Apprentice answer

Can I use regular duct sealant on the breakaway joints of a fire damper

2nd YearDampers, Fire/Smoke & Life SafetyStop / Verify

No. You cannot bridge across a fire damper breakaway joint (like an S&D connection) with heavy, thick layers of regular structural duct mastic that could cure hard and structurally lock the joint together. Use only light coats of approved non-setting sealants inside the joint slip track if required by the manufacturer's UL listing documents.

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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.
No. You cannot bridge across a fire damper breakaway joint (like an S&D connection) with heavy, thick layers of regular structural duct mastic that could cure hard and structurally...

Ask Foreman

Hey boss, I’m on dampers and need verification before I touch this: Can I use regular duct sealant on the breakaway joints of a fire damper? 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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