Abstract: A branch take-off airflow device for use in an air distribution system that includes coaxial input and output ducts and one or more branch ducts having a status pressure regain section and a take-off section that has a central passageway and one or more take-off passageways. Each of the take-off passageways is generally rectangular in transverse cross-section and defined by inner and outer walls with the latter being a continuation of a wall defining the output opening of the regain section. The inner wall has a thick, rounded leading edge where the take-off passageway commences. In one preferred version, there is an elongate air flow defining member located centrally in the main passageway of both sections and extending in the axial direction. This member has a generally round, transverse cross-section with a maximum diameter equal to or less than the diameter of the hub of an adjacent axial fan.