What is an essential condition for a LOX converter to require purging?

A LOX (liquid oxygen) converter requires purging primarily when it has been emptied. This process is essential to remove any residual oxygen that could potentially pose a fire hazard or create an explosive atmosphere if allowed to remain. After the converter is emptied, the purging process ensures that all oxygen is expelled from the system, making it safe for maintenance or storage.

Purging is not dependent on the duration of use, age, or end-of-life status of the converter, but rather on the specific operational condition of having been emptied. Ensuring that no oxygen remains in the system is vital for safety, particularly in aviation environments where flammable materials and conditions exist.