Duct near equipment needs its own support so the equipment collar is not carrying duct weight. If the duct sags into the unit connection or pulls on a flex connector, add support before making the final connection.
Do not let duct weight, brace tension, or hanger error pull on equipment.
Check
Identify the nearest duct hanger to the equipment connection and compare it to the approved detail, project spec, or shop standard for that unit connection.
Look at whether the duct weight is being carried by the equipment collar. If the duct visibly sags toward the equipment, the connection is under load.
Check the flex connector if one is used. It should sit relaxed, not stretched, compressed, or acting like a hanger.
Add or request a hanger close to the equipment before final connection if the approved detail requires it or if the collar is carrying load.
Do not load the equipment connection and plan to fix support later. The joint stress starts as soon as duct weight is hanging on the collar.
Steps
Identify the nearest duct hanger to the equipment connection and compare it to the approved detail, project spec, or shop standard for that unit connection.
Look at whether the duct weight is being carried by the equipment collar. If the duct visibly sags toward the equipment, the connection is under load.
Check the flex connector if one is used. It should sit relaxed, not stretched, compressed, or acting like a hanger.
Add or request a hanger close to the equipment before final connection if the approved detail requires it or if the collar is carrying load.
Do not load the equipment connection and plan to fix support later. The joint stress starts as soon as duct weight is hanging on the collar.
Say this to your foreman
I do not have a duct hanger close to the [RTU/AHU/VAV/fan] connection at [location]. The nearest hanger is about [distance] away and the collar looks like it may be carrying weight. Do you want me to add support before I make the final connection?