Re: [PSUBS-MAILIST] Hydrogen Peroxide

["Sean T. Stevenson" <ststev@uniserve.com>]

The oxygen does indeed come from the same source.  The only difference
between the welding stuff and the medical grade is the filling process
- welding tanks have one vacuum pulled on them, while the medical tanks
have a vacuum, are flushed with oxygen, have another vacuum pulled, and
then are filled.  That and the medical tanks are analyzed and certified
as to their hydrocarbon, CO, moisture content, etc.  One industry
insider told me that the information would be identical to the welding
gas if you analyzed it.  The scenario you describe seems unlikely,
unless it occurred a long time ago, or with a shady supplier.

The gas analysis and tracking of the medical grade is just a liability
thing, but at a cost, which they kindly pass on to you.  Don't ask,
don't tell seems to be the policy with the gas suppliers - if you say
you are using it for diving, they insist on the USP (medical) gas
grades for liability reasons.  I know a few people who have been diving
for years on welding O2 and balloon helium without incident.  Also, gas
prices seem to fluctuate greatly between suppliers, and even between
outlets of the same supplier!  A bit of haggling can't hurt - as with
everything else in life, you don't get what you deserve, you get what
you negotiate.

-Sean


On Sat, 24 Jun 2000 13:42:55 EDT, Subscuba@aol.com wrote:

>Vance,
>
>Divers in the local area used to use a home cooked (partial pressure) method 
>of mixing gases to get "Hyperoxy," now called Nitrox. The source of the gas 
>was from the local welding shop as you have suggested.
>
>One diver used the oxygen and died from it. Seems like CO (carbon monoxide) 
>was allowed as a contaminate in the welding gas. Since the gas was being used 
>not as a welding gas, his widow didn't have much luck with a lawsuit. Of 
>course, even with a successful lawsuit, it wouldn't have helped the diver.
>
>Medical grade oxygen has much tighter quality control and might be safer to 
>use. I know the source of the oxygen is the same.
>
>I toured the Ben Franklin when it was in West Palm. I understand there was a 
>report written after the voyage (The Gulf Stream Mission), do you know where 
>the report might be found? I saw the LOX storage tanks used on board and they 
>weren't too big about 3 feet high and 2 feet dia. I don't know how many they 
>had on board.
>
>Thanks,
>
>Ken Martindale
>