitrox

In the 1920s or 1930's Dräger of Germany made a nitrox backpack independent air supply for a standard diving suit. In World War II or soon after British commando frogmen and commercial divers started diving with oxygen rebreathers adapted for semi-closed-circuit nitrox (which they called "mixture") diving by fitting larger cylinders and carefully setting the gas flow rate using a flow meter. These developments were kept secret until independently duplicated by civilians in the 1960s.

In 1959 the United States Navy (USN) documented enriched oxygen gas procedures for military use of what we today call nitrox, in the USN Diving Manual. In 1970 Dr. Morgan Wells who was the first director of the National Oceanographic and Atmospheric Administration (NOAA) Diving Center began instituting diving procedures for oxygen-enriched air. He also developed a process for mixing oxygen and air which he called a continuous blending system. For many years Dr. Wells' invention was the only practical alternative to partial pressure blending. In 1979 NOAA published Wells' procedures for the scientific use of Nitrox in the NOAA Diving Manual.

In 1985 Dick Rutkowski, a former NOAA diving safety officer, formed IAND (International Association of Nitrox Divers) and began teaching nitrox use for recreational diving. This was considered dangerous by some and met with heavy skepticism by the diving community.

In 1992 the name was changed to the International Association of Nitrox and Technical Divers (IANTD), the T being added when the European Association of Technical Divers (EATD) merged with IAND. In the early 1990s, the agencies teaching nitrox were not the main scuba agencies. New organizations, including Ed Betts' ANDI (American Nitrox Divers International), which invented the term "Safe Air" for marketing purposes and Bret Gilliam's TDI (Technical Divers International) gave scientific credence to nitrox.

In 1996, the Professional Association of Diving Instructors (PADI) announced full educational support for nitrox. While other main line scuba organizations had announced their support of nitrox earlier, it was PADI's endorsement that put nitrox over the top as a standard sport diving "option". Then to present day where Nitrox is used on a daily basis, by many recreational divers all around the world!!!!

Is it time you became an Enriched Air Nitrox Diver??