From: Doug Jones <random@eau.net>
Subject: Re: highest pressure a person can take? and lowest?
Date: 15 Aug 1997
Newsgroups: sci.space.tech

earl@neosoft.com wrote:

> Wait a minuite!!
> H2 is EXPLOSIVE in range 4%-96% in O2
> At lesser (or greater) percentages it is flammable.
> As I recall there is no point on HO curve where there does not exist
> a strong potential for disaster. (Many a vivid picture of submarines
> wrecked by H2 concentration over 2% limit -- and submarine oxygen
> generators/aux mach rooms  wiped out buy a little O2 in H2- at 2000psi )

No, 98% H2/2% O2 is *not* flammable at any pressure- an arc can be
struck in the mixture and no flame will propagate, although extra
energy _is_ released in the arc by the reaction.

A ternary mixture of He/H2/O2 in 97/2/1 volume ratio was patented by
Rocketdyne many moons ago for use as a pressurant gas.  "Tridyne" would
be stored at high pressure and passed through a platinum catalyst to
produce warm He + H2O.  It promised better performance than straight
He because it kept the temperature higher despite the adiabatic cooling
in the storage bottle during discharge.

Platinum jewelry would be forbidden in a high-pressure chamber filled
with H2/O2, though, as well as any other catalysts for the reaction.

Hydrogen has been used in extreme pressure experiments on land because
it's lower density eases breathing effort.  Oddly enough, beyond 1500
foot depths, a small amount of N2 must be added to counteract the
tremors caused by some effects on the myelin sheaths of the nervous
system- it's a bit like cerebral palsy.  The breathing gas ends up
being quite a witch's brew.

--
Doug Jones  random@eau.net
I came this close to seeing Elvis: ->| |<- and then my shovel broke!