=+4-31.

For a 3000-ft' combination gym and exercise operation, it is desired to reduce the outdoor air intake rate to a minimum by filtering and air recirculation.

(a) Design a system using filters having an efficiency of 0.50 and a pressure loss of 0.14 in. wg at 350 fu/min face velocity. Pres-

sure loss should not exceed 0.20 in. wg. Outdoor air contaminants are negligible.

(b) Discuss how the choice of a filter would be influenced in this case should the cooling load require a larger supply air rate than the ventilation