[Date Prev][Date Next] [Chronological] [Thread] [Top]

Re: [PSUBS-MAILIST] New means having alot to learn.



Hi,

>BTW, is it possible to "prep" for a dive by placing yourself in a
>zero-nitrogen environment?  If so, how?
>Carl

It's possible to use helium/oxygen breathing gas mixture. However, you will 
_still_have_to_decompress_ (only now it will be helium, that's dissolved in 
your tissues, not nitrogen).

There are other advantages and disadvantages to helium/oxygen mixture:

The main advantage is that you are free from nitrogen narcosis (feels like 
being drunk, that can happen at deep dives)

BUT:

-Helium has higher heat conductivity than nitrogen. You can get mighty cold 
mighty quick.
-Helium/oxygen mixture is _expensive_
-You will sound like Donald Duck because of lower gas density. It can impair 
communication.

For VERY deep dives they use hydrogen/oxygen mixture. Hydrogen/oxygen 
mixture is explosive and can ignite at a smallest spark (static electricity, 
for example). So they have to make it inert, by putting very little oxygen 
in it (3% — compare to 20% oxygen in regular air). Therefore, this mixture 
is only breathable below 150-160 feet, when partial pressure of oxygen rises 
to breathable limit.

Advantages and disadvantages of hydrogen/oxygen mixture are pretty much the 
same as with helium/oxygen plus the fact it's only breathable at 160 feet 
and deeper.

Hope this helps.

Sincerely, Paul.

_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp