TDI Rebreather Air Diluent (DECO - 45mtrs)

No doubt if you are considering this course, you have already done some research on rebreathers, maybe even had a go or are qualified as a CCR air diluent diver to 30m! The reasons for taking this step are many and varied, but whatever it is that has motivated you to do so, this is the rebreather course that will take you safely into decomplerssion diving using a CCR.

At present, courses are only available on any of the Ambient Pressure Diving series of rebreathers (Classic, Evolution, Evolution Plus, and Vision). Units are available to use for the duration of the course, or we are an authorised dealer for AP Diving and can advise you on and then arrange the purchase of a new unit.


Why TDI Rebreather Air Diluent (DECO - 45mtrs)?

This is a certification course for divers wishing to utilize an Ambient Pressure Diving closed circuit rebreather (CCR) for decompression diving using air as a iluent.

The objective of the course is to train divers in the benefits, hazards and proper procedures for diving a CCR and to develop basic CCR diving skills to a maximum depth of 45 metres / 100 feet, using air as a diluent for formal decompression diving.

Upcoming Courses (back to top)

No courses organised at the moment, please contact us to discuss your requirements.

How do I book myself on a course?

To book yourself on a course please select one of the courses above, send us a message, and we will get back to you to discuss further details.

Further information on TDI Rebreather Air Diluent (DECO - 45mtrs) (back to top)

What do I need to start?

TDI Diving Rebreathers Student Manual AP Valves unit specific instruction manual (available to download from

TDI Decompression Procedures Student Manual 

TDI Advanced Nitrox Student Manual 

TDI CCR Preflight Checklist

What will I do?

The course consists of a minimum of eight hours of theory/knowledge development, accompanied by a minimum of seven open water dives totalling 420 minutes dive time.

There will be a gradual increase in depth of dives over the five days to a maximum of 45 metres. 2 dives will be deeper than 20 metres, and one will be deeper than 30 metres.

Theory covered includes:


  • History of Rebreathers Comparison of OC, SCR and CCR
  • Practical mechanics of CCR
  • Gas physiology
  • Scrubber packing
  • O2 addition systems
  • Dive tables/computers/planning Emergency proceedures


(Pre) Dive skills covered include:


  • Unit assembly
  • Pre dive planning
  • Emergency procedures
  • Loop volume control
  • PO2 monitoring
  • Buoyancy control
  • Use of SMB
  • Safety stops
  • Use/carrying stage cylinders to provide adequate bailout for planned dive.
  • Stage cylinder handling bailout scenarios and oxygen rebreather mode
  • Post dive care/maintenance


How long will it take?

The course requires five days to cover all required material. The courses are usually scheduled to run over five consecutive days (Wednesday-Sunday). Other scheduling options are available (i.e. over two weekends) but we strongly recommend the course is completed over the shortest period possible. The course must be completed within a six week period. Please understand that the course is performance based. This means that certification is only awarded upon demonstration of being capable to conduct rebreather dives. This may involve further training dives beyond the seven required.
CROSSOVER If a student has already qualified as TDI CCR Air Diluent Deco Diver or equivalent from an agency recognized by TDI and wishes to qualify on another CCR recognized by TDI, the student must follow all unit specific course standards except that only 180 minutes dive time required (over three dives and to maximum of 45 metres)

UPGRADES If a student has the TDI Air Diluent CCR Diver (No DECO - 30mt) and wishes to do the decompression part of this course, then only 240 minutes in open water is required The student must also have: minimum of 30 logged hours over 30 dives  and six months CCR diving experience

While not required reading, the following books/articles are recommended reading prior to the course:
  • Richard Pyle - A Learners Guide to Closed Circuit Rebreather Operations 
  • Kenneth Donald - Oxygen & the Diver 
  • John Lamb - Oxygen Measurement for Divers 
  • Barsky, Thurlow & Ward - The Simple Guide to Rebreather Diving 
  • Bob Cole - Rebreather Diving 
  • Jeffrey Bozanic - Mastering Rebreathers
  • Mark Powell - Deco fo Divers

What previous experience do I need?

To enrol on this course students must:

1. Be minimum age 18

2. Provide proof of 50 logged dives

3. Provide proof of TDI Advanced Nitrox Diver and Deco Procedures Diver or equivalent


1. Minimum age 18

2. TDI Air Diluent CCR Diver (No DECO - 30 mt) certified or equivalent

3. 30 hours on the CCR unit

4. Six months CCR diving experience

What do the fees include?

  • All professional tuition 
  • Insurance costs while on the course 
  • TDI Course manual 
  • Use of oxygen analyser
  • 3 fills of sofnolime
  • Diluent gas
  • Fully rigged bailout cylinder
  • TDI certificate upon completion
  • TDI registration upon completion

What don't fees include?

Entry fee to dive site/boat used for the Open Water dives (if applicable)

Costs of transportation to and from dive sites (if applicable)

Any personal costs (eg. food, drink, accommodation)

Oxygen Gas fills

Bailout gas (unless air in early part of course) 


What can I do once I'm qualified?

Upon successful completion of this course, graduates may engage in decompression diving activities utilizing ,a CCR without direct supervision provided:
  • Diluent is air
  • Maximum depth is 45 metres 
  • The diving activities approximate those of training 
  • The areas of activities are approximate to those of training
  • Environmental conditions are approximate those of training

What's next?

Upon successful completion of this course, graduates are qualified to enroll in:


  • TDI Mixed Gas CCR course