overpressure

Overpressure is the pressure within a system or environment that exceeds the surrounding ambient pressure. In technical use, it denotes a transient rise in pressure caused by a sudden event, such as a shock wave from an explosion, a fast release of gas from a pressurized vessel, or a water hammer in a piping system. It is usually measured as the difference between the instantaneous pressure and ambient atmospheric pressure, i.e., the gauge overpressure, and is expressed in units such as kilopascals or pounds per square inch.

In blast physics, overpressure is the peak pressure above ambient produced by a shock front. The magnitude and duration of the overpressure determine potential damage to people, structures, and equipment.

In geology and petroleum engineering, formation overpressure describes pore fluid pressure that exceeds hydrostatic pressure, often due to diagenetic processes, tectonic loading, or hydrocarbon generation. Detecting overpressure is important for drilling safety and for evaluating fracture gradients.

In industrial practice, overpressure events include gas-release transients, compressed-air system surges, and safety relief events. Systems are designed with relief devices, venting, and structural measures to limit peak pressures.

Measurement and monitoring rely on pressure sensors with fast response, calibrated to translate transient peaks into standardized overpressure values. Standards and thresholds vary by application and jurisdiction.