Which device is a safety/pressure relief mechanism?

• A. Rupture disk
• B. Safety/Pressure relief Valve
• C. Fusible plug
• D. Relief vent

Answer: (B)

A safety/pressure relief mechanism is designed to automatically release contents when pressure reaches a preset limit, preventing overpressure and protecting the vessel. The safety/pressure relief valve fits this role because it senses pressure, opens at a designated set point to relieve fluid, and then reseals once pressure drops, providing ongoing protection.

Rupture disks also relieve pressure but do so only once and must be replaced after they burst. A fusible plug responds to high temperature, not pressure, making it a temperature-triggered safety device. A relief vent provides an outlet but does not automatically regulate pressure or reseat like a valve does.

So, the device that best serves as a safety/pressure relief mechanism is the valve, since it continuously and automatically manages pressure to maintain safe operating conditions.