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View Full Version : Medical Ox, Industrial Ox, What's The Difference?


DougC
11-21-2001, 11:08 AM
- - - While buying welding gas I saw a notice that the gasses sold were "intended for industrial use only". Now I already know that they put a small percentage of something in industrial nitrous oxide to make you gag if you inhale it, but what's the difference between medical and industrial oxygen? You can't mix anything reactive into 200-bar oxygen, so anything added would have to be nearly (or totally) inert: high-pressure oxygen equipment has to be kept basically sterile, literally clean enough to eat off of, no matter what circumstances it is used under. The problem with the inert chemical theory is that if the added chemical was inert, it wouldn't matter if you breathed it.
Are inert gasses toxic or unpleasant to breathe?
-Keep in mind here, anything added would have to be a rather small percentage of the total..... - DougC

Shagnasty
11-21-2001, 11:16 AM
There may not be anything added to it at all. The warning may just be a standard disclaimer so that people don't use industrial oxygen for weird things. This reminds me of laboratory ethanol that I used to work with. It had a stern warning on the side of the one gallon bottle that it was not for human consumption. However, it was laboratory grade which meant that it had to be absolutely pure with nothing added to it to denature it. I never did it, but if someone took laboratory ethanol and mixed it with some plain old laboratory water, they would have ended up with some of the cheapest, finest VODKA that can be had. Of course, that kind of thing is strongly discouraged by science supply companies so they put the warning on the side of the bottle to scare the timid away from trying it.

Inky-
11-21-2001, 11:22 AM
Industrial oxagen has a little sulpher dioxide (smells like rotten eggs) added just so it can be detected if there is a leak or open valve.

Ethilrist
11-21-2001, 11:28 AM
May not be related, but industrial CO2 has something in it (lubricant?) while food-grade (what you'd use to force-carbonate or dispense soda or beer) doesn't.

Bob Scene
11-21-2001, 01:30 PM
According to this site, (http://hbd.org/hbd/archive/2488.html) the only difference is that oxygen that's sold for medical purposes has to be tested more thoroughly, and that's what makes it cost more. Here's what it says:

Bottom line: CO2 is CO2. The only differences in the gas industry that I know of are Medical Grade CO2 and Ultra High Purity CO2 for the semiconductor industry. These two grades of gas are simply tested for purity, but typically come from the same source that the beverage/welding/industrial grade comes from. This is usually the case with Argon, Nitrogen, and Oxygen as well. Industrial grade oxygen and Medical grade oxygen cylinders both get filled from the same bulk liquid tank. The grading is simply done as a test on the gas in the cylinder to ensure its purity.

That sounds convincing to me, but if you really need to know and Homebrew Digest isn't authoritative enough for you, I'm sure you could call Air Liquide or Matheson or whoever and ask them.

By the way, some oxygen may have an odorant added, but I found one company's online MSDS's for their gases, and they had the same MSDS for industrial and medical grade oxygen that specifically said that the product was odorless.

ReillyDog
11-21-2001, 01:45 PM
Inky - I think you might be thinking of natural gas or propane. Both of these gases have that familiar smell added to them to help detect leaks.

NotMrKnowItAll
11-21-2001, 01:49 PM
Originally posted by Shagnasty
There may not be anything added to it at all. The warning may just be a standard disclaimer so that people don't use industrial oxygen for weird things. This reminds me of laboratory ethanol that I used to work with. It had a stern warning on the side of the one gallon bottle that it was not for human consumption. However, it was laboratory grade which meant that it had to be absolutely pure with nothing added to it to denature it. I never did it, but if someone took laboratory ethanol and mixed it with some plain old laboratory water, they would have ended up with some of the cheapest, finest VODKA that can be had. Of course, that kind of thing is strongly discouraged by science supply companies so they put the warning on the side of the bottle to scare the timid away from trying it.

My Dad, an entomologist, had tons of that stuff about. He preserved aquatic insects in it(terrestrial ones got cyanide!). We (he, a grad student, and I) went on an extended collecting trip (A.K.A. Campout), and found ourselves in vast tracts of dry counties in West Texas. He mixed up some Ethanol-Sunrises which were to die for.

MonkeyMensch
11-21-2001, 02:15 PM
I can vouch for what Bob Scene has pointed out. I used to work for a medical and industrial gas supplier and can tell you that we had a single liquid oxygen tank out back feeding both the industrial and medical pumping supply lines. Since any cylinder was always evacuated with a strong vacuum pump before filling, the amount of contaminants in either type of bottle would not only be minimal, but the same as well.

My guess is that some nice government regulators, in protecting ourselves from being stupid, had these types of labels made mandatory. Once the cylinders have been out in use, say in welding, there is a chance of contamination from back pressure, or some bad connection. The label tells Joe Public that he's being a dork when he connects up his used welding cylinder to Grandpa's oxygen mask.

That's my opinion. Of course I could be wrong.

DougC
11-21-2001, 06:56 PM
...Once the cylinders have been out in use, say in welding, there is a chance of contamination from back pressure, or some bad connection.... - M&M
- - - I don't know, but I don't think welders and doctors use the same sizes of tanks: welding tanks are shorter and fatter, where medical tanks tend to be taller and thinner.
~
- I was using it today anyway, so I took a moment and cracked the valve and smelled it, and couldn't smell anything.... --_____-wa-wa-wA - WOOOOOOOOO HOOOooooOOooO Truly!...Baroness!...Come sit next to daddy! Oh...you...Chitty Chitty BanG bANg, chITty cHiTtty baNng BBang weE LovE yoO.... - DougC

Hail Ants
11-21-2001, 09:26 PM
Medical grade CO2
I'm no doctor, what medical use does carbon dioxide have?

waterj2
11-21-2001, 10:29 PM
You use it in medical grade Coca-Cola.
;)