welding oxygen

[phillip1]

This is probably going to sound dumb but, what is the difference between the o2 used to fill welding tanks and medical grade o2?

[FW]

This is probably going to sound dumb but, what is the difference between the o2 used to fill welding tanks and medical grade o2?

No difference at all, but how they clean the tanks is a different matter. Medical O2 (in the US anyway) requires emptying the tank under vacuum, then refilling with O2. For welding tanks, they just refill them as-is. The problem is sometimes acetylene gets in the tanks, if the previous user left toe O2 run out, before the acetylene.

Another option is Aviation O2. They are emptied, but not under vacuum, and are much less likely to have any strange gas in the tanks.

[Scott]

purity and contaminants.

Medical grade has been tested for CO and CO2 and only allows a certain ppm, welding (industrial) grade may or may not have depending on where you get it and what you ask for. Some states regulate Medical grade (like Va) so you can get industrial grade that has been tested to the same standards as medical.

there are others, but that is what i what i can recall off the top of my head.

Scott

[skip]

It's a matter of purity. Welding oxygen can be as low as 93% pure, depending on application. There's 99.9 (aviator), 99.98, 99.99, and 99.999..oh and 99.6 too. I also think the water content differs depending on grade.... Other's probably know more about the details and just how pure is necessary for breathing. We use the ultra high purity (UHP) which is the 99.99% and dry. However, here's a statement by a local supplier:

"There are four kinds of oxygen that are merchandised or sold to users; Aviation, Medical, Welding and Research. There is a ongoing controversy if there is any difference between the different types. Oxygen gas is produced from the boiling off of liquid oxygen. It would appear that the oxygen is therefor the same. Where we obtain oxygen, all the different types of oxygen are supplied from the same manifold system. Then someone says that medical oxygen has more moisture in it. That is partly true. The oxygen going to a hospital bed is plain oxygen that comes from liquid oxygen. At the bed location, there is a unit on the wall that adds moisture. At this moment we now have medical oxygen. If the oxygen is in a pressure vessel or in a manifold system (like inside a hospital) then it is regular oxygen. The cost of medical or welding oxygen is normally much less than the oxygen you get at an airport.

Also of interest, we have been told by the suppliers of welding oxygen, the purity level required for welding and cutting purposes is more critical than for breathing.

The bottom line about the different types of oxygen is in the insurance liability of the oxygen supplier. The gas is the same but the insurance liability is different."

skip

[Scott]

ahh, forgot liability. If you are a dive shop or charging people for fills, you want the gas that comes tested and with certifications of purity from the supplier, so if you get sued you can show that the gas was lab tested, if you are home brewing for personal use, then it really doesnt matter, just as long as you are ok with the gas you choose.

Cost is another thing, you will pay more for the 99.99% than you will for the 99.98%. Is the additional 0.01% worth 3-5 cents cu/ft?

[phillip1]

The hospitals here get o2 from the very same place that sells to the welders, a kind of "clean" and "organized" looking setup (for here that is) in Puerto Plata but still when I see the all the area hospital tanks (they have each hospital logo) to be filled right next to the welding tanks it makes me wonder.
i guess it is pretty much the same thing then.

[FW]

...i guess it is pretty much the same thing then...

Only if the tanks are clean!!

[ScubaAl]

I have been using welding O2 no issues. Here in MN you need a prescription for medical O2 as I don't have one just use the welding. The supplier also told me the welding was exactly the same as medical, coming for the same place minus the paper trail. Never have asked about aviator. One time while picking up O2 and Helium I made the mistake of saying I was using it to breath. The guy more or less freaked out, after he settled done I say to him "next time I guess I shouldn't say anything about breathing it" his comment was "that would be a good idea" Okay then

Al

[DA Aquamaster]

One time while picking up O2 and Helium I made the mistake of saying I was using it to breath. The guy more or less freaked out, after he settled done I say to him "next time I guess I shouldn't say anything about breathing it" his comment was "that would be a good idea" Okay then

Al

Right - that's the other side of the liability issue. They may be the same gasses but the paper trail is important if they know or reasonably suspect you are using He or O2 for breathng. If you don't tell them, then they can honestly claim they had no idea you, the dumb ass you died, were using the gas for breathing and they can assure all involved including your widow and her hearse chasing attorney that had they known, they would not have sold you welding gas.

[amphipod06]

Right - that's the other side of the liability issue. They may be the same gasses but the paper trail is important if they know or reasonably suspect you are using He or O2 for breathng. If you don't tell them, then they can honestly claim they had no idea you, the dumb ass you died, were using the gas for breathing and they can assure all involved including your widow and her hearse chasing attorney that had they known, they would not have sold you welding gas.

you could get a diving wife...

Dive safe,

Celia