Can standard spiral duct be used for commercial kitchen grease exhaust?

Field answer

Kitchen grease or liquid-bearing exhaust needs approved liquid-tight construction. Lockseam spiral can leak through the seam and create sanitation, fire, and inspection problems.

Stop the work, identify the system type, and verify the required listed/welded material, cleanouts, slope, wrap/clearance, and inspection detail before continuing.

What to check first

• Confirm whether the line is true grease/kitchen exhaust or another exhaust type.
• Look for leakage at lockseam, joints, and fittings.
• Check drawings/spec/material schedule.
• Document any contaminated dripping or food-area exposure.
• Hold for foreman/detailer/AHJ direction before operating or covering.

Why it matters

Wrong grease exhaust construction can create fire risk, health issues, failed inspection, and major rework.

Ask foreman

Text this wording

Related Field Rescue route

Open routeBack to Q&A

Final direction belongs to the foreman, approved drawings/specs, manufacturer instructions, pressure/material schedule, employer policy, and AHJ/code requirements.