Do not support wide flat-oval duct like a small round branch if it is deforming.
Check
Inspect bottom panel sag and side radius distortion.
Check if the support bears on one narrow line.
Verify flat-oval support detail and spacing.
Temporarily support before modifying hangers.
Confirm airflow path is not deformed after correction.
Steps
Inspect bottom panel sag and side radius distortion.
Check if the support bears on one narrow line.
Verify flat-oval support detail and spacing.
Temporarily support before modifying hangers.
Confirm airflow path is not deformed after correction.
Say this to your foreman
The flat-oval duct at [location] is sagging across the trapeze bar. I checked the support contact and shape. Do you want a shaped saddle/wider cradle or internal support detail?