Deck 9: Air-Distribution Systems

Question 1

__________ are strips of metal that are formed into a flattened C shape. __________ are simply strips of metal formed into an S shape. Both are used in joining sections of galvanized sheet metal in a duct system.

Answer 1

Drives, Slips

Question 2

Mastic is a material used to:

A) support fiberboard duct sections
B) join sheet metal duct sections
C) seal fiberboard duct sections
D) seal metal duct sections

Answer 2

D

Question 3

Which type of duct material is commonly used for branch runs with a metal duct system?

A) galvanized metal
B) fiberglass-wrapped, spiral duct (flexible duct)
C) fiberglass, fiberboard sheeting
D) round sheet metal

Answer 3

D

Question 4

When connecting round metal ductwork, the male end connection should always face toward the air supply.

Question 5

A properly designed and installed air distribution system is a must if the space is to be evenly conditioned. Inadequate airflow to and from areas in the conditioned space can lead to __________, __________, __________, and __________. Excessively high humidity can result in __________, while low humidity can lead to __________.

Question 6

Which type of material is installed on the inside of the duct system?

A) foil-covered fiberglass insulation wrap
B) acoustical duct lining
C) either a or b
D) neither a nor b

Question 7

A drive connector should be installed on the short dimension of a rectangular galvanized metal duct section.

Question 8

A slip connector is installed on the short dimension of a rectangular galvanized metal duct system.

Question 9

The on-site installation time for a fiberboard system is __________ than for a prefabricated duct system, but the cost of the material is __________.

A) greater, less
B) less, greater

Question 10

If a duct system is installed correctly, it is not necessary to seal the joints because they will not leak.

Question 11

Which type of duct material has a high level of friction to air flow?

A) galvanized metal
B) fiberglass-wrapped, spiral duct (flexible duct)
C) fiberglass, fiberboard sheeting
D) round sheet metal

Question 12

At least ____ screws must be used to make connections for round metal ductwork.

A) 1
B) 2
C) 3
D) 4

Question 13

Which type of duct material is used in low-traffic areas and provides insulation to the duct system?

A) galvanized metal
B) fiberglass-wrapped, spiral duct (flexible duct)
C) fiberglass, fiberboard sheeting
D) round sheet metal

Question 14

What should be installed in a galvanized metal duct system to reduce sound transmission and vibration throughout the occupied space?

Question 15

Which type of duct system typically has the air handler located below the conditioned space and the ductwork running around the perimeter of the space?

A) plenum-type duct system
B) extended-type duct system
C) reducing-extended-plenum duct system
D) perimeter duct system

Question 16

Many green homes have HVAC ducts located within specially designed roof trusses, referred to as __________ trusses, or __________ floor trusses in two-story homes.

Question 17

Which type of duct system has the air handler located in a central position compared to the supply registers, and has supply registers normally located on the interior walls of the structure?

A) plenum-type duct system
B) reducing-extended-plenum duct system
C) perimeter duct system
D) extended-plenum duct system

Question 18

Which type of duct system is used on systems that have the air handler located at one end of the structure to be conditioned?

A) plenum-type duct system
B) extended-plenum duct system
C) reducing-extended-plenum duct system
D) perimeter duct system

Question 19

Which type of duct system is used primarily when the duct system and the air handler are not located on the same level?

A) plenum-type duct system
B) extended-plenum duct system
C) reducing-extended-plenum duct system
D) perimeter duct system

Question 20

Which type of duct system has the longest life expectancy?

A) galvanized metal
B) fiberglass-wrapped, spiral duct (flexible duct)
C) fiberglass, fiberboard sheeting
D) round sheet metal

Question 21

When are fiberboard duct systems are typically sealed? What material is used to secure the joints? Why is the possibility of air leakage low with these systems?

Question 22

Flexible duct is very popular for a number of reasons. List five of these reasons.

Question 23

List four practices that the technician should follow when installing flexible ducts.

Question 24

Whenever possible, the technician should minimize the use of flexible ducts, as __________.

Question 25

Quite often, galvanized sheet metal systems will leak at the __________, while round metal duct runs can leak __________.