ABOUT THE COURSE
This Technical Diving International’s course introduces mixed gas diving on a closed-circuit rebreather (CCR) and marks a significant expansion of operating range. It’s where helium becomes part of your dive planning and CCR diving moves into deeper, more complex environments.
You’ll learn to conduct CCR dives using helium-based diluent, managing narcosis, gas density, and decompression with greater precision. Training focuses on maintaining control as depth increases, task loading grows, and dives require more detailed planning and execution.
WHO IS THIS COURSE FOR
This course is for certified CCR divers who have already completed air diluent decompression training and are ready to extend their depth capability.
PREREQUISITES
To apply for this course you must meet the following criteria:
- Minimum age: 18
- TDI CCR Air Diluent Decompression Diver or TDI CCR Helitrox Diluent Decompression Diver (or equivalent)
- Minimum 50 hours on a rebreather, across at least 50 dives
NOTE: If transitioning from another TDI-recognized CCR unit, a minimum of 25 hours must be on the unit used for training.
WHAT YOU'LL LEARN
Theory and system knowledge
- Mixed gas physiology, including helium absorption and HPNS
- Oxygen exposure management, CNS and OTU tracking
- Equivalent narcotic depth planning and diluent selection
- Gas management and bailout planning for deeper dives
- CCR system configuration and maintenance for mixed gas use
- Dive planning using constant PPO₂ decompression models
- Use of dive computers and planning software for mixed gas CCR dives
In-water skills and training
Training includes confined water sessions and open-water dives conducted at greater depth, with increased task loading and team coordination.
You will practice:
- Mixed gas CCR dive planning and execution
- PPO₂ control and setpoint management throughout the dive
- Managing multiple bailout cylinders
- Responding to system failures at depth
- Conducting staged decompression on mixed gas
- Lift bag / DSMB deployment during ascent and decompression
- Stable buoyancy and precise loop volume control
- Post-dive unit care and maintenance
WHAT’S IN IT FOR YOU
After successful completion, you will be certified to:
- Conduct mixed gas CCR dives
- Dive to a maximum depth of 60 metres / 200 feet
- Use helium-based diluent with oxygen content as low as 16%
- Dive independently within conditions similar to those encountered during training
- Progress to Advanced Mixed Gas CCR Diver training
COMPLETION REQUIREMENTS
To complete the course, you must:
- Demonstrate all required confined and open-water skills to instructor satisfaction
- Show sound judgment in dive planning, execution, and failure management
- Meet all unit-specific and manufacturer requirements
A refresher is required after extended periods of inactivity, in line with TDI standards.
WHAT CCR MANUFACTURES ARE RECOGNIZED BY TDI?
TDI programs are recognized by a number of CCR manufactures worldwide. TDI is also member of RESA and is actively involved in the development of training standards. Below are the closed-circuit rebreather manufacturers that TDI and Ocean Explorers currently work with, along with letters of approval from each manufacturer.