When the desired operating point falls within the fan characteristic region of higher system pressure and lower volumetric flow, single-entry front-bend centrifugal fans should be considered. If the application requirement is for high flow in a confined space envelope, a dual inlet forward bend centrifugal fan should be considered. When the desired operating point falls in an area where the system pressure is higher and the volumetric flow rate is lower on the fan characteristics, a single inlet forward bend centrifugal fan should be considered. If the application requirement is for high flow in a confined space envelope, a dual inlet forward bend centrifugal fan should be considered.