3.5 The American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) specify that the minimum fresh air ventilation requirement for a residential building is 0.35 air changes per hour. This means that in 1 hour, 35% of the air contained in a residence should be replaced by fresh, outside air. Consider a residence that has 2000 ft2 of living area with 8-ft ceilings.

The fresh air ventilation requirements of this residence are to be met by a single fan. Determine the following:

a. Volumetric flow capacity (in cfm) of the fresh air ventilation fan

b. Circular duct diameter (in in.) required if the fresh ventilation air velocity is not to exceed 780 ft/min