A building exhaust fan for a large commercial building weighs 180 pounds and operates at a speed of 600 rpm. Due to manufacturing tolerances, it may have a rotating imbalance. It is desired to limit force transmissibility to 2.5 as the fan passes through resonance during startup and wind-down. In addition, an Isolation of 90% is required at the operating speed of the fan. The fan's framework will be supported from the floor at 4 corners. Design, select, and specify vibration isolators at the four corners. It is acceptable to assume the center of gravity is symmetrical with respect to all four corners, enabling you to treat this as a single DOF system without pitch or yaw.