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As your motivation to explore progresses you will find that you may want to go deeper to dive that wreck that is part of history or that cave system that you have read so much about.  One of the major limiting factors of going deeper is narcosis; TDI’s Trimix Diver course shows how to minimize the effects of narcosis by adding helium to offset the nitrogen in your breathing gas. While taking the Trimix Diver course your TDI Instructor will teach you how to plan and execute dives utilizing as little as 18 percent oxygen and diving to maximum depth of 60 m/200 feet with a blend of helium appropriate for the planned depth. The course covers topics and skills like
The following equipment is required for each student:
1. Bottom mix cylinder(s)
a. Cylinder volume appropriate to complete all planned decompression on bottom mix
b. Dual outlet valve, double manifold or independent doubles
c. Labeled in accordance with TDI Standards
2. Decompression mix cylinder(s)
a. Cylinder volume should contain a minimum of 1.5 times the gas required for the planned
b. Labeled in accordance with TDI Standards
3. Suit inflation cylinder, required for dry suit divers only
4. Regulators
a. Primary and primary redundant required on all bottom mix cylinder(s)
b. Submersible pressure gauges are required on all primary / bottom mix cylinders
c. A contingency use long hose second stage should be designated and appropriately rigged to
facilitate air sharing at depth if necessary
d. It is strongly recommended that the 3 required regulators be all DIN or all yoke
5. Buoyancy compensator device(s) (BCD) adequate for equipment configuration
6. Redundant depth and timing devices
7. Air decompression computers are allowed for use as depth and timing devices, provided they have a gauge
8. Redundant light system if required by site
9. Ascent reel with lift bag/surface marker buoy
a. Adequate for maximum planned depth
b. Minimum of 23 kg / 50 lb lift bag; a dump valve highly recommended
10. Exposure suit adequate for the open water environment
11. Line cutting device
12. Underwater slate, (for decompression / contingency tables
13. Helium analyzer, recommended
Required Subject Areas
The TDI Extended Range Entry Level Trimix Manual is mandatory for use during this
course but instructors may use any additional text or materials that they feel help present
these topics. The following topics must be covered during this course:
1. Physics
a. Pressure review
2. Physiology
a. Hypoxia
b. Oxygen (O2) toxicity
i. Whole Body (OTU’s)
ii. Central nervous system (CNS)
c. Nitrogen narcosis
d. Nitrogen and helium absorption and elimination
e. Carbon dioxide (CO2) toxicity
f. Carbon monoxide (CO) toxicity
g. Helium
i. HPNSii. Effects on respiration
iii. Effects as an insulator
h. Counter diffusion
i. Hyperthermia
j. Hypothermia
3. Decompression Options
a. Air
b. Nitrox
c. Helium
4. Equipment Considerations
a. Cylinder options
b. Stage cylinders options
c. Suit inflation options
d. Regulator options
e. Harness / BCD options
f. Computer / depth gauge / bottom timer options
g. Ascent and navigation reels
h. Lift bags/surface marker buoys
i. Lights
j. Redundant mask and knife
k. Jon-line
5. Dive Tables
a. Computer generated tables
b. DCIEM Heliox Tables or other published tables
6. Dive Planning
a. Operational planning
i. Support
ii. Teams
b. Team planning
i. Gas requirements
ii. Oxygen limitations
iii. Inert gas limitations
c. Emergency planning
i. Omitted decompression
ii. Oxygen toxicity
iii. Analysis and logging
iv. General
7. Procedures
a. Bottom, travel and decompression gas
i. Normal operations
ii. Failure, loss or inadequate emergency procedures
iii. Analysis and logging
Required Skill Performance and Graduation Requirements
The following open water skills must be completed by the student during open-water dives.
It is recommended that all dives be conducted between 30 metres / 100 feet and 60 metres /
200 feet. Gas mixes are not to have any less than 18 percent oxygen (O2).
1. Skills review from previous TDI skills requirements
Land Drills
1. Demonstrate familiarity with basic and intermediate hand signals
2. Select and prepare equipment suitable for soft overhead environment with long decompression obligations
3. Conduct team oriented drills for lift bag deployment and gas switching procedure
4. Drills for buddy rescue
5. Properly analyze all gas mixtures to be used
6. Demonstrate adequate pre-dive planning
a. Limits based on personal and team gas consumption
b. Limits based on oxygen exposures at planned depths for actual mixes
c. Limits based on inert gas absorption at planned depths with actual mixes
Pre-dive Drills
1. Use START* before every dive
2. Stress analysis and mitigation
*START is S-drill (OOA drill and Bubble Check), Team (buddy equipment checks), Air (gas matching),
Route (entry/exit and planned path underwater), Tables (depth, duration, waypoints and schedule).
In-water Drills
1. Show good awareness of buddy and other team members through communications, proximity and team oriented dive practices
2. Demonstrate competence managing 2 stage cylinders, either 2 deco gas or 1 deco and 1 extra bottom gas,
including drop and recovery while maintaining position in the water column
3. Demonstrate ability to confirm gas switches at depth with buddy/team members
4. Demonstrate lift bag deployment from depth and use of bag as back-up buoyancy device
5. Demonstrate air-sharing ascent from depth while one member of buddy team is without mask
6. Create contingency decompression schedule after simulated loss of decompression gas
7. Demonstrate controlled ascent with toxed diver including surface tow at least 30 metres / 100 feet with
equipment removal on surface, in water too deep to stand in
8. Complete a horizontal breath-hold swim at depth for 15 metres / 50 feet with mask off or blacked out
9. Properly execute the planned dive within all predetermined limits
10. Demonstrate the proper navigational techniques for the specific dive
11. On 2 of the dives, demonstrate an ascent with ascent reel and lift bag and perform staged decompression
12. Demonstrate the proper procedures for switching and isolating a malfunctioning primary regulator This exercise should not be practiced deeper than 40 metres / 130 feet
13. Demonstrate buoyancy control; ability to hover at fixed position in water column without moving hands or
In order to complete this course, students must:
1. Satisfactorily complete the TDI Trimix Course written examination
2. Complete all open water requirements safely and efficiently
3. Demonstrate mature, sound judgment concerning dive planning and execution

Standard TDI Extended Range & Trimix Student Kit

Certain areas of the world provide spectacular dives at depths deeper than 39m/130 feet but you will not have access (or very limited access) to helium. The TDI Extended Range course teaches you the proper techniques for utilizing compressed air as a breathing gas and with a maximum depth of 55m/180 feet you won’t have to miss those dives.

As your motivation to explore progresses you will find that you may want to go deeper to dive that wreck that is part of history or that cave system that you have read so much about. One of the major limiting factors of going deeper is narcosis; TDI’s Trimix Diver course shows how to minimize the effects of narcosis by adding helium to offset the nitrogen in your breathing gas.This is perfect combo. 
This item features the Standard materials needed for a student to take the Extended Range & Trimix certification course online.

This Item Includes:
• SDI Student Presentation Bag
• TDI Logo Sticker
• TDI Student Record Folder
• TDI Extended Range & Trimix Manual
• TDI Temporary Card