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We have a wide variety of dive locations for technical diving expeditions.

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Tech Asia offers many technical diving courses for experienced divers and aspiring instructors.

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Trimix Courses – What’s in a name ?

IANTD Trimix courses have been an integral part of what we do at Tech Asia for many years.  Not just the ‘full’ trimix courses that exist to cover the very deep range, where you really don’t have much choice, but the lower level  trimix courses that cover the use of the gas from about 40m on down,  have been something that IANTD, and ourselves, have long since embraced.
The terminology can be a bit confusing to the uninitiated ( with IANTD and with other agencies too ) but the various courses we can provide are overviewed here  and we’ll try to give a breakdown below of what’s involved and what they all mean.
Technical diving, like recreational diving or any other skills based sport for that matter, is taught in steps designed to take the participant to higher levels of achievement as their experience and training level increases.  In all honesty it would simplify life if the steps were just called Trimix Diver 1, 2 and 3…but most agencies syllabus didn’t evolve that way.

Historical Background to Trimix diving

Here’s how it happened. In the early years of technical diving, accepted practice was to use air down to 50 or 60m and then trimix thereafter.  Hence in most agencies, all that existed was one course, ‘Trimix Diver’ for the 60-90m stuff. This goes right back to the days when helium based gases were less well understood than now, and thought  to be the source of all manner of problems from thermal issues to decompression difficulties, and thus to be avoided unless absolutely necessary.
As divings’ pioneers and explorers developed the sport, and furthered our understanding of helium based gas blends, it became clearer and clearer that diving trimix shallower than conventional wisdom had previously suggested would only improve matters, and under almost no circumstances cause any trouble.
Now with a greater acceptance of the utility of trimix came a position for another course, something to provide an alternative to the traditional deep air pathway, courses like IANTD Technical Diver, or TDI Extended Range. The course format was pretty easy to devise – keep it the same as Technical Diver but use trimix instead of air. It really was almost that simple, requiring the same skill set, same gas management rules, same oxygen considerations, same way of applying decompression software…but what to call it?

Normoxic Trimix Diver appears

IANTD decided on Normoxic Trimix Diver.  Why, and what does that mean? Well, Normoxic implies a gas that is 21% oxygen, plus or minus a per cent or so, just like air. And for the target depth range of this course, no more than 60m, this allows your trimix bottom gas to be safe to breathe from the surface all the way on down. That is something that isn’t necessarily the case with deeper dives where in order to have a safe partial pressure of oxygen at maximum depth, the trimix used may need to have quite a bit less than 21% oxygen. This might not be safe to use at the surface or very shallow water as it can cause

the diver to lose consciousness due to hypoxia, in other words not enough oxygen, and needs the diver to use what is termed a travel gas for their descent.  Normoxic Trimix avoids all of that and makes life operationally simple because of it.
Where some people overthink matters and believe these courses reference two different types of trimix, in reality, trimix is trimix and the courses merely address different depth ranges and complexity of dive. One gas blend has a bit more oxygen, but that’s really all there is to it. See page on IANTD Normoxic Trimix

Entry Level Training Courses

Fast forward about three more years and in line with some of the more cutting edge exploration practices, some parts of the industry, IANTD amongst them, recognized that there was a place for a trimix course in the entry level range of technical diving.  Relatively speaking this is a simple range of diving, not to deep, single decompression gas and so on, but not all of the world dives in benign conditions where air is good enough. Introduce heavy currents, dark water, silty wrecks, dives with complex tasks to be performed, and this change of thinking on gas mix all begins to make good sense.
Like Normoxic and Technical Diver before it, this new course was to be an alternative to an Advanced Nitrox course, rather than something that you had to do in addition to it. Again the format was the same bar the use of the gas, and a depth rating of 48m instead of 42m because of it, IANTD now launched its Advanced Recreational Trimix Diver course.  A bit of a mouthful and perhaps a misnomer since it really is a technical diving course and not a recreational one, but we have what we have, and importantly it created an excellent progression of training delivering all the skills and know how, along with the most useful gases for the new tech diver right from the very beginning should they choose to take advantage of it.
Would something like Trimix 1, 2 and 3 be more intuitive? Maybe it would, but since as you see the IANTD courses were introduced from the top down that wasn’t destined to happen.  


Trimix at depth



Nitrox and trimix diving courses with Tech Asia.



Trimix or nitrox?


Trimix courses teach a lot