keep rectangular duct from tipping or collapsing during staging receiving, staging & shop-to-field flow rectangular duct tipping collapse stack staging wide duct oil can flange damage laydown stage rectangular duct on stable bearing points and in a stack arrangement that will not tip, rack, crush lower sections, or damage reinforcement. this wide transition is leaning on its flange and the stack shifts when we pull a piece. where do you want it supported before we continue unloading?