Size, Pressure & Special Routing · Size, Pressure & Special Routing
Negative-pressure exhaust duct
Exhaust/suction
ConnectionSealed/gasketed/welded
SupportSupports preventing deformation
Before you start
- Confirm design negative pressure, duct construction, reinforcement, liner, joint seal, flexible connectors, and support spacing.
- Inspect panels for weakness, loose liner, dents, and inward deflection.
- Verify connectors and access doors are rated for suction conditions.
- Plan supports that prevent panel deformation.
Tools and materials
Negative-pressure exhaust duct, approved sealed, gasketed, or welded joints, reinforcement, stable flexible connectors, supports, sealant, inspection light, and test equipment.
Lay it out
- Mark reinforcement and support locations.
- Keep loose liner and internal components out of the suction path.
- Coordinate access doors and connectors.
Set and support it
- Install supports that preserve shape.
- Support fittings and connectors independently.
- Keep panels square during connection.
Make the connection
- 1
Verify construction against the negative-pressure requirement.
- 2
Align and mechanically connect the joint.
- 3
Install all reinforcement.
- 4
Seal the joint continuously.
- 5
Secure liner edges and internal components.
- 6
Inspect flexible connectors for inward stability.
- 7
Test or operate and watch for panel suck-in.
Check the install
- No panel sucks inward.
- Joints remain airtight.
- Liner stays secure.
- Connectors remain stable.
- Supports prevent deformation.
Common mistakes
- Using positive-pressure assumptions on exhaust duct.
- Leaving loose liner edges.
- Installing a floppy connector that collapses.
- Skipping reinforcement.
Stop and ask
Stop if duct walls deflect, liner is loose, a connector collapses, or construction does not match the negative-pressure duty.