WorksheetsAir distribution systems
Total questions: 20
Worksheet time: 11mins
How do you determine the R-value of duct insulation?
It is based on heating
It is based on cooling
It is determined by the volume of airflow
Which ever needs the most, heating or cooling
Which of the following is the type of fan or blower wheel with a blade design that is self cleaning and a good choice for air containing dust and grease?
Radial blower wheel
Backward inclined blower wheel
forward curved blower wheel
Condensor fan
What is the purpose of a cross break on sheet metal duct?
To make the duct more ridgid
To make the duct square
To mark cut lines
To mark the center of the duct
Which of the following is a correct statement about fiberglass duct board?
It can be used to insulate metal duct
It has the lowest friction loss
It is the strongest material to make ductwork
It is self cleaning
Which of these math expressions are used to calculate velocity pressure in an air duct system?
Velocity pressure = total pressure - static pressure
Total pressure + static pressure = velocity pressure
Static pressure - velocity pressure = total pressure
Total CFM - static pressure = total pressure
Regarding fiberglass duct board, What is the purpose of the foil face?
To create a vapor retarder
To reflect light
To allow heat transfer
To create a cleanable surface
What is the maximum length of an extended plenum?
24'
12'
8'
36'
Which are correct statements about fire dampers? Select all that apply
A fusible link will melt at 165 degrees
It is spring loaded
They are used to control airflow
They are primarily used in residential
Which type of system is installed in a concrete slab to spread the heat out evenly?
Perimeter loop system
Extended plenum system
Transitioning duct system
Spider plenum
How is the air that forms in layers described?
Stratify
Venturi
Radiant
Mixed
How is the area of free space on a grill or register calculated?
Ak factor
Duct calculator
By multiplying the dimensions
With a manometer
Which of the following actions can improve the performance of ceiling diffusers in the heat mode?
Install return grills down low
Install return grills up high
Dampen the airflow
Not adding a return to the space
Which of the following characteristics best describes a backward inclined centrifigal blower wheel? Select all that apply
They are more efficient than forward curved wheels
They operate at higher speeds than forward curved wheels
They are primarily used in residential applications
They are more effective in higher resistance systems
Where is the highest pressure in an air distribution system found?
At the blower outlet
At the blower inlet
At the register
At the plenum
Which instrument is calibrated to read the lowest pressure ranges with the highest sensitivity?
Inclined Manometer
Sling Psychrometer
U tube Manometer
Digital manometer
What is being measured in the opening on the side of a pitot tube when connected to a manometer?
static pressure
CFM
humidity
temperature
At what length of a branch duct do they need to be started at the main trunk as metal?
6'
10'
15'
12'
What is a function of a damper in an air duct?
To raise the temperature
To direct and control air flow
To lower the temperature
To add humidity
How do you distinguish a fan from a blower?
Fans move airflow parallel to the shaft
Blowers are bigger
Blowers move airflow parallel to the shaft
Fans move air perpendicular to the shaft
Which instrument provides the information to determine relative humidity?
Sling psychrometer
Manometer
Magnahelic
Flow hood
