A sweep purge creates a controlled, inert-gas atmosphere in the vessel.

• A. True
• B. False
• C. Not necessarily
• D. Depends on gas

Answer: (A)

A sweep purge is used to push air out of a vessel and replace it with an inert gas, typically nitrogen, to create an atmosphere that does not support combustion. This controlled inert atmosphere reduces oxygen levels and lowers the risk of ignition from flammable vapors during entry or work inside the vessel. Because the purpose and outcome of a sweep purge are to establish that inert environment, the statement is true. The idea isn’t about using any gas or leaving the atmosphere unsure—it’s about intentionally displacing air with an inert gas to achieve a non‑reactive environment.