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Operating Pressure

Operating pressure of equipment occurs when the plant or process is operating at steady state conditions.  Operating pressures may or may not be constant depending on the process and variations in operating parameters.  Variations in operating pressures may be expressed as the maximum operating pressure and the minimum operating pressure.  The maximum and minimum operating pressure is the pressure for deviations within normal operations such as process upsets, start-up and shut down.

working pressure 1It's important to maintain operating pressure within specified limits to ensure the safe and efficient operation of equipment and processes.  Deviations from the recommended operating pressure can lead to performance issues, safety hazards, or damage to equipment.

Common Applications / Limitations

Applications  -
Piping system design and material selection (ASME B31.3)
Pressure vessel design margins (ASME Section VIII)
Pump/compressor sizing and seal selection (API 610)
Relief valve set-pressure determination
Limitations  -
A single steady-state operating pressure value does not capture transient events (surge, water hammer, thermal expansion), these must be evaluated separately.
Operating pressure can vary across a piping run due to elevation and friction losses; a single quoted value may oversimplify actual conditions.
Using operating pressure (instead of design pressure/MAWP) for component selection is a common and unsafe design error.

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