What happens when the pressure exceeds the set limit on a pressure relief valve?

When the pressure in a system exceeds the set limit on a pressure relief valve, the valve opens to relieve excess pressure. This is a crucial safety mechanism designed to prevent potential damage or failure of equipment due to overpressure conditions. By opening, the valve allows fluid to escape, reducing the pressure within the system to safe levels.

Pressure relief valves are essential components in various applications, including boilers, pressurized tanks, and piping systems. Their primary function is to safeguard against the hazards of excessive pressure buildup, which could lead to catastrophic failures or explosions. Therefore, the opening of the valve is a necessary response to maintain operational safety and integrity in the system.

The other options do not accurately describe the behavior of a pressure relief valve in response to excessive pressure.