Originally Posted by
rickair7777
I think private pilots learn about this.
Medical O2 has water vapor (normal ambient humidity) so as not to dry out the patient's lungs and throat.
Aviation O2 is dry, so that it doesn't form ice in the delivery system when the regulator drops the pressure, and subsequently the temperature.
Medical O2 used in the prehospital environment is as dry as a bone. Moisture is only added for long term use in medical facilities.
Should have remembered that fact was in my private curriculum. It was a couple of decades ago. However, as I said earlier, I stand corrected on that point.