12
Duct Preparation
3. Add (1) and (2) to determine the total equivalent straight length of the
complete duct system: 25’ + 15’ + 4’ = 44’ total equivalent straight duct length.
4. For the system with 3 ¼” x 10” duct, the maximum allowable total equivalent
straight length of duct is 60 feet. Thus, this proposed installation is proper.
After determining that your proposed duct work meets the maximum duct length
requirement, proceed with the location planning.
