Confirm whether this is grease duct, kitchen exhaust, lab exhaust, industrial exhaust, or normal exhaust.
Check the approved drawings/spec/submittal.
Look for cleanout/access, clearance, enclosure/wrap, weld/seal, slope/drainage, and inspection requirements.
Verify whether any penetration or modification is allowed and who is qualified/responsible before touching it.
Ask foreman
In Grease Duct, Kitchen Exhaust & Industrial Exhaust, I’m looking at: What do I do when not checking roof penetration/curb detail? What should I verify before I cut, drill, seal, cover, move, or install?
Do not
Do not assume normal galvanized duct rules apply. Do not drill, screw, notch, tap, or cut into grease/special exhaust without approval.
