The Fan Law describes the dependence between the most important measurements for fans (Airflow, Static Pressure, Motor Power). It is important to know these Laws for the constructer and also for the customer to decide the right kind of fan, fan size and motor power for each special application. The basics of the Fan Law are shown in the following equations.   Q- Airflow SP- Static Pressure P- Motor Power N- Speed of Rotation 1- initial Measurement 2- finally Measurement Q1/Q2 = N1/N2 SP1/SP2 = (N1/N2)2 P1/P2 = (N1/N2)3 If you want to know more about the Fan Law please visits the sites which we provide you at our Link section.