True/False
Indicate whether the sentence or statement is true
or false.
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1.
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The
amount of air flow (CFM) that is delivered by a blower depends on the resistance (pressure) that the
blower has to work against?
True or False
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2.
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To
meet the objective of good duct design, the duct system must be designed so that the air flow
resistance , in terms of static pressure drop, matches the external static pressure that is developed
by the blower when the blower delivers the desired CFM?
True or
False
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Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
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3.
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A
friction rate is equal to the pressure loss that occurs between two point in a duct system that are
separated by a specific distance.Friction charts and duct slide rules use 100’ for the reference
distance. What would you assume the pressure drop would be in a typical residential duct
system. a. | 0.5 “
W.C. | c. | 5”
W.C. | b. | .1”
W.C. | d. | .8”
W.C | | | | |
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4.
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The
formula for finding FR when the system pressure drop is know is? a. | FR=PD
x100
100 | c. | PD=.5
x100
100 | b. | PD=FR
x100
100 | d. | FR=.8x100
100 | | | | |
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5.
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How
do you determine available static pressure when doing your design? a. | Exam all device
pressure losses and subtract from manufacturers external static pressure at your desired
CFM | c. | Measure in
field | b. | Blower static pressure
measurement | d. | Calculated
CFM | | | | |
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6.
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Using
your ductulator with a friction rate of 0.05 for galvanized duct @ 480 CFM what would the size of
your round duct be for these conditions?
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7.
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Using
your ductulator with a friction rate of 0.05 for galvanized duct @ 480 CFM what would the friction
rate be for these conditions? a. | 600 fpm | c. | 800 fpm | b. | 1200
fpm | d. | 400
fpm | | | | |
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8.
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If
you have a round duct diameter of 8” what would be the round duct area in square
inches?
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9.
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If
you want to deliver in a rectangular duct which is 8 x ? an amount of air equal to 200 CFM at a 0.05
friction rate, what would the 8 x ? be?
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10.
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To
deliver 150 CFM of air to a space with a friction rate of 0.05 what size wire helical flexible duct
would you need?
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11.
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In a
residence what would be the problem with a main duct run delivering 1,000 CFM @0.05 friction rate
with a size being 50 x 8? a. | Velocity to low and duct costly to fabricate, too
large | c. | Velocity to
high | b. | Nothing | d. | FPM to
high | | | | |
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12.
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If my
duct system pressure drop is equal to 0.05 W.C and my duct is to delivery 200 CFM at a length of 200
feet, what would be my required design friction rate?
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