Mirrored Offset: Verify Left-Hand and Right-Hand Before Installation
Compare the offset to the airflow direction, plan view, elevation, and the direction you will be looking before it leaves the ground. A fitting can have the right rise and run and still be mirrored.
I matched the rise and run, marked upstream, and checked the plan-view direction. This offset still moves opposite the coordinated route-do you want it remade or is the drawing view reversed?
Watch out
Do not call an offset correct only because the overall dimensions match
left-hand and right-hand orientation can still be wrong.
Check
Mark upstream and downstream on the fitting and adjoining duct.
Stand on the same viewing side used by the shop drawing or field sketch.
Confirm which way the offset moves in plan and which way it moves vertically.
Dry-check the connector ends and clearance before raising it.
Steps
Mark upstream and downstream on the fitting and adjoining duct.
Stand on the same viewing side used by the shop drawing or field sketch.
Confirm which way the offset moves in plan and which way it moves vertically.
Dry-check the connector ends and clearance before raising it.
Say this to your foreman
I matched the rise and run, marked upstream, and checked the plan-view direction. This offset still moves opposite the coordinated route-do you want it remade or is the drawing view reversed?