Apprentice answer

Why can’t commercial kitchen grease duct just be hung level

3rd YearGrease Duct & Specialty ExhaustStop / Verify

Stop before the grease duct gets welded, wrapped, or closed in as a flat run. Verify the approved grease duct detail, slope direction, cleanout/drain requirements, and support elevation before continuing.

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Plain-English answer

Grease duct is not normal comfort-air duct. If a horizontal grease run is hung flat when the approved design requires slope or drainage, grease can pool in low spots and turn the install into a fire/inspection problem.

Do not guess the slope number from memory. Check the mechanical drawings, grease duct detail, hood/exhaust submittals, code/AHJ requirement, and foreman direction. Then adjust supports/elevations before the run is welded, wrapped, or made hard to access.

Field checklist

Confirm system is kitchen exhaust/grease duct, not normal exhaust.
Check the approved detail for slope direction, cleanout, drain/reservoir, access, weld/seal, and support requirements.
Measure start and end elevations before final welding/wrap/inspection.
Look for low spots where grease could collect.
Document any section already hung level before moving forward.

Ask Foreman

The grease duct run at [location] is being hung level/backpitched. I checked the detail and it looks like slope/drainage needs verification before we continue. Do you want me to hold and reset the hanger elevations per approved direction?

Verify before acting

Use this as training guidance. The foreman, approved drawings, project specs, manufacturer installation instructions, employer safety policy, and AHJ/code requirements always control the final answer.

Why can’t commercial kitchen grease duct just be hung level

Plain-English answer

Field checklist

Ask Foreman

Verify before acting

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