Which of the following listed valves would require "blow down" to insure proper operation and prevent damage due to repeated and rapid opening and closing?

Correct Answer: Option C — Safety valve

Safety valves require a specific blowdown pressure differential to ensure they snap shut cleanly. Without this design feature, the valve would hover near the set pressure, causing rapid cycling, seat damage, and wire-drawing of the valve disc and seat, which compromises the pressure boundary integrity of the boiler or system.