Riser Section Binds on a Sleeve or Floor Opening

Fast answer

Stop the movement and identify the exact contact point. Verify opening size, sleeve position, connector projection, reinforcement, insulation allowance, and section rotation before trying again.

What to check

1. Keep the section supported and stable.
2. Inspect all sides of the opening from a safe position.
3. Compare actual opening and duct dimensions with current drawings.
4. Check whether the section must pass in a specific rotation.

Do not

Do not ram, pry, hammer, or grind the opening while the section is suspended.

Ask the foreman

“The riser section is binding at the floor opening and is still supported. I checked the visible sides and the connector is contacting the sleeve. Do you want it lowered for measurement before we change anything?”

Why it matters

Forcing a bound section can damage the duct, sleeve, rated assembly, support equipment, or nearby workers.