What safety device is essential in preventing boiler overpressure?

A pressure relief valve is critical in preventing boiler overpressure because it acts as a safety mechanism designed to release excess pressure from the system. When the internal pressure exceeds a predetermined limit, the pressure relief valve opens, allowing steam or water to escape, which helps to lower the pressure back down to safe operating levels. This function is essential for maintaining safety in boiler operations, as overpressure can lead to catastrophic failures or explosions.

While safety shutoff valves, pressure gauges, and feedwater regulators each play important roles in boiler operation and safety, they do not directly serve the same purpose as a pressure relief valve. A safety shutoff valve is used to stop the flow of fuel or steam in case of an emergency, a pressure gauge monitors the pressure but does not mitigate it, and a feedwater regulator controls the water level and supply in the boiler but does not address the pressure issue directly. Therefore, the pressure relief valve is the key device specifically engineered to prevent dangerous overpressure situations in boilers.