what is trimix?

[kubefish]

i have been hearing the term trimix lately
what is it? and what is it used for?

 

[Green_Manelishi]

"trimix" GENERALLY refers to a He/O2 mix to which AIR
(because it is free) has been added. Therefore it is
Helium-Oxygen-Nitrogen (discounting trace gases in air)
mixed in proportion to how deep the dive is planned.

it is used in order to reduce the nitrogen (and oxygen) narcosis effect of diving on air or EAN. It is also used to reduce the risk of O2 toxicity of deeeeep diving. Be aware that use of He brings in its own set of variables and it
is not inexpensive.

 

[kubefish]

"because it is free" that is funny!

 

[Green_Manelishi]

you COULD add pure Nitrogen to your He/O2 mix. You'ld have trimix for sure but you'd be paying for the Nitrogen and
that would be rather silly considering that air contains
plenty of it for use.

FWIW you could use He/o2 (heliox) rather than "trimix"
but the added He is added $$$. making "trimix" you can
keep the END (equivalent narcotic depth) of the Nitrogen
to 100 feet or shallower and save yourself a quid or two.

 

[100days-a-year]

kubefish,see the icon to the right ,thats what you look like on air.Narcosis from increased partial pressure of nitrogen gets rather extreme at depths beyond 130' to 150'.Tri-mix is used for diving beyond these depths.It's really not that expensive 30 to 60 cents a cu ft for the helium.Call it 25 to 60 dollars for a 250 ft 30 min bottom time.Then add air and o2 for the mix plus deco gasses say 35 to 80 for the above dive.But diving ain't for the cheap---it is a vice as much as a hobby.p.s. Don't try it till your comfortable with lots of classtime and new equipment expenditures.

 

[detroit diver]

G_M & 100 days-

What are the basic depth rules for using EAN and Trimix? Isn't EAN basically a shallow water mix?

Just curious.

 

[Atomox]

Detroit

A basic guideline for EANx is:
1.4 ATA PPO2 for diving
1.6 ATA PPO2 for Deco

for Trimix you need to balance a number factors, such as depth and exposure and the environment that you are in to come up with the correct mix.

again general guidelines:

1.0 to 1.4 ATA PPO2,
EAD of 100 feet (I use 90 to 75)

Brad

P.S.

Eric for the curious:
Stadium Pal sizer
http://www.stadiumpal.com/sizer.htm

 

[detroit diver]

Atomox,

Thanks for the info, but I guess I'll have to learn what the ATA numbers mean for it to make sense.

 

[Ladydiver]

Hey Eric and Atomox,

Now what I want to know is how is it that you guys have all of these links...

On second thought, I don't think I really want to know.

 

[IndigoBlue]

When you mix helium with EAN36 do you still call it trimix?

Or does it then go by heli-trox?

I know you still mark the tanks with XX/XX/XX for O2/He/N2.

But I don't know what you call it then.