Treat grease/special exhaust as red-zone work: slope direction wrong on horizontal grease duct.
High-risk starter answer - treat grease duct, hood exhaust, kitchen exhaust, lab exhaust, and special exhaust as red-zone work. Grease or residue collecting in the wrong place is a red flag.
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.
Flag low spots, wrong slope, trap points, or drainage questions for the foreman before closing the run.
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: slope direction wrong on horizontal grease 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: Slope direction wrong on horizontal grease duct. What should I verify before I cut, drill, seal, cover, move, or install?