What is the definition of PSIA?

The correct definition of PSIA is that it refers to "Absolute measurement of gas." PSIA stands for "Pounds per Square Inch Absolute," which is a unit of pressure measuring the absolute pressure relative to a perfect vacuum. This measurement is crucial in various engineering and scientific applications, as it accounts for the total pressure exerted, including atmospheric pressure.

In contrast, gauge pressure typically measures the pressure relative to atmospheric pressure, which can lead to confusion if not properly understood. Understanding that PSIA includes atmospheric pressure is vital in contexts where precise calculations of pressure are necessary, such as in gas and fluid dynamics. Therefore, recognizing PSIA as an absolute measurement allows for a clear understanding of the true pressure exerted by a gas or liquid in a system, making it significant in stationary engineering and other fields.