What is the purpose of a vent in a piping system?

• A. To drain condensate
• B. To seal joints
• C. To relieve trapped air and allow flow/pressure equalization
• D. To indicate flow direction

Answer: (C)

Air trapped in a piping system can block flow and cause pressure fluctuations. A vent gives that air a path to escape as the line fills or pressure changes, and then allows air to re-enter to balance pressure downstream. This keeps fluid moving smoothly, reduces issues like air pockets and pressure surges, and helps proper system operation. That’s why the vent’s purpose is to relieve trapped air and enable flow and pressure equalization. Draining condensate, sealing joints, or indicating flow direction are accomplished by other components or features, not the vent.