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Flanged Ductwork

Flanged Duct by US Duct

Flanged Ductwork

US Duct provides duct with flanges (also called angle rings or angle flanges) in black iron, galvanized, or stainless steel (SS) and with or without holes.

The duct to which these flanges are attached is available in sizes 3″ and up, and also in black iron, galvanized or SS.

Construction methods range from laser welded pipe and mechanically lock elbows in lighter gauges to fully welded product in heavy gauge (even up to 1/4″)—all depending upon the application.

Types of Flanged Duct

Vanstone Flange

This refers to a technique whereby a flange is used to mate 90-degree lips turned onto the pipe or duct component. In this method the flange is placed onto the pipe, the lip turned back and the flange left loose. Typically, the lip is ½” tall (or wide depending on your perspective) when the flanges are pulled together, the VanStoned lips of the pieces that are being connected, are pressed together to make a secure metal to metal connection. Because the flanges are loose on all pieces, alignment of the center-line of the components is easily accomplished. Standard Vanstone pipe lengths are a nominal 59”.

Welded Flange

Welded flange refers to flanges that are welded to the duct. The faces of the flanges are the mating surface, as opposed to the Vanstone where the duct lips are mating. Full welded duct flanges have a continuous weld. Intermittently welded duct flanges mean that there is a weld at intervals around the duct. Standard welded flange pipe lengths are a nominal 60”.


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