Industrial exhaust material not matched to contaminant
Treat grease/special exhaust as red-zone work: industrial exhaust material not matched to contaminant.
High-risk starter answer - treat grease duct, hood exhaust, kitchen exhaust, lab exhaust, and special exhaust as red-zone work. Special exhaust may carry hazards that are not obvious from the duct shape.
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.
Confirm system type, contents, material, labeling, and who is authorized before modifying anything.
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: industrial exhaust material not matched to contaminant.
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: Industrial exhaust material not matched to contaminant. What should I verify before I cut, drill, seal, cover, move, or install?