Nitrox Certification

Tanks without the proper nitrox or enriched air 6-inch band designating them as nitrox cylinders

Enriched air or "nitrox" certification is a specialty scuba diving certification that can be done after a diver has first been certified as an open water diver. Enriched air is any air that has been enriched with oxygen. Enriched air nitrox is one of the latest tools used by divers to be able stay underwater for longer periods of time.

Types

For the purposes of recreational scuba diving, enriched air nitrox contains more oxygen (the two most popular blends are 36 or 40 percent) and less nitrogen (60 or 64 percent) than diving on plain old air (21 oxygen and 79 percent nitrogen). According to the PADI Enriched Air Diving Manual, the name "nitrox" may be capitalized when referring to specific mixtures such as Nitrox36, which contains 36% oxygen and 64% nitrogen

Considerations

Since enriched air has higher oxygen contents than air, divers have special procedures for managing the risks related to breathing in a higher oxygen content while diving. After being certified as an Open Water Diver through a diving course offered by the various diving associations (PADI or NAUI are the two most common ones), a diver must take a specialty course to learn how to dive with nitrox.

Requirements

According to the PADI Enriched Air Diving Manual, the course requirements include the purchase of educational materials, classroom training and two open-water dives while breathing in nitrox. Classroom training teaches the benefits and risks associated with breathing nitrox and the diving portion teaches how to analyze oxygen content and then dive with the specialty cylinders filled with the enriched air blend. Classroom training is one four-hour class followed by the two open-water dives.

Equipment

According to the PADI Enriched Air Diving Manual, regulators, BCDs and alternate air sources purchased at a recreational dive shop are suitable for nitrox breathing and may be used with nitrox that have up to 40 percent oxygen blends. Scuba cylinders must be marked with a band reading enriched air, enriched air nitrox or nitrox, along with the percentage of nitrox, the maximum depth for the blend, the fill date, and who analyzed the oxygen content.

Significance

Once you are nitrox certified, you are able to dive breathing nitrox wherever nitrox diving is offered. It is one of the many specialty certifications offered by the diving associations. You receive a certification card, the same as for the Open Water Diver certification. This certification allows you to dive under the in water supervision of a Divemaster or someone with a higher level professional rating, applying the knowledge and skills you learned in the nitrox course.

Warning

The PADI Enriched Air Diver Manual warns that the biggest risk associated with breathing nitrox is oxygen toxicity. If you make a mistake and exceed the depth limit of enriched air, the possible consequences are more hazardous than with air . The primary oxygen toxicity concern is Central Nervous System toxicity that may cause a diver to convulse. Warning signs include visual disturbances tunnel vision, ear ringing, nausea, muscle spasms or dizziness.

Prevention/Solution

Used properly, enriched air has good safety records. Always apply steps that make tangible sense when diving, including making safety stops, maintaining a proper ascent rate, and avoiding predisposing decompression illness factors such as dehydration or excessive alcohol consumption.

References

• "PADI Enriched Air Diving Manual"; PADI; 2004
• "PADI Open Water Diver Manual"; PADI; 2003

Resources

• PADI Enriched Air Diver
• NAUI Enriched Air Nitrox Diver