Grease duct vertical riser
Vertical kitchen exhaust
The approved design, adopted code, qualified procedure, and exact manufacturer instructions control this installation.
Before you start
- Grease duct is a fire/life-safety system. Verify the approved design, adopted code, hood and fan requirements, listed enclosure or shaft details, and inspection hold points before fabrication or installation.
- Confirm the riser support and guide design, floor or shaft openings, thermal movement strategy, access locations, enclosure system, and rigging plan.
- Verify section weight, lifting points, joint type, and load-transfer sequence.
- Check that rated shaft or listed enclosure details remain compatible with supports, guides, and access doors.
- Establish a controlled shaft area and approved rigging method before lifting.
Tools and materials
Grease-duct riser sections, approved welded or listed riser joints, structural riser supports and guides, rigging equipment, plumb laser, access components, joint materials, inspection light, and shaft protection equipment.
Lay it out
- Establish a continuous plumb reference through all openings.
- Mark support, guide, access, and enclosure locations at each level.
- Verify that the riser will not bear on shaft walls, floor edges, or firestop components.
Set and support it
- Install and secure the lower load-bearing riser support before stacking the next section.
- Rig the upper section from approved lifting points and control rotation.
- Install guides that control lateral movement while allowing the movement required by the approved design.
Make the connection
- 1
Verify the lower section is plumb, correctly oriented, and carrying load at the designed support.
- 2
Lower or raise the next section into position without resting it on the joint.
- 3
Align the full perimeter and confirm access orientation.
- 4
Complete the continuous welded or exact listed modular joint.
- 5
Inspect the joint before the enclosure is closed.
- 6
Transfer the new section load to the approved riser support.
- 7
Install or verify guides, access components, and enclosure continuity before releasing rigging.
Check the install
- The riser is plumb and correctly oriented through every level.
- Dead load transfers through the designed supports, not joints or shaft walls.
- Guides and movement components match the approved design.
- Liquid-tight joints remain accessible for inspection.
- The shaft or listed enclosure remains continuous and compatible with access.
Common mistakes
- Using the transverse joint as the riser support.
- Releasing rigging before load transfer is confirmed.
- Allowing the riser to touch shaft construction or block firestop clearance.
- Installing guides so tightly that required movement cannot occur.
Stop and ask
Stop if the support load path, thermal movement, rigging plan, shaft opening, enclosure detail, or access arrangement is unclear or differs from the approved design.