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.
•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.
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.