What is Overpressure in Process?

Overpressure is excess pressure in a process equipment or pipe of its maximum allowable working pressure.

Overpressure can be caused by inflow exceeds outflow, which occurs if upstream flowrate control device fails or it there is blockage in the downstream or if there is condition of gas blow-by from upstream component.

Overpressure can also be caused by thermal expansion of fluids if heat is added while the inlet and outlet are closed.

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Overpressure is the pressure increase over the set pressure of the relieving device. It is expressed in pressure units or as a percentage of set pressure.

Overpressure is the same as accumulation only when the relieving device is set to open at the maximum allowable working pressure of the vessel.

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