Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Heating Service Exam > Air Flow & Duct Work > Flashcards

Air Flow & Duct Work Flashcards

1
Q

The conditions in the atmosphere refer to ______?

A

Weather

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The density of air is:

A

How much air weighs per cubic foot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

The specific volume of air is:

A

How much volume 1 pound of air occupies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The relative humidity of air is:

A

The percentage of moisture air is holding as opposed to the amount it could hold if it were saturated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

As air is heated it:

A

Expands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The air pressure in a sealed balloon is:

A

Static pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

A blower connected to a length of duct creates:

A

static pressure, which is then converted to velocity pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Velocity pressure is determined by:

A

Subtracting static pressure from total pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

An inclined manometer is basically a:

A

U-tube manometer tilted at a steep angle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

An inclined manometer is basically a:

A

U-tube manometer tilted at a steep angle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The static pressure of a duct is 1.76”, and the total pressure is 2”. What is the velocity pressure?

(Velocity Pressure = Total pressure - Static Pressure)

A

.24”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The static pressure of a duct is 1.76”, and the total pressure is 2”. What is the velocity pressure?

(Velocity Pressure = Total pressure - Static Pressure)

A

.24”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

A pitot tube can directly measure:

A

Total and static pressures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How many holes must be made in a round duct in order to take a series of traverse readings?

A

Two

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How many holes must be made in a round duct in order to take a series of traverse readings?

A

Two

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

A thermo-anemometer measures:

A

fpm directly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Dehumidification occurs when an air conditioning coil:

A

operates at or below the dew point of the air moving across it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Dehumidification occurs when an air conditioning coil:

A

operates at or below the dew point of the air moving across it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

When testing a duct system to determine its leakage rate, why is a special test stand necessary?

A

It contains a calibrated orifice and matching flow chart for that orifice.

It is manufactured to accepted testing standards.

Test results can be traced to the specific test stand used for the test if there are concerns about accuracy.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

When the dry bulb temperature increases, the relativity humidity of air:

A

Decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

When the dry bulb temperature increases, the wet bulb temperature:

A

Increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

When the dry bulb temperature increases, the dew point temperature:

A

Remains the same

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

When the dry bulb temperature increases, the specific humidity:

A

Remains the same

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

When the dry bulb temperature increases, the specific volume of the air:

A

Increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

When the dry bulb temperature increases, the density of air:

A

Decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

There are _________ grains of water vapor per pound of water.

A

7,000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

There are _________ pounds per cubic foot of air.

A

.075

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

The cfm per ton rate for normal comfort cooling is approximately:

A

400 cfm/ton

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Cooling air raises its:

A

Relative humidity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Air with a dry bulb temperature of 60 degrees and a wet bulb temperature of 60 degrees has a relative humidity of:

A

100%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Air with a dry bulb temperature of 60 degrees and a wet bulb temperature of 60 degrees has a dew point temperature of:

A

60 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Decreasing the cfm over an evaporator will _______ the moisture removal from the air.

A

increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

A rotating velometer measures:

A

feet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Return air grilles are not to be installed in:

A

Bathrooms or kitchens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

The proper amount of air in cfm for each room is determined by:

A

A detailed room-by-room heat load calculation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

On residential duct installations the accepted method of attaching duct sections to each other is:

A

Using the slip and drive method

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Which of the following is not an acceptable location for a thermostat?

A

5” off the floor on an outside wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is the difference between accuracy and precision when applied to instruments?

A

Accuracy is a measure of how close the measurement is to being correct. Precision is the measure of how small a value the instrument can detect.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

The range of an instrument is the:

A

difference between the lowest and highest readings the instrument can measure

40
Q

difference between the lowest and highest readings the instrument can measure

A

4,000 cfm

41
Q

A 32” by 32” square duct is to be changed to a height of 28” so it will fit around an obstruction in a boiler room. How wide must the duct be in order to maintain the same area? Round the number off to the nearest whole number of inches.

A

37”

42
Q

(T/F) The greater the velocity, the more resistance there is to a change in direction.

A

T

43
Q

(T/F) If the duct area decreases, the velocity increases.

A

T

44
Q

(T/F) When a fitting creates turbulence, the turbulence continues for several feet down the duct.

A

T

45
Q

A 24” by 8” rectangular duct has an aspect ratio of:

A

3:1

46
Q

The most efficient method of air balancing a duct system is the:

A

proportional method

47
Q

Which of the following types of turning vanes produce the least dynamic system loss?

A

Single wall vanes

48
Q

Which equations is used to determine the actual operating capacity of a system?

A

Btuh = 4.5 × cfm × the difference in enthalpy between the return and supply air

49
Q

What is known as the “silent killer”?

A

Carbon monoxide

50
Q

___________ ventilation is a control strategy used to maintain a high oxygen content in buildings where a healthy environment is of particular concern.

A

Demand

51
Q

The most economical means of measuring the amount of oxygen deprivation in an occupied space is through the use of a:

A

carbon dioxide sensor

52
Q

What is the natural result of combustion?

A

Carbon dioxide, Water vapor, Carbon monoxide

53
Q

The most serious result of incomplete combustion in any fuel-burning heating device is:

A

Carbon monoxide

54
Q

Carbon monoxide poisoning is often mistaken for:

A

The flu with a headache

55
Q

Carbon monoxide is measured in:

A

PPM

56
Q

Outdoor air intake dampers should be located away from:

A

Busy ground level intersections
Loading docks
Sewer vents

57
Q

Infiltration is air that:

A

enters a space without filtration or control

58
Q

Offgassing is:

A

The release of volatile compounds from products and construction materials

Usually harmful compounds and chemicals, which slowly enter living spaces over time

Chemicals released into the air especially as the host material is heated

59
Q

In the science of indoor air quality VOC stands for:

A

Volatile Organic Compounds

60
Q

Which of the following are common symptoms of carbon monoxide poisoning?

A

Headache and nausea
Fatigue and dizziness
Shortness of breath

61
Q

Nitrogen dioxide is a toxin resulting from:

A

Both the process of combustion and rapid oxidation

62
Q

(T/F) The quality of air indoors can often be worse than that of the outdoors.

A

True

63
Q

Mitigation means to:

A

alleviate

64
Q

Solid particles suspended in air are measured in:

A

Parts per million

65
Q

Which of the following organizations has legal oversight over air quality in the United States?

A

EPA

66
Q

The higher the velocity of the air through a fiber filter, the:

A

Less effective the filtration

67
Q

At what level of indoor air carbon monoxide do most fire departments require emergency personnel to wear self-contained breathing apparatus (SCBA)?

A

50 ppm

68
Q

The function of an ERV is to:

A

Exchange heat between exhaust and intake air

69
Q

ASHRAE standard 55-1992 specifies the conditions likely to be thermally acceptable to _______ of adult occupants of a conditioned space.

A

75%

70
Q

Indoor air quality is legally the responsibility of:

A

The building owner

The business leasing the building

Those operating and maintaining the building

71
Q

Clean rooms are classified according to:

A

The particle count per cubic foot of air

72
Q

HEPA stands for:

A

High Efficiency Particulate Air filter

73
Q

The internal static pressure in a building should be approximately:

A

.05” higher than the outside air pressure

74
Q

Activated charcoal is often satisfactory for the removal of:

A

Gas-phase toxic or odorous pollutants

75
Q

A __________ biological safety cabinet is a gastight negative pressure containment system that provides a physical barrier between the agent and the worker.

A

class 3

76
Q

Is refrigerant oil that has gone through a compressor burn-out classified as a toxic waste?

A

Yes, if the oil contains a substance classified by the EPA as a toxic waste.

77
Q

Three common methods used to mitigate poor indoor air quality are:

A

Filtration, ventilation, and exhaust

78
Q

A micron is:

A

One 25,400th of an inch

79
Q

Bacteria, molds, pollen, and viruses are types of:

A

Biological contaminants

80
Q

According to the World Health Organization approximately what percentage of buildings suffer from SBS (Sick Building Syndrome)?

A

30%

81
Q

A key factor in solving indoor air quality problems is to:

A

Locate and isolate the source of the pollution

82
Q

Which of the following would be the first step in the process of investigating an indoor air quality problem at a building?

A

Defining the perceived problem

83
Q

Physical stressors are those factors that:

A

Can be sensed, felt, seen, or heard

84
Q

Sick Building Syndrome is highly suspected when:

A

20% or more of the building occupants complain with physical symptoms within a 2-week period.

A high degree of occupants call in sick with symptoms of headaches, fatigue, dizziness, coughing, nausea, and eye or throat irritations.

A high degree of occupants find that their symptoms are alleviated by leaving the building.

85
Q

During an initial pre-investigatory building walk-through, which of the following measurements may be taken?

A

Carbon dioxide, temperature, and relative humidity readings

86
Q

What gas originates from manmade materials within a building?

A

Formaldehyde

87
Q

What can affect the intensity of a person’s reaction to an irritant in the air?

A

Temperature and humidity

88
Q

A fairly common but not regularly recognized source of poor indoor air quality and increased dust and residue in homes is:

A

The use of candles

89
Q

What substances has been directly attributed to as many as 20,000 cases of lung cancer in the United States?

A

Radon gas

90
Q

Concentrations of radon gas is measured in:

A

picocuries

91
Q

Particulates are categorized in terms of:

A

Size and source

92
Q

Excessively high concentrations of carbon dioxide in indoor air is usually an indication of:

A

A lack of ventilation air

93
Q

Which of the following IAQ problems was first discovered to have its source in HVAC cooling towers?

A

Legionnella

94
Q

Organic compounds are:

A

Compounds that contain carbon

95
Q

A compound is a:

A

material made up of two or more elements electrically bound to one another

96
Q

TLV stands for:

A

Threshold limit value

97
Q

The average urban outdoor air concentration of carbon dioxide has been determined to be:

A

40 ppm

Heating Service Exam (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions