RE: [PSUBS-MAILIST] O2

[Alec Smyth <Asmyth@changepoint.com>]

My understanding is that welding O2 is what is used as a breathing gas
virtually always on commercial subs. In fact, there is a variety of medical
O2 which would be dangerous in a sub because it has CO2 added to it, to
trigger the breathing reflex. 

Alec

-----Original Message-----
From: Paul B [mailto:paul_victor@hotmail.com]
Sent: Tuesday, May 07, 2002 10:50 AM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] O2


As far as I know, oxygen is divided into 3 major groups:

1. Medical
2. Aviation
3. Welding

To get medical grade O2, you DO have to have a prescription. Now, in case 
with aviation grade as far as I know it's the same purity as medical. The 
difference is that you don't need a prescription to get it; and a tank, 
unlike in case with medical grade, does not have a unique serial number each

individual cylinder can be traced by, only the lot number. I think they're 
doing it in case of medical grade because life and death depend on it - they

need a way to find out where the stuff came from if something goes badly 
wrong.

Medical and aviation O2 cylinders are getting purged of all gases before 
they're filled with gas. Welding grade O2 cylinders are not. There's no 
telling what could be in it other than O2. For all you know, it could be CO 
or some other pretty nasty stuff.

However, welding O2 manufacturers say it's critical to have very pure O2 for

metal cutting purposes, so I guess that stuff should be more than fit to 
breathe.

I'd try my chances trying to get aviation grade first. And then, if I 
failed, I would talk directly to the manufacturer of welding grade O2 and 
ask him about chemical contents of his product.

Sincerely, Paul.

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