The power required by the fan for delivering air
at a given quantity increases rapidly according
to what change, if any, in duct size?
An increase only
2. A decrease only
3. An increase or a decrease
Rectangular fiber-glass ducts 24 inches or less
in diameter must be supported every how
What type of joint is used to absorb expansion
and contraction in a duct system?
When computing duct size, you should first
perform what calculation?
1. Air pressure
2. Air volume
3. Air velocity
4. Air movement
You can gain efficiency by installing what
type of elbow in a duct system?
1. Long, sweeping
2. Short, 90 degree
4. S curve
Short, 90-degree elbows can be used
effectively in which of the following locations
within an air duct system?
registers, diffusers, and grilles
7-31. When designing a duct system, you should
use what publication as a source of technical
1. Mechanical Engineering Manual
2. Duct Design and Fabrication
3. Construction Engineering Handbook
4. ASHRAE Handbook of Fundamentals
IN ANSWERING QUESTIONS 7-32 AND 7-33, REFER
TO FIGURE 7A.
7-32. The total pressure of the duct system is equal
to the pressure reading of what gauge(s)?
1. A only
2. B only
3. B plus A
4. B minus A
7-33. The velocity pressure of the duct system is
equal to the pressure reading of what
1. A plus B
2. A only
3. A minus B
4. B minus A
7-34. A newly installed duct system is balanced
in what manner?
1. By adjusting the speed of the fan
2. By drilling small holes in branch holes
3. By adjusting air outlets to the design rate
4. By installing dampers in the main duct