HVAC turning vanes are sheet metal devices inside of mechanical ductwork used to smoothly direct air inside a duct where there is a change in direction, by reducing resistance and turbulence.
![](http://upload.wikimedia.org/wikipedia/commons/thumb/5/54/Turning_vanes_inside_of_large_durasteel_ductwork_06.png/170px-Turning_vanes_inside_of_large_durasteel_ductwork_06.png)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/5/52/Turning_vanes_inside_of_large_durasteel_ductwork_11.png/220px-Turning_vanes_inside_of_large_durasteel_ductwork_11.png)
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External links
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