What is the disadvantage of the local exhaust ventilation system?
a. It is not efficient.
b. It weighs less.
Installation of ductwork causes an inflexible work area.
d. The cost is initially high but it is more efficient to operate.
The basic laws governing the complete motion of a fluid, such as air, are widely
known and relatively simple.
What is the air-flow rate if the velocity was measured at 210, 320, 195, and 305
ft/min for a duct that is 12" by 36"?
a. 257.5 cmf.
b. 386.25 cfm.
d. 1030 cfm.
What consideration is needed for circular ducts when determining the rate of air-
flow? Use the:
a. Radius of a circle.
b. Area of a circle.
Area of a square.
d. Diameter of a circle.