Grease duct versus regular exhaust duct not recognized
Treat grease/special exhaust as red-zone work: not recognizing grease duct versus regular exhaust duct.
High-risk starter answer - treat grease duct, hood exhaust, kitchen exhaust, lab exhaust, and special exhaust as red-zone work. If the duct serves a hood/kitchen/process area or has welded/special construction, do not treat it like regular exhaust until it is identified.
Ask any time grease/special exhaust involves access, weld, wrap, slope, clearance, penetration, contaminant, or support questions.
Watch out
Do not assume normal galvanized duct rules apply.
Check
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.
Trace what equipment it serves and ask the foreman to confirm the system type.
Steps
Confirm the system is grease, kitchen exhaust, industrial exhaust, dust, or chemical/fume exhaust.
Check approved detail for material, access, cleanouts, joints, wrap, slope, and support.
Identify hot-work or fire-watch requirements.
Focus on the actual issue: not recognizing grease duct versus regular exhaust duct.
Photograph or mark the condition if someone else needs to approve it.
Say this to your foreman
In Grease Duct, Kitchen Exhaust & Industrial Exhaust, I'm looking at: Grease duct versus regular exhaust duct not recognized. What should I verify before I cut, drill, seal, cover, move, or install?