In the fan flow equation Q=CA(2∆P/ρ)^n, what does ∆P represent?

In the fan flow equation ( Q = CA(2∆P/ρ)^n ), the symbol ( ∆P ) stands for the pressure differential. This pressure differential is crucial because it represents the difference in air pressure across the fan or through the building envelope that is being tested. The flow of air, and subsequently the airtightness of the building, is influenced by this pressure differential, as it drives the movement of air through any leaks or openings present.

Understanding pressure differential is essential for evaluating how effectively a building can resist the flow of air, thereby determining its overall airtightness. Recognizing the role of ( ∆P ) in this equation helps in calculating the airflow based on the resistance encountered, delivering insights into energy efficiency and the potential for air leaks within a structure.