TDI –  Nitrox Diver Course

This course can be combined with Advance Nitrox

Options:
1.  1/2 day to 1 day academics and surface work only with no dives
2.  1 academics and 2 supervised dives

Introduction
This is the entry-level certification course for recreational divers wishing to utilize enriched air Nitrox (EAN) as a breathing gas. It can be taken as a half day to one day "academics only" course  or together with optional, supervised, two dives.

The objective of this course is to train certified divers in the benefits, hazards, and proper procedures for using Nitrox mixes from twenty two (22) to forty (40) percent oxygen content.

Qualifications of Graduates
Upon successful completion of this course:
1. Graduates may engage in diving activities utilizing EAN-22 to EAN-40 without direct supervision.

Graduates would be qualified to enroll in:
1. TDI Advanced Nitrox Course.
2. TDI Decompression Procedures Course.
3. TDI Semi-closed Rebreather Course.

Open Water (Ocean, lake, quarry, spring, river or estuary):
1. Since entry level Nitrox is essentially an information and academic based course, no dives are specifically required as there are no skills to evaluate.

2. However, optional dives are desirable to effectively demonstrate the advantages of EAN use in practical field use. If scheduled, no direct instructor supervision is required but dives should not be conducted in environments that may exceed the existing skill or depth levels of the student.

Student Pre-Requisites
The student must:
1. Be a minimum age of fifteen (15).
2. Have a Minimum certification of Open Water Diver or a current enrollment in an Open Water Diver course.

Open Water Execution:
Two (2) Nitrox dives are recommended but are not required.

TDI Medical Statement

TDI Technical Diver Registration Form

TDI Liability Release & Express Assumption of Risk

Some Questions and Answers on Diving using Nitrox

What is Nitrox?

This lets divers to breathe comparatively less nitrogen on all dives, increasing their bottom time and/or increasing their safety limits when compared to air diving. It is not a "Devil Gas" but a breathing mix of contemporary and future diving. One agency refers to it as "Safe Air" while others regard it simply as Nitrox. 

How does Nitrox Work?

The most common EANx mixtures throughout the world are 32 and 36 percent, meaning 32 or 36 percent Oxygen in the mix. In normal air, there is 21% Oxygen and 79% Nitrogen (ignoring the 'trace' gases). In a 32% mix, the amount of nitrogen is down to 68% whereas in a 36% mix, it is further lowered to 64%. Lowering the Nitrogen content makes our body intake less Nitrogen at given depths. Our body 'feels' it is at a shallower depth and the no-decompression limits for that shallower depth are used to set the bottom time. If a diver was doing an "air" dive to 24 metres, he/she would use a 24metre dive table . Using Nitrox 36 to this depth though, the diver can run a dive according to its "Equivalent Air Depth" of 17.5 or 18 metres. Hence the extra bottom time. 

Who can dive Nitrox? 

According to the TDI standards, any diver from Open Water Diver upwards may take the TDI Nitrox Course. Only certified Nitrox divers may purchase nitrox from dive centres. 

Can Nitrox be used at depth?

The lower partial pressure of Nitrogen in the breathing mix is the trick. The difference in bottom times in the 20-35 metre range when compared to air diving is notable, increasing the no-decompression limits. But, the deeper a diver goes, the less significant this difference becomes. Nitrox can be used to a depth where the partial pressure of Oxygen is within safe limits. but divers should still take into account the potential for nitrogen narcosis. Although divers dive to a certain depth, the lowered rate of Nitrogen makes the body perceive this as being a shallower depth when compared to diving air. 

Do I need special equipment?

No, not really. Basic nitrox courses offered by various agencies such as PADI, BSAC, TDI and IANTD allow divers to use a 'bottom gas' ranging from 22 to 40 percent Oxygen at maximum. Unless otherwise specified by the manufacturer, using up to 40% O2 in the breathing medium in Britain does not require special equipment. Generally speaking normal air regulators and pressure gauges can be used without modification unless the manufacturer . This is because regulators, BCDs, LPIs and SPGs never come in contact with high levels of "pure" Oxygen. 

Do I need "Oxygen Serviced" cylinders?

Yes, in the United Kingdom you do. General practice in British diving operations is to "partial pressure blend" your mix. In other words, unlike in some American states, we do not use "premixes." Dive centres have to prepare tailor-made mixes for divers which involves filling the tanks first with 100% Oxygen to a calculated limit and then "top it off" with air to get the right mix. At this stage your cylinder and valve come in contact with 100% Oxygen. Oxygen, in contact with hydrocarbons such as silicone grease, could lead to problems. Because of this your cylinder, valve, o-rings and other components will be cleaned of any 'contamination' while all oils are replaced with O2 friendly greases. From then onwards, you will need to make sure your bottle is "Oxygen Serviced" every year.