What gas is used for installer pressure tests in medical gas lines?

The correct answer is the use of oil-free dry nitrogen for installer pressure tests in medical gas lines. This gas is preferred because of its inert properties, which means it does not react with other materials or create any potentially hazardous reactions during the testing process.

Using nitrogen for pressure testing ensures safety, as it is non-toxic and does not pose any risks associated with flammability or toxicity, which could occur with other gases. The oil-free requirement is particularly important in medical applications to avoid any contaminants that could affect the purity of the medical gases used in patient care.

Additionally, nitrogen's ability to maintain a stable pressure without causing any adverse effects on the materials of the gas line makes it ideal for testing. It can easily be purged from the system without leaving residues, unlike many other gases, which could introduce pollutants into the medical gas system.

These characteristics make oil-free dry nitrogen an essential choice for ensuring that medical gas lines are tested reliably and safely before they are put into operation.