Re: [APML]: H2

["Patrick W. Greenlee" <patrickg@nosc.mil>]

>Hazards aside is it legal to keep pure H2 in a tank without some sort
>of licence?

Can't address, legal,not always logical.

>What are the precautions for handling the stuff?

Pure hydrogen is not a danger in and of itself.  Lay the cylinder down or
secure it well and in any case protect the neck of the bottle and valve
assembly from impact danger.  It could get messy if you break the cylinder
open (true for most any highly compressed gas flamable or otherwise).  The
danger is when yoiu mix hydrogen with air (oxidizer).  There is a range of
fuel air ratios that will explode violently.  Recall the Hindenberg?
Static sparks too small to be felt or seen coud ignite an explosion.  An
advantage of hydrogen is that it doesn't collect in low places like many
other fuel gasses/vapors.  Good ventilation is a key to safe handling.
Mentally invert the space (room, shop, etc.) where you wold use it.  Now
mentally flood the space with water.  Would any collect?  If yes, then so
would hydrogen and that is dangerous.  Another safety precaution is
grounding (earthing on the other side of the pond).  Ground everthing to a
central point and connect that to a good ground (cold water pipes work well
if they are all metal).  You might want to consider wearing a grounding
strap yourself, like the ones we are supposed to wear when changing static
sensitive computer chips.

The dangerous part of hypering with pure hydrogen would be when it isn't
pure, i.e. when mixed with tha air in the hypering chamber.  During the
process of flushing out the air in the chamber by introducing hydrogen you
will for a while have a bomb waiting for a source of ignition.  Past that
point there is virtually no danger until the chamber is opened and a
mixture of air and hydrogen is produced again.

It would seem that it you had a bottle of nitrogen or other inert gas that
had no deleterious effect on film that you could first flood/flush the
chamber with that, expelling the air (oxygen) and then introduce the
hydrogen with impunity, there being no way to get an explosive situation
with hydrogen sans an oxidizer.  Similarly at the end of the hypering cycle
you would use the inert "flushing" gas to expell the hydrogen from the
hypering chamber with no chance of making a bomb.

I hope I didn't make this sound too complicated it, isn't.

 I'm sure there are OSHA and or industry guides to working with explosive
gasses.  You might want to look into that.


>Where can I get some?

Most gasses that are components of the atmosphere are available from "air
reduction" businesses.  Places that "make" oxygen, nitrogen, etc.  Welding
supply houses might be a first place to call followed by scientific supply
houses.

How do hypering times with pure H2 differ with hypering in
>forming gas? Are the advantages of hypering with pure H2 vs. forming gas
>distinctly remarkable?

Can't say, this is out of my comfort zone but there are probably others who
will.

Patrick