Centrifugal fans are supplied from the factory with a certain orientation that will have been specified by the customer at the time of ordering. This orientation will depend on the application or installation, as well as the maintenance needs with the aim of making it as accessible and easy as possible.
Unless otherwise noted, the default assembling orientation for industrial range of centrifugal fans is LG270.
To understand the different possible orientations, in the following figures the viewer is located in front of the motor: