Maximum pressure allowed in the system.

This is the maximum system pressure to which the disc may be exposed without causing premature metal fatigue to the rupture disc. Maximum operating pressures are typically between 50% and 100% of the rated burst pressure of the disc, depending on the type of disc. (Also known as Maximum Operating Pressure to Burst Pressure Ratio)

The maximum internal pressure expected during the operation of a pipeline, which cannot normally exceed the maximum allowable operating pressure.