Heliair???

[Narked_at_60]

Hi, does anyone know what heliair is?

 

[Albion]

Hi, does anyone know what heliair is?

Fill tank half full of air, then fill rest of way with helium, or vice versa, not sure the exact protocol here
10.5% O2
39.5% N2
50% He
no need for special blending equipment, but does not support life at surface

 

[ninjamuzo]

HeliAir is a mixture of Helium and Air. The idea is to mix Air with Helium until you have the O2 percentage you are after. If you select bottom mixes that can be mixed in this way it makes it very easy to top up Trimix tanks on a boat for example.

The percentage of Helium in the mix will vary depanding on the desired O2 percentage. The mix described above is one such result.

 

[roakey]

I wrote up a fairly complete description in this note awhile ago:

http://www.scubaboard.com/t5306.html

Roak

 

[wedivebc]

I wrote up a fairly complete description in this note awhile ago:

http://www.scubaboard.com/t5306.html

Roak

Nice report Roak. I would like to add one comment though.
Even though air is a great gas for breathing on land, the ratio of 21%/79% is less than ideal for diving and as depth increases the shortcomings become more apparent. Heliair, by virtue of containing this same ratio will not contain ideal mixes for any depth.


cheers,

 

[Doppler]

Hi, does anyone know what heliair is?

Historically referred to as "Poor man's Trimix." which though somewhat sexist is a pretty sound definition... easy and dirty way to mix with a resulting gas that delivers generally poor balance between CNS and Narcosis management.