Requiring shallow helium mixes?

[northernone]

With the research in gas densities and narcosis being significant at shallower depths then historically considered what is your personal minimum depth where helium becomes a reasonable necessity for your dive plan? How deep a dive would you cancel and not dive if helium was unavailable? Side note: recognizing conditions, availability and cost also dictate this decision. Making a meaningful poll factors are limited. Assume 'normal' conditions for you.

Rough poll attached. Also curious what has helped form your current assessment.

Regards,
Cameron

 

[DustyC]

I voted 160, but I'm still a tech student with basically no deep experience. So my opinion is basically worthless.

 

[_Ralph]

Bit of a loaded answer for your simplish question .... and no answer that I see that applies to me....


Assuming a 'recreational' technical dive (i.e. just looking at depth as the factor) than anything beyond 30m/100ft, however a lot of my tech dives are working in the 24-30m/80-100ft range, where the addition of Helium is very much appreciated ....

In the event that Helium isn't available, or priced in such a way to be financially irresponsible, then I have gone deeper (if warranted) on lesser nitrox mixes, but those are usually recreational dives (no deco)


_R

 

[Kevrumbo]

With the research in gas densities and narcosis being significant at shallower depths then historically considered what is your personal minimum depth where helium becomes a reasonable necessity for your dive plan? How deep a dive would you cancel and not dive if helium was unavailable? Side note: recognizing conditions, availability and cost also dictate this decision. Making a meaningful poll factors are limited. Assume 'normal' conditions for you.

Rough poll attached. Also curious what has helped form your current assessment.

Regards,
Cameron

If Helium wasn't available for depths of 40m and beyond, then I would at least utilize a DPV/Scooter to provide all mobility and minimize the work-of-breathing & prevent exertion CO2 retention/Hypercapnia of using Deep Air, especially if you anticipate working against strong currents at those depths. (Gas Density of Air at 40m is 6 g/L)

MOD ranges of
UTD Standard Mixes @ 1.2ATA ppO2:
Eanx32: 28m
25/25: 38m
21/35: 47m
18/45: 57m
15/55: 70m
12/60 (or 10/70): 90m
10/70: 110m

So at a bottom gas working ppO2 of 1.2 ATA, the END of the Standard Mixes list above are all at 30m or less and with Gas Densities less than 6 g/L.

 

[Compressor]

This poll is of special interest to many divers who are not or don't want to be tech divers but want to dive between 100-130 feet and are facing nitrox's diminishing returns.

 

[RainPilot]

This poll is of special interest to many divers who are not or don't want to be tech divers but want to dive between 100-130 feet and are facing nitrox's diminishing returns.

Definitely. There seems to be an unexpectedly high demand for recreational helium. RAID has just released their deep speciality with trimix option.

 

[doctormike]

If Helium wasn't available for depths of 40m and beyond, then I would at least utilize a DPV/Scooter to provide all mobility and minimize the work-of-breathing & prevent exertion CO2 retention/Hypercapnia of using Deep Air, especially if you anticipate working against strong currents at those depths. (Gas Density of Air at 40m is 6 g/L)

Yup!

Diving with Stevie Wonder

 

[rgdiver1]

If diving to 100 feet or below, I would add helium. If helium wasn't available, I wouldn't do the dive. I've been narced enough times when switching to nitrox at 120 feet after being on trimix at depth to make up my own mind that deep air is not a good thing.

 

[Tug]

Locally (Massachusetts) OC my limit is aroind 120ish and on CCR it's usually always.

 

[Capt Jim Wyatt]

When diving my O2ptima CCR, (or any other)I use helium on most all dives deeper than 60 feet primarily to reduce the work of breathing.