Do you know the types of elbows used in rectangular duct?
- Sign as seen hanging at Sig Cox (founded 1926), Sheet Metal Contractor in Augusta, GA
The determination of the types of elbows used in a duct job depend on a variety of factors, some of which are the engineer’s preference, the contractor’s influence and the space allowances.
- Radius elbows take up more space than Square Back Elbows with Turning Vanes as shown in duct design
- In the case of the NOLA new airport project, the engineer had a preference for radius fittings and there was abundant space for which to work chose radius and elbow fittings on this large duct. There is however, one square backed elbow visible; bonus points if you can identify.
- 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.
- 2” Vane and Rail Installed in Square Back Elbow
- Turning vanes are installed to redirect air flow in square elbow fittings
- Radius elbow with Square Throat
- Radius Elbows with Radius Throat (reinforced with Tie Rods)
- Radius Elbow with tight throat radius
- Elbows made with Buttonlock instead of Pittsburgh will usually appear to be in more pristine condition because they haven’t had to withstand the tinner’s hammer required with the Pittsburgh Lock
