Flanges

About

Duct Flanges & Duct Collars for Inline Fan Installation Duct flanges and duct collars are the connection hardware that joins flexible ducting to inline fans, carbon filters, grow tent ports, and wall exhaust openings - providing a mechanical transition between the round sheet metal housing of fans and filter bodies and the flexible aluminum duct that runs between them. A properly fitted flange creates a secure, airtight connection that does not pull free under the suction pressure of the fan or the tension of the duct run. An improvised connection - flex duct slipped directly over a fan housing without a flange and held with tape alone - pulls free under load, creates air leaks, and reduces system performance. Flange Types Standard duct spigot flanges are the most common format - a short cylindrical stub that slips inside the flex duct ID, with a collar that bears against the duct end and provides a foil-tape sealing surface. These are the flanges pre-installed on most inline fans and carbon filters. When the built-in flanges on a fan or filter are damaged or when custom connections are needed (connecting to a grow tent port of a different diameter, connecting to rigid duct, or adding a branch takeoff), replacement and extension flanges provide the needed geometry. Duct collars for wall penetrations provide a finished, reinforced connection through a wall opening where flex duct passes from inside to outside the growing space. Browse our complete inline fans collection and flexible ducting collection . Sealing & Hose Clamps Foil tape around the flange-to-duct joint is the minimum sealing requirement for low-pressure grow room ventilation. For higher-pressure applications (multiple inline fans in series, long duct runs, air-cooled reflector systems) supplement foil tape with a worm-gear hose clamp over the flex duct at the flange insertion point for a mechanically secure, pull-out-resistant connection. Fast shipping. Related Guides & Resources Learning Ce