TDI and hyperoxic trimix

[BarryNL]

Does one of the TDI trimix courses cover the use of (or provide a c-card for the use of) hyperoxic trimix (e.g. 30/30 for dives to the 36m range). I can only see details of normoxic and hypoxic trimix training.

 

[Tomeck]

Is it a good idea to use helium only for 36 meters? I think not good, because helium is expensive and there is not much narcosis on 36 meters.

 

[BarryNL]

Is it a good idea to use helium only for 36 meters? I think not good, because helium is expensive and there is not much narcosis on 36 meters.

I suppose that depends on whether you're finning along a warm coral reef or making a North Sea wreck dive; I do the latter.

 

[DA Aquamaster]

36m is what? 120ft? With an END of 120' I would not bother with helium - even in a cold, dark, low viz wreck. Using He at that depth strikes me more as conspicuous consumption or perhaps is an after effect of the "I drank too much of the kool-aid" factor, but that's just me.

Given that He is a finite resource and expensive, you could dive a little greener and get a rebreather if you plan on using HE at that depth. Then at least all you are wasting is maybe 10% of what you would waste open circuit.

I am however very interested in why a DIR practitioner would be interested in a TDI course in the first place.

 

[BarryNL]

Given that He is a finite resource and expensive, you could dive a little greener and get a rebreather if you plan on using HE at that depth. Then at least all you are wasting is maybe 10% of what you would waste open circuit.

So, driving a couple of hundred kilometers and an 8 hour round trip on the boat don't really worry you, but using less Helium than a typical children's party does.

Anyway, if you want to save the planet, don't have kids; nothing else makes any realistic difference.

 

[JeffG]

I am however very interested in why a DIR practitioner would be interested in a TDI course in the first place.

Why is that? Perhaps you have been caught making some assumptions.

 

[skippy31]

I'm not aware of any courses that specifically cover hyperoxic trimix, but they do not preclude it either. If your trained on trimix there is really nothing to stop you mixing up 30/30 if you so choose...

Mat.

 

[ppo2_diver]

We used 30/30 for our shallow dives for my trimix class. Shallow being 100-125 feet.

 

[Tomeck]

I suppose that depends on whether you're finning along a warm coral reef or making a North Sea wreck dive; I do the latter.

I often dive on 60 meters (200 feet) in very cold at 4°C (40°F) with air, this is a true narcosis and dangerous. Cold or warm water, it is a same problem for narcosis. I had more narcosis on 50 meters in Palau than on 60 meters in Switzerland, because I was tired of airplane. It is possible to have a important narcosis on 36 meters, when one is very tired, but not often.

 

[captndale]

For those who wish to use hyperoxic trimix, TDI's Intermediate Trimix course covers normoxic and hyperoxic mixes. More to the point, in my thinking, is the question of why you would want to use oxygen as a dilutant gas when you have helium available.