What is a pressure relief valve designed to do in a system?

A pressure relief valve is specifically designed to protect a system from excessive pressure. Its primary function is to open automatically when the pressure within the system exceeds a predetermined level. This opening allows for a controlled release of the excess pressure, thereby preventing potential damage to equipment or hazards to safety.

By automatically relieving pressure, the valve helps maintain the integrity of the system, ensuring that it operates within safe limits. This functionality is critical in various applications, including boilers, pipelines, and chemical processing systems, where overpressure can lead to catastrophic failures.

The other options do not align with the primary function of a pressure relief valve. Regulating temperature, controlling steam flow, or measuring pressure are distinctly different operations associated with other components in a system, such as temperature control valves, flow control valves, or pressure gauges. Each of these has a specific role that does not encompass the primary purpose of a pressure relief valve.