Fan rotation, discharge orientation, and startup access need to be checked before duct is connected and sealed. A wrong fan orientation is not something duct should hide.
Do not force duct to equipment, block service access, or hang duct weight from equipment.
Check
Check the fan submittal or schedule for discharge orientation, rotation/access side, and service clearance requirements.
Compare the unit on site to the submittal. Inline, centrifugal, and roof fans can have different discharge arrangements that look similar at first glance.
Confirm startup access: motor, belt, controls, nameplate, access panels, and test points should be reachable without dismantling duct.
If the discharge orientation does not match the submittal, stop before connecting duct. The fan may need to be corrected or reoriented before the duct can connect properly.
Photograph the fan nameplate and connection side if there is any doubt.
Steps
Check the fan submittal or schedule for discharge orientation, rotation/access side, and service clearance requirements.
Compare the unit on site to the submittal. Inline, centrifugal, and roof fans can have different discharge arrangements that look similar at first glance.
Confirm startup access: motor, belt, controls, nameplate, access panels, and test points should be reachable without dismantling duct.
If the discharge orientation does not match the submittal, stop before connecting duct. The fan may need to be corrected or reoriented before the duct can connect properly.
Photograph the fan nameplate and connection side if there is any doubt.
Say this to your foreman
The fan at [location/tag] appears to have [describe discharge/access orientation], but the submittal shows [describe]. They [match / do not match / are unclear]. Do you want me to confirm with the equipment contractor before I connect duct?