What is your personal "Helium" Depth?

[CAPTAIN SINBAD]

I understand that the DIR community considers anything below 100 feet to be Helium territory. PSAI is the other extreme with their "Narc Management" courses. TDI lies somewhere in the middle with 150 feet to be the limit for Decompression Procedures course. I just wanted to ask tec divers that if you were doing something that involves concentration such as DSLR photography (not the point and shoot but DSLR) or laying a reel etc. at what depth does Helium becomes necessary for you for such tasks?

 

[Jack Hammer]

I've found that at more than 135' narcosis becomes pretty noticeable for me. Even around 120' helium is better for tech dives.

 

[tbone1004]

100' nominal for me, i.e. I can do it to 110 but am not happy about it. I get narc'd really easily and tend to get dark narc'd so I try to avoid it if at all possible

 

[PfcAJ]

I really dig helium deeper than like 80'. 80-100 is 'optional' territory for me.

 

[Kevrumbo]

Use Helium at depth when you need cognitive clarity & N2 Narcosis mitigation while navigating/laying line inside an overhead such as a cave or wreck for example; also use He when you expect physically challenging conditions such as strong currents to work against, in order to mitigate gas density Work-of-Breathing, exertion Hypercapnia & CO2 Narcosis.

Here's a practical example where having a robust easier to breath 18/45 Trimix gave this group of Tech Divers an "error margin" (e.g. CO2 retention moderation and a deeper MOD margin to deal with a strong downcurrent) and note in this incident, no mention of debilitating narcosis:

http://www.scubaboard.com/forums/ne...um-gas-underwater-climbing-drifting-away.html

(What would have happened if they used Air?)

 

[Brandon]

I like the GUE standard gasses and find that they work well for me, both in terms of ease of blending and how I handle them physically.

32% to 100', 21/35 for 100'-150', 18/45 for 150'-200'. Doesn't happen often, but I'd also use 21/35 on a 90-110' square profile dive over 32% nitrox. I don't bother with 30/30.

I'll also dive air when nitrox isn't available, but prefer to not be past 100' or past 70' for any significant amount of time.

 

[PfcAJ]

I like the GUE standard gasses and find that they work well for me, both in terms of ease of blending and how I handle them physically.

32% to 100', 21/35 for 100'-150', 18/45 for 150'-200'. Doesn't happen often, but I'd also use 21/35 on a 90-110' square profile dive over 32% nitrox. I don't bother with 30/30.

I'll also dive air when nitrox isn't available, but prefer to not be past 100' or past 70' for any significant amount of time.

3030 is dope. Give it a shot.

 

[nadwidny]

Like 90% of the tech divers I know and dive with, we are on CCR so we are diving some sort of helium blend all the time. Because we can.

 

[fsardone]

As others have stated CCR gives the freedom to choose to use helium without breaking the bank ... (for the gas equipment wise is another issue).

That said, open water reef dives plenty of vis and benign conditions I dive up to 50 mt in air.
Add overhead (soft or hard) and/or other risk factors (cold, dark, vis) I limit my END to 35-40 mt max.

CCR? dil 16/40 from 35 mt on ... otherwise air.
All of this is not in stone but is my personal reference, it may vary depending on situation.

Cheers

 

[beester]

Depends on circumstances and Kevrumbo already said it best.

- Current or anything which might impact my work of breath (like typically ghost fishing projects, cleaning wrecks, which is hard work, or high flow caves). I want some He in the mix just to avoid CO² buildup. Typically this is 30/30, a bitch to mix but it's a really nice mix for 25-35m (80-110ft) range when you want something easy to breath.
- If I need to have my complete capacity (all cave diving, all wreck penetration, basically all real overhead, which includes more than 15' deco) I'll want to go with a max END of 30m (100ft) and GUE standard gasses.
- If it's not the above I'm comfortable with certain buddies to go to 130ft max on air. Below that all is standard gasses because it is always overhead (I don't bounce dive).

Cheers