shows an air supply

Figure 5 shows an air supply duct arrangement to distribute the 2137 cubic foot per minute air flow to the rooms of the building in proportion to the heat gain in each room.  The flow quantities are shown at each outlet diffuser. Since the pressure available is .2 inches of water and the pressure loss at each outlet diffuser is assumed .04 inches, there is .16 inches of water pressure for the ducts.  The ducts will be sized to make the total pressure loss equal in each run.  Lengths of each duct segment are shown in feet.  Additional length must be added to each run to account for losses in elbows and the entrance at the air handler.  From Reference 2 the entrance is found to be equal to 10 feet of straight duct and the elbows equal to 35 feet. Duct sizes will be found for round and rectangular shapes.  Equivalent round and rectangular ducts can be found in Reference 1 or online at the website