Portico Developer Guide
Card Security Code (CVV2, CVC2, CID)
1. Introduction External Static Pressure (ESP) is the cornerstone of HVAC airside design. It represents the total resistance that the fan must overcome to move air through the external components of the system—namely, the supply and return ductwork, grilles, diffusers, filters, coils, and sound attenuators. ESP does not include the internal pressure drop of the fan or air handling unit (AHU) cabinet itself.
$$\Delta P_f = f \cdot \fracLD_h \cdot \frac\rho v^22$$ esp calculation for duct
$$ESP = (P_supply + P_return) + P_accessories$$ the supply and return ductwork