TDI Entry Level Trimix Diver Course

The TDI Entry Level Trimix Course provides the training required to competently and safely utilize breathing gases containing helium for dives that require staged decompression, utilizing nitrox and/or oxygen mixtures during decompression to a maximum depth of 200 fsw.

The objective of this course is to train divers in the benefits, hazards and proper procedures of utilizing custom oxygen/helium/nitrogen mixtures as breathing gases.

Prerequisites:

• Minimum age 18.
• Minimum certification as a TDI Advanced Nitrox Diver and Decompression Procedures Diver or equivalent.
• Minimum of 100 logged dives.

Required Course Minimums:

1. Classroom/briefings - 8 hours
2. Open Water Dives - 4 with a minimum accumulated bottom time of 100 minutes, with at least two dives deeper than 130 fsw.
3. Two dives may be credited from the Extended Range course or equivalent at the discretion of the instructor.

Required Equipment:

1. Bottom Mix Cylinders - Cylinder volume appropriate for planned dive and student gas consumption. Dual outlet valve, double manifold with isolator. Labeled in accordance with TDI standards.
2. Travel Mix Cylinder s- Cylinder volume appropriate for planned dive and student gas consumption. Labeled in accordance with TDI standards.
3. Decompression Mix Cylinders - Cylinder volume appropriate for planned dive and student gas consumption. Labeled in accordance with TDI standards.
4. Suit inflation Cylinder - Required for dry suit divers only.
5. Regulators: Primary and primary redundant required on all bottom mix cylinders. SPGs are required on all primary/bottom mix cylinders as well as travel and deco cylinders. A contingency use long hose (7') second stage should be designated and appropriately rigged to facilitate air sharing at depth if necessary. It is strongly recommended that all 4 required regulators be DIN.
6. BCD adequate for equipment configuration.
7. Redundant Depth and Timing devices. Air decompression computers allowed for use as a depth and timing device but you will also need a backup device to this one.
8. Redundant light system as required.
9. Ascent reel with lift bag. Adequate line for planned depth. Minimum 50lb lift bag.
10. Exposure suit adequate for local environment. Dry suit highly recommended in colder waters.
11. 2 line cutting devices
12. Underwater slate(s) 2 for decompression and contingency planning backup.

Required Subject Areas:

The following topics must be covered during this course. The TDI Trimix Manual is mandatory for use during this course but instructors may use any additional text or materials that they feel help present the topics.

1. Physics - Pressure review.
2. Physiology- Hypoxia, oxygen toxicity (whole body and CNS), nitrogen narcosis, nitrogen and helium absorption and elimination, carbon dioxide toxicity, carbon monoxide toxicity. Helium specific: HPNS, effects on respiration, effects as an insulator. Counter diffusion hyperthermia, hypothermia.
3. Decompression Options - Air, Nitrox, Helium.
4. Equipment Considerations: cylinder options, stage cylinders options, suit inflation options, regulator options, harness/BCD options, Computer, depth gauge/bottom timer options, Ascent and navigation reels, lift bags and surface marker buoys, lighting, redundant mask and knife, jon-line.
5. Dive Tables - Computer generated tables. DCIEM Heliox Tables and/or other published tables.
6. Dive planning - Operational Planning- support, teams
7. Team Planning - Gas requirements, oxygen and nitrogen limitations.
8. Emergency Planning - Omitted decompression, oxygen toxicity, analysis and logging, general.
9. Procedures - Bottom, travel and decompression gas- Normal operations, failure, loss or inadequate emergency procedures. Analysis and logging.

1. Properly analyze all gas mixtures to be used and label cylinders accordingly.
2. Demonstrate adequate pre-dive planning:
   1. limits based on personal and team gas consumption
   2. limits based on oxygen exposures at planned depths for actual mixes.
   3. limits based on inert gas absorption at planned depths with actual mixes.
3. Properly execute the planned dive within all pre-determined limits.
4. Demonstrate proper navigational techniques for the specific dive.
5. On two of the dives, demonstrate an ascent with ascent reel and lift bag. Perform staged decompression.
6. Demonstrate the proper procedures for switching and isolating a malfunctioning primary reg. (This exercise not to be performed deeper than 130 fsw.)

Graduation Requirements:

1. Satisfactorily complete the TDI Trimix Course written exam
2. Complete all open water requirements safely and efficiently.
3. Demonstrate mature, sound judgment concerning dive planning and execution.

Support Materials:

TDI Trimix manual

Tuition: $1195.00 plus fees for boat dives. Trimix and nitrox over 40% are extra.