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Mistake & recovery · #080

Not sizing a flex duct collar to match the rigid duct diameter, causing flow restriction

2nd YearDuct Systems

The flex collar must match the rigid duct diameter exactly. Going down even one size creates turbulence and static pressure loss. Check the schedule and u…

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Safer field move

The flex collar must match the rigid duct diameter exactly. Going down even one size creates turbulence and static pressure loss. Check the schedule and use the correct collar size — field substitutions are not acceptable.

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Can you verify this before I keep going? I’m looking at: Not sizing a flex duct collar to match the rigid duct diameter, causing flow restriction. What’s the approved correction for this job?

Do not

Do not hide, force, cover, or “make it work” if this affects safety, access, airflow, rated assemblies, supports, equipment, or inspection. Stop and verify the approved correction.

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