What does a PSV or RV primarily protect against in a vessel?

A pressure safety valve (PSV) or relief valve (RV) is specifically designed to protect a vessel from overpressure scenarios. Overpressure can occur due to a variety of operational factors, such as thermal expansion of the contents, exothermic reactions, or equipment failures. When the pressure within a vessel exceeds a predefined limit, the PSV or RV opens to allow excess pressure to be released, thereby preventing potential damage to the vessel and safeguarding against catastrophic failures that could result from excessive internal pressure.

The function of these valves is critical in maintaining the integrity and safety of pressurized systems by ensuring that the pressure remains within safe operational limits. This is especially important in industrial processes where equipment failure or explosions can pose severe hazards to personnel and the surrounding environment.

While other options like temperature fluctuations, material corrosion, and flow obstruction are important considerations in the operation of vessels, they do not directly relate to the primary role of a PSV or RV, which is to manage and release pressure to prevent overpressure situations.