What is a pressure relief valve and why is it necessary?

A pressure relief valve (PRV) or pressure safety valve (PSV) is a device that automatically releases fluid when system pressure exceeds a set value. Purpose: protect equipment from overpressure that could cause rupture, protect personnel from equipment failure, meet regulatory requirements (ASME, API), and prevent environmental releases from equipment failure. Key specifications: set pressure (relief opening point), overpressure (allowable above set pressure, typically 10%), and relieving capacity (sized for worst-case scenario). Relief scenarios include: fire, blocked outlet, cooling failure, tube rupture, and runaway reaction. Every pressurized system must have adequate overpressure protection.