1. The air volume moving through a duct is 100 cfm. The duct has a diameter of 6”. Find:
 a.  velocity in fmp
b. pressure drop
 

2. In the figure below
 A = 80 ft; B = 100 ft; C = 50 ft; D = 80 ft

For architectural and structural reasons, the ductwork must be held to a 15 inch height throughout. The runouts are each 40 ft. The fan outlet is 1500 fpm.  Pressure loss through the last outlet is 0.07 in WG. Pressure loss through the return, outside air duct and filter bank is 1 in. WG.

a.  size the ducts for: A, B, C, D, E, F, G, H
b. Find the horsepower of the fan motor.
 

3. A system has a duct run handling 300 cfm of air inside a room. The total effective length is 170 ft. Let’s assume that the fan is capable of moving the correct air flow in the supply duct with a friction loss of 0.36 in. WG. Cooling coil loss = 0.24. Supply register loss = 0.03.
 Find the duct diameter.