Overpressure protection encompasses the devices and systems designed to prevent equipment from exceeding its maximum allowable working pressure during abnormal conditions. Primary devices include pressure relief valves, rupture disks, and pilot-operated relief valves sized per API 520/521 to handle credible overpressure scenarios such as blocked outlets, fire exposure, or thermal expansion. Proper overpressure protection is a code requirement for pressure vessels and piping systems, forming a critical mechanical safeguard in process safety design.