Which item is commonly used as an inerting gas in processing facilities?

• A. Nitrogen
• B. Oxygen
• C. Argon
• D. Neon

Answer: (A)

Inerting gas is used to prevent ignition by reducing the amount of oxygen available in a process area. Nitrogen fits best because it’s abundant in air, inexpensive, and chemically inert under typical processing conditions. Introducing nitrogen lowers the oxygen fraction so that flammable vapors or dusts can no longer reach their ignition limits, reducing the risk of fires or explosions. It also neither reacts with process materials nor supports combustion, which makes it a reliable choice for general inerting.

Oxygen would worsen the hazard by increasing the oxidizer in the environment. Argon and neon are inert, but they are much more expensive and less practical for routine inerting in most facilities, so they're not the go-to choice.