How is a contaminated oxygen system typically purged?

A contaminated oxygen system is typically purged with nitrogen due to nitrogen's inert nature and its ability to displace contaminants without reacting with them. When purging an oxygen system, it is important to eliminate any residual contaminants that could pose a safety hazard when the system is re-pressurized with oxygen. Nitrogen is considered a safe choice because it does not support combustion, which is vital in maintaining safety in an oxygen-rich environment.

Using water would not be effective in purging an oxygen system, as water can introduce additional contaminants and may damage sensitive components. Oxygen itself cannot be used for purging contaminated systems, as it would not eliminate the contaminants but instead could exacerbate the risks associated with them. Argon, while inert as well, is typically more expensive and less accessible than nitrogen, which makes nitrogen the standard choice for safely purging such systems.