An example of this information appears in Table 1. This information should be based on tests performed using the fans as it will normally operate, including use of guards, shutters, discharge cones and other accessories. Beware of using manufacturers' data if it is not backed by an independent laboratory. AMCA has been the industry standard for many years. Fans that have been tested by AMCA will carry a decal similar to the one in Figure 3.
Efficiencies generally are better for larger fans than small ones.
Example fan data for a 24-inch fan with shutter, guard and discharge cone. Static Pressure Speed Airflow Efficiency in. Typically, mechanical ventilation systems include multiple fans. Various ventilation rates are needed due to the ever-changing outdoor temperature. A minimum ventilation rate is established to maintain a degree of air quality in the building during the winter.