What is the absolute pressure measured in psi?

The correct answer is measured in pounds per square inch absolute, abbreviated as psia. Absolute pressure quantifies pressure relative to a perfect vacuum, meaning it includes the atmospheric pressure in its measurement. This distinction is crucial in many industrial applications, particularly in refrigeration systems, where accurate pressure measurements can significantly impact system performance, efficiency, and safety.

In contrast, psig (pounds per square inch gauge) measures pressure relative to atmospheric pressure, which means it does not account for atmospheric pressure when providing readings. This can lead to misunderstandings in situations where accurate absolute pressure is necessary. Other options such as psib and psid aren't standard terms used in pressure measurement; psib could imply some specific context not commonly applied, while psid typically refers to pressure differential, which is again not relevant to absolute pressure measurements. Understanding the correct terminology and application is essential for effective operation and maintenance of industrial refrigeration systems.