TDI Mixed Gas CCR Diver


This is the intermediate level certification course for divers wishing to utilize a closed circuit rebreather (CCR) for mixed gas diving. The objective of the course is to train divers in the benefits, hazards and proper procedures for mixed gas diving on the unit specific CCR, utilizing a mixed gas diluent containing helium and 16 percent or greater oxygen, and to develop intermediate CCR diving skills appropriate to technical diving to a maximum depth of 60 metres / 200 feet.



Class Duration:  Minimum of 6 hours academic development and 2 hours equipment maintenance workshop. The duration of the entire course must take a minimum of 5 days.



Course Structure

Open Water Execution 

1. Open water drills practice air diluent dive and 50m fully-equipped CCR diver surface tow must be completed prior to conducting mixed

    gas diluent training dives 

2. Minimum of 360 minutes open water training to be completed over a minimum of 6 dives including 1 equipment configuration

    and drills practice air diluent dive to a maximum 40 metres / 130 feet and a minimum 60 minute duration. 

3. All subsequent dives to build incrementally in no greater than 10 metres / 33 feet steps

4. A minimum of 5 dives must be conducted on mixed gas diluent. 

5. All mixed gas dives are to be deeper than 40 metres / 130 feet, utilizing a mixed gas diluent containing 16 percent or greater oxygen,

    to a maximum depth of 60 metres/200 feet 

6. A minimum of four dives must be decompression dives. At least two dives should be deeper than 50 metres/165 feet and at least one

    dive must have a total run time greater than 60 minutes. Decompression obligation for the first two decompression dives must not

    exceed 30 minutes, and for the third and subsequent decompression dives, must not exceed 60 minutes.



Student Prerequisites

1. Minimum age 18 

2. Provide a verified log of a minimum of 50 rebreather hours distributed over a minimum of 50 dives on the specific rebreather. Valid

    logged divesmust be deeper than 9 metres / 20 feet, at least 20 must be deeper than30 metres / 100 feet, and at least 10 dives

    requiring staged decompression. If the diver has 50 hours on another CCR unit recognized by TDI, only 25 hours/25 dives are required

    to be on the specific unit. If completing a unit crossover, provide proof of at least 10 logged CCR dives in the last 12 months. 

3. Certified as a TDI Air Diluent Decompression Procedures Rebreather/ TDI CCR Helitrox Diluent Decompression Procedures Diver course

    or equivalent from agencies recognized by TDI



Required Equipment:  

The following equipment is required for this course:

1. TDI Diving Rebreathers Student Manual or eLearning 

2. TDI Diving Rebreathers Instructor Guide 

3. TDI Extended Range and Trimix Student Manual or eLearning 

4. TDI Extended Range and Trimix Instructor Guide 

5. TDI CCR Preflight Checklist 

6. TDI Diving Rebreathers PowerPoint Presentation 

7. Unit specific rebreather manual 

8. Unit specific rebreather examination if required by the manufacturer 

9. Manufacturer’s Build Checklist 

10. Manufacturer’s manual and updates 

The following equipment is required for each student: 

1. A complete closed circuit rebreather configured within the manufacturers recommendations; this should be the student’s personal

2. One (1) CCR mixed gas computer and 1 backup OC/CCR computer for bailout in the event of a system failure 

3. Bailout gas cylinders (minimum 2) with the appropriate capacity for the planned dive, each equipped with a first and second stage and


4. Mask, backup mask, fins and a suitable line-cutting device 

5. Slate and pencil 

6. Reel with a minimum of 60 metres / 200 feet of line 

7. Reel with a minimum of 30 metres / 100 feet of line 

8. Two lift bags / delayed surface marker buoys (DSMB’s) with adequate lift and size for the dive environment. Required for open water

    environments only. 

9. Exposure suit adequate for the open water environment where training will be conducted 

10. Access to an oxygen analyzer 

11. Access to a helium analyzer 

12. Adequate weight

Note: The instructor and any certified assistant will also carry a bailout gas supply during all open water sessions. This redundant gas source must be greater than the instructor and any certified assistant’s bailout requirements.

Total  Cost: $1800 (Includes E-learring and certification card upon course completion; Does not including required gear)

Rental of a rebreather is available upon request.

Scroll to Top