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Attaching small takeoff to large round duct

connorkatz | Posted in Mechanicals on

On my duct plan I have some 4,5 & 6 in branch airtight takeoffs that come off a 14in round trunk line that is metal.

My question is how to attach the smaller takeoffs to the large diameter trunk.

The saddle on the takeoffs is too tight of radius to attach to the trunk.

Whats the best way to do this, just use a flat takeoff?


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  1. Expert Member
    Akos | | #1

    Round trunk that big, you can go with flat takeoffs. Seal the sides with a heavy dose of mastic. You can also get saddle takeoffs (more for commercial work) that is that big.

    Why that big of a round duct? Usually something that needs that much flow is done in rectangular duct. Takes up less space, easier to bulkhead around and very easy to add top or side takeoffs.

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