Why can't commercial kitchen grease duct just be hung level?

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.

['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.']

Stop if

• 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.

Check

• Grease pooling is a life-safety and inspection issue. Fixing slope after welding, fire wrap, or ceiling close can be expensive and ugly.

Steps

• 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.

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