Range hood duct clearance to joists & drywall

[muilebon]

The hood duct needs to run through kitchen ceiling and vent out in a wall (not roof).
My joists are 2 x 8 with the ceiling drywall dating back to the 1950s.
What is the max duct diameter I can install in my joists space?
Is there any clearance (air gap) consideration between the pipe and joists and
drywall?

 

[Jadnashua]

My limited experience with installation of a range hood is that there isn't any clearance required. The installation instructions of the range hood you select should point out if there are any. The air shouldn't be hot enough to be a problem. There usually is a set of grease traps prior to the ductwork that needs to be kept clean to both not block the air flow and prevent a fire from getting into the duct. There could be some vibrations that could be transmitted into the structure that might want some clearances, but that's not a safety or code issue.