Definition - What does Operating Pressure mean?
An operating pressure is the amount of internal force applied to the walls of some type of pressure vessel during normal conditions. When a system is at its operating pressure, it is generally running at optimum performance. Failure to maintain operating pressure could result in failure of the entire pressurized system.
Corrosionpedia explains Operating Pressure
Operating pressure is typically defined as a range for most pressurized systems. Depending on the how critical the application is, the pressure range could be very small. Generally speaking, it is detrimental to the system if its pressure is above or below the operating pressure range. If the pressure of a system is below its operating pressure range, it will most likely not operate at all because it lacks the energy to perform its intended function. If the pressure of a system is above its operating pressure range it can end in system failure.
Safety equipment is often installed for when a system falls out of its operating pressure range. Examples include pressure sensors that alert personnel when the pressure has shifted and pressure relief valves that open when the pressure becomes too great so that complete system failure does not occur. These valves will typically be set just above the maximum allowable operating pressure.