There are several misconceptions associated with Aviators Breathing Oxygen (ABO):
Misconception #1: ABO is Different. This is probably the most common misconception about ABO and includes the incorrect notions that it’s drier than medical oxygen or welder’s oxygen, it’s cleaner and it’s made by ATP-qualified elves in the Black Forest. No matter what you’ve been told, the truth is that all commercial grades of oxygen produced today, including ABO, are exactly the same. There are ultra-pure grades used for science and research purposes but this variety is outside the normal distribution chain. Welding oxygen is the same. Medical oxygen is the same. Industrial oxygen is the same. All such oxygen is produced by the same distillation process, in the same plant and with the same equipment to the same specification. It’s shipped in liquid form to major distribution centers. There are no separate tank cars or trucks for ABO. It all comes out the same port; it just goes into different (often identical) cylinders with different labels. The only difference is the paperwork, the distribution system—and the cost. The purity requirements for industrial and welding oxygen today are actually more stringent than the old mil-spec for ABO. Decades ago, there were differences because the methods of production differed; today there are none. If you don't believe me, go to a gas production plant and watch. If that doesn’t convince you, you probably still believe in Santa Claus and the Tooth Fairy.
Misconception #2: FARs Require ABO. Wrong. There’s no FAR
that requires you to use ABO. The only place the FAA says anything on the subject is in some old Advisory Circulars. AC
43.13-1A (Acceptable Methods, Techniques, and Practices – Aircraft Inspection and Repair) lists a maximum moisture content specification for ABO. All oxygen currently produced exceeds this specification by a mile. It’s absolutely dry by virtue of how it’s produced (distillation) and distributed (as a liquid). Those who claim medical oxygen is different because it has more moisture so it doesn’t dry out patients’ pulmonary systems haven’t been to a hospital in the past few decades. They bubble the oxygen through water to moisturize it because it’s so dry. So, there’s no water to freeze up your aircraft’s oxygen delivery system, portable or otherwise, as some mistakenly believe. AC
65-9A (Airframe And Powerplant Mechanics General Handbook) says “Only oxygen marked ‘Aviator’s Breathing Oxygen’ which meets Federal Specification BB
-0-925a Grade A or equivalent
may be used in aircraft breathing oxygen systems” (emphasis added). For portable, non-TSO’d oxygen systems, even this recommendation (remember, the “A” in AC
stands for advisory) isn’t applicable. However, my point is to again look at the reality of Misconception #1; there’s no difference between oxygen, so by default, it’s equivalent. And, in any case, all oxygen made today is far superior to that antiquated specification.
Misconception #3: No ChapStick. This is another Old Wives Tail. The theory is that you can’t use ChapStick or lipstick when using an oxygen mask because the oil in them will cause it to spontaneously ignite in the presence of pure oxygen. No doubt that’s why so many emergency medical patients have ended up with burned lips, the EMTs didn’t wipe off the lipstick—not. While you do have to be very careful about introducing oil into the oxygen refill and delivery system because of the dangers of combining high-pressure oxygen and oil and the potential for rapid and significant temperature rises that could cause spontaneous combustion, by the time it gets to your lips, it isn’t an issue. The guy filling and handling oxygen bottles needs to worry about this, you don’t.
Misconception #4: Only FBOs Can Fill Cylinders. Nope. There’s no federal regulation that prevents you from refilling your own oxygen cylinder.
Hope this helps.