Verify diameter, piece mark, direction, and centerline
Seat the joint fully
Check support, clearance, and seal path
Ask foreman
In Spiral, Round & Oval Duct Install, I’m looking at: What do I do when not checking round-to-rect transition orientation? What should I verify before I cut, drill, seal, cover, move, or install?
Do not
Do not force, crush, or screw round duct into a bad fit.