Triangular Duct Dimensions Equivalence to Round or Rect Ducts
Triangular Duct Dimensions Equivalence to Round or Rect Ducts
(OP)
I am trying to size a traingular shaped return air duct and haven't found a table equating it's dimensions to those of a rectangular or round duct for air flow equivalence and inches of water. Does anyone have any guidelines?
Thanks!
P.S. I am doing this to shove the return air into the side of an attic where the rafters meet the attic floor.
Thanks!
P.S. I am doing this to shove the return air into the side of an attic where the rafters meet the attic floor.





RE: Triangular Duct Dimensions Equivalence to Round or Rect Ducts
dh = 4 * (cross sectional area / wetted perimeter)
If, on the other hand, you want to find an equivalent circular duct having equal FLOW RATE and PRESSURE DROP, the formula is a little more complicated but it will be something like 10% greater diameter than that given by the above formula.
Regards,
Brian