What does PSID stand for?

PSID stands for Pounds per Square Inch Differential, which is a unit of measurement used to express pressure differences between two points within a fluid system. The "differential" aspect indicates that it measures the difference in pressure rather than absolute pressure at a single point. This terminology is crucial in various engineering applications, especially in fluid dynamics, HVAC systems, and process engineering, where knowing the pressure drop across a system helps in design and troubleshooting.

Understanding PSID is essential for engineers because pressure differentials affect flow rates, system efficiency, and can indicate potential problems within the system. The other options introduce variations in terms of units or terminology that are not commonly used or recognized in the same context, which clarifies why they do not accurately represent PSID.