0:01
is something that arose out of some I
0:05
assumptions that were made by Buhlmann
0:08
back when he was doing his original
0:11
research and design of his algorithm
0:16
the the physical properties of the
0:19
various gases that he was considering. I
0:22
I think a fair summary of it is to say
0:25
Buhlmann assumed that
0:27
helium would be a faster exchanging gas
0:30
than nitrogen and it's probably best
0:33
just to keep it as simple as that based
0:35
largely on the fact that it's a smaller
0:37
more diffusible molecule and therefore
0:41
you would take up and actually eliminate
0:45
more quickly than nitrogen.
0:48
But what that meant was that on a dive
0:50
where you were breathing
0:52
a substantial amount of helium, you
0:54
would [clears throat]
0:55
build it up in your fast tissues more
0:58
quickly. That would mean that during an
1:01
ascent at the end of your dive
1:05
the [snorts] fast tissues would start to
1:07
reach their Buhlmann super saturation
1:11
earlier than they would have if
1:14
you were breathing nitrogen because
1:15
you've absorbed that helium really
1:17
quickly. So this more rapidly absorbed
1:20
gas would be the limiting gas as you
1:25
And that would mean that you would
1:28
require deeper stops because those
1:31
tissues that had accumulated a lot of
1:32
helium would be reaching their super
1:34
saturation limits more quickly.
1:36
And of course during those deeper stops
1:38
you would be absorbing more gas in the
1:41
slower tissues and that would mean that
1:44
at the other end of your decompression
1:46
the sort of the shallower end you would
1:48
have to spend longer to unload those
1:53
have accumulated more gas during the
1:56
that's where the helium penalty came
1:58
from because you had to stop earlier in
2:01
the ascent because you've absorbed a
2:03
larger quantity of a gas being helium,
2:05
you had to spend more time at the other
2:08
end unloading those slow tissues. And
2:10
that That was the origin of the helium
