Vacuum purge involves evacuating the vessel, then introducing inert gas.

• A. Sometimes
• B. False
• C. Never
• D. True

Answer: (D)

Vacuum purge is a two-step method used to reduce fire and explosion risk by first removing air and vapors and then flushing the space with an inert gas. The vessel is evacuated to create a low-pressure environment, pulling out air and any flammable vapors. After the evacuation, inert gas is introduced to displace the remaining air, establishing an inert atmosphere and further lowering the oxygen and vapor concentrations. Because this sequence—evacuate, then introduce inert gas—is the defining part of a vacuum purge, the statement is true. It’s not something you’d do only sometimes or never; the process is specifically about evacuating first and then purging with inert gas.