Apprentice answer

How do I layout a welded grease duct slope so grease drains toward the hood

3rd YearGrease Duct & Specialty ExhaustStop / Verify

Horizontal grease duct runs under 75 feet long must slope a minimum of 4 1 inch per linear foot (2% slope) back toward the commercial hood or an approved grease reservoir collection trap. If the horizontal run exceeds 75 feet, the slope must increase to at least 1 inch per linear foot.

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Plain-English answer

Field checklist

Stop and verify the approved detail, manufacturer instructions, foreman direction, and project specs before touching it.
Horizontal grease duct runs under 75 feet long must slope a minimum of 4 1 inch per linear foot (2% slope) back toward the commercial hood or an approved grease reservoir collection...

Ask Foreman

Hey boss, I’m on specialty duct and need verification before I touch this: How do I layout a welded grease duct slope so grease drains toward the hood? Do you want me to stop here and check the approved detail, submittal, or inspector/manufacturer requirement first?

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.

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