Which of these is a requirement for each station inlet?

• A. A main vacuum line
• B. A primary valve
• C. A secondary demand valve
• D. A primary optional in-line

Answer: (B)

The essential idea is that each station inlet must include an isolation valve. This valve lets you shut off the gas to that specific inlet for maintenance, testing, purging, or in an emergency, without affecting the rest of the system. It also helps prevent backflow and cross-contamination between different rooms or areas, which is critical for patient safety and system integrity.

The other items don’t fit as a required feature of every station inlet. A main vacuum line belongs to the vacuum system, not the gas inlet itself. A secondary demand valve is a device used in specific equipment or contexts, not a universal requirement for the inlet. An in-line valve that’s optional wouldn’t guarantee isolation or control at the inlet, so it isn’t considered a mandatory component.