Gilldiver
Contributor
The military did some extreme tests with scuba tanks. They put water in pressurized cylinders and put them in wet, hot conditions. From those extreme conditions we can draw some conclusions about how to store scuba cylinders:
1. A clyinder expands everytime it is filled and contracts when emptied. Repeated expansion and contraction fatigues the metal and eventually it will fail. (This is why we do hydro testing every five years, to detect cylinders that no longer tolerate repeated expansion/retraction.) So, it is best to store cylinders nearly empty to reduce metal fatigue.
2. Small amounts of mositure inside of the cylinder cause corrosion. If the tank is stored on its side, the corrosion is spread across the thinner sidewall. If the tank is stored upright, the corrosion is focused on the thicker base. Thus cylinders should be stored upright.
3. Oxidation of the metal cylinder is directly proportional to oxygen content, or the partial pressure of oxygen. Therefore cylinders should be stored almost empty to minimize the partial pressure of oxygen and corrosion.
4. In steel cylinders, oxidation of the steel consumes oxygen in the breathing gas and has been shown to dramatically reduce the oxygen content of the gas in certain situations. Therefore, steel clyinders should be stored nearly empty so that must be filled with fresh gas before use. Alternatively, the gas in a steel cylinder must be tested for oxygen content after long-term storage.
I will try to remember all of this the next time I am looking at the steel O2 storage tanks in my cascade. The ones at full pressure and with the original Hydro dates going back to 1909.
What you have stated has no backup data, it is just regurgatated BS.