Extra-large round industrial duct
Large process/air system
Before you start
- Confirm the engineered erection procedure, section weight, center of gravity, lifting lugs, flange type, temporary bracing, structural supports, reinforcement, and weather conditions.
- Inspect shell, ring flanges, stiffeners, lifting points, and coatings.
- Establish an exclusion zone and rigging plan.
- Do not begin erection without approved structural and lift information.
Tools and materials
Extra-large industrial duct sections, bolted ring-flange hardware, gaskets, engineered rigging and spreader, temporary braces, structural supports, alignment pins, approved torque procedure, fall protection, and inspection equipment.
Lay it out
- Establish support coordinates and flange orientation.
- Mark lifting points and balance.
- Plan temporary and permanent bracing sequence.
Set and support it
- Install structural supports and temporary bracing.
- Rig from engineered lifting points.
- Control shell deformation during lift.
Make the connection
- 1
Lift the section under the approved erection plan.
- 2
Set it on structural supports.
- 3
Align ring flanges concentrically.
- 4
Install gasket and bolts loosely.
- 5
Bring the flange together evenly using the approved sequence.
- 6
Complete bolts per the approved procedure.
- 7
Install reinforcement and permanent bracing.
- 8
Remove temporary bracing only after load transfer is verified.
Check the install
- Flanges are concentric.
- All required bolts and reinforcement are installed.
- The shell is not buckled.
- Structural supports carry the load.
- Coating and stiffeners remain intact.
Common mistakes
- Lifting without a spreader or engineered points.
- Using bolts to pull misaligned flanges together.
- Removing temporary braces too early.
- Standing under or near an uncontrolled section.
Stop and ask
Stop without an engineered erection procedure, verified rigging points, structural support, temporary bracing, and weather-safe lift conditions.