Absolute pressure must always be?

Absolute pressure is defined as the total pressure within a system, measured relative to a perfect vacuum. This means it takes into account all atmospheric pressure plus any additional pressure exerted by gases or vapors within the system.

In the context of engineering applications, it is essential to measure pressures in absolute terms because many calculations—such as those involving gases, fluid dynamics, or thermodynamic processes—rely on the accurate understanding of the absolute pressure level. For instance, when calculating vapor pressures, buoyancy, or when utilizing equations of state, the use of absolute pressure ensures that the effects of atmospheric pressure do not skew the results or lead to inaccuracies.

By always expressing pressure as an absolute value, engineers can maintain consistency and reliability in their designs, safety evaluations, and operational practices. This standardization is crucial in avoiding misinterpretations that could arise from fluctuating atmospheric conditions, which can affect gauge pressure readings but would not impact absolute pressure measurements. Thus, stating that absolute pressure must always be considered is fundamentally correct given its importance across various applications in power engineering and related fields.