Turning Vane is used to “turn” the air flow in 90 degree Square Elbows on Rectangular Duct jobs. These Vanes are usually cut on a chopsaw from 10 ft lengths then Mounted on Rail that is itself screwed onto each of the Elbow’s interior cheeks.
The efficiency of Turning Vanes in Square Elbows is understanding that the Width of a duct is greater in the turn than the duct size itself. This means that by Stacking turning vanes onto Rail that extends from the throat to the corner of the heel of the Elbow provides turning surface for the airflow to move.
Installing 2” turning vanes on Ductmate PROrail and then into a Square Elbow.
Turning vane and the accompanying rail are used in rectangular ductwork when a ninety degree bend is needed.
This assembly is used in a square throat elbow in lieu of a radius elbow which can be more difficult and time consuming to build. The vanes are used to redirect airflow for increased efficiency and less turbulence or static pressure. It is important to keep air movement flowing in a ductwork system so that velocity and air volume are ensured at the terminal devices. It is also important to reduce the amount of static pressure so that air handlers are not overworked.
There are several types of vanes that may be used. SMACNA allows the use of single thickness vanes in either 2” or 4” width up to 36” in length. The 2” or small double wall vane can be used up to a length of 48”. The 4” or large double wall vane can be used up to a length of 72”
The minimum gauge of the 2” vane is to be 26 and the 4” is to be 24. The distance between the 2” vane is to be 2 1/8” while the 4” is to be 3 ¼”.
Radius elbows take up more space than Square Back Elbows with Turning Vanes as shown in duct design
2” Hollow Vane and 2” PROrail shown installed to turn air in Square Backed Elbows. Often used when there are space constraints as they take up less space than Radius Elbows.
The determination of using a Square Elbow with turning vanes ( like the 2” hollow vane mounted on 2” Ductmate PROrail shown here) or a Radius Elbow ( curved heel and throat) is specified by engineer but usually with latitude of changing to the Sheet Metal contractor’s preference. Aero Dyne Turning Vane (Aerodynamic) are directional Turning Vanes which means that it’s best practice to mark the airflow direction on the elbow so that it’s installed correctly. Conklin Item codes DHEP-TV and ADHEP-R This video was shot at BCH Mechanical in Largo, FL
