Term: Jump Duct

A flexible, short, U-shaped duct (typically 10-inch diameter) that connects a room to a common space as a pressure balancing mechanism. Jump ducts serve the same function as transfer grilles. Used when return ducts are not located in every room.

Source: Info-604: Transfer Ducts and Grilles; RR-0006: Discussion of the Use of Transfer Grilles to Facilitate Return Air Flow in Central Return Systems