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Austin's Sheet Metal 4th Year > Commercial HVAC TQ Prep > Flashcards

Commercial HVAC TQ Prep Flashcards

1
Q

What should be the size of the cheeks for a rectangular roof ventilator?

A

Cheeks should be 25% bigger than the bottom opening.

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2
Q

What is the recommended face velocity for a hood under normal conditions?

A

100 fpm

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3
Q

What should be the ducting configuration for exhaust ducts entering fans?

A

Ducting should be straight for at least 2 diameters before it enters the fan.

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4
Q

What are axial fans typically used for?

A

Commonly used for dilution ventilation.

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5
Q

Why are centrifugal fans preferred for exhausting heavy amounts of dust?

A

They are less likely to become clogged.

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6
Q

What are heavy material handling wheels designed for?

A

Used for handling air with small wood block pieces or similar solid materials.

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7
Q

What is the purpose of material handling wheels?

A

To prevent long fibrous or stringy materials from wrapping around the blades.

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8
Q

What are air handling wheels used for?

A

Only for clean air, not for handling materials.

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9
Q

What is the recommended distance for exhaust stacks from fresh air intakes in commercial exhaust?

A

Should not be located closer than 50 feet.

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10
Q

What is the recommended elbow radius for ductwork?

A

Preferably 2½ times the pipe diameter.

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11
Q

What is the maximum angle for branches entering the main duct?

A

Not exceeding 45°, with 30° being recommended.

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12
Q

How should transitions in ductwork be designed?

A

Always be tapered, 1 unit of change for every 5 units of change in length.

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13
Q

What is the recommended clearance between fan and inlet obstruction?

A

Greater than ½ wheel diameter.

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14
Q

When is forced air mechanical ventilation required?

A

When workers enter confined spaces with exposure to toxic or flammable vapors, dust, or oxygen deficiency.

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15
Q

What is the air velocity out of an exhaust stack?

A

Should be 3000 fpm.

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16
Q

What may be required if a stack extends more than 10 feet above a roof?

A

Guy wire, minimum 3 of them.

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17
Q

What is the minimum air velocity through commercial kitchen exhaust ducts?

A

500 fpm or 154.2 meters/minute.

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18
Q

What is one of the most important factors in a proper duct collection system?

A

The hood design.

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19
Q

How should exhaust system dust collection elbows be constructed?

A

Should be 2 gauges heavier than straight pipe.

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20
Q

What is the kitchen exhaust canopy code material?

A

18ga mild steel or stainless steel.

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21
Q

What is the recommended cleaning access for duct elbows and transitions?

A

An opening large enough for cleaning should be at each elbow, change, or transition.

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22
Q

Where should clean outs on ducts be located?

A

On the sides or top, not on the bottom.

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23
Q

What is the minimum distance for non-listed ductwork openings from outside edges?

A

Not less than 1½ inches.

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24
Q

What is the recommended size for personal inspection and cleaning access openings?

A

20”x20”.

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25
Q

What is the recommended interval for cleaning ducts?

A

12 ft intervals.

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26
Q

What materials should fasteners for duct doors be made of?

A

Carbon steel or stainless steel.

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27
Q

What clearance should be provided when ducts pass through combustible material?

A

Not less than 18 inches.

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28
Q

What is the fire rating for buildings less than 4 stories?

A

No less than 1 hour.

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29
Q

What is the minimum clearance from outlet to adjacent buildings?

A

10 ft.

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30
Q

What should be the discharge clearance from the outlet to the roof?

A

Minimum 40 inches.

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31
Q

What is the recommended kitchen air velocity in ducts?

A

Not below 500 fpm and not exceed 2000 fpm.

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32
Q

How should exhaust in kitchen systems be interlocked?

A

With a makeup air unit, not to supply more than 10% of their exhaust capacity.

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33
Q

What is the minimum distance between the grease removal device and the cooking surface?

A

Not less than 18 inches.

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34
Q

What is the minimum vertical distance for charcoal type boilers?

A

4 feet between the lower edge of the grease removal device and the cooking surface.

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35
Q

What is the minimal angle that grease filters should be installed from the horizontal?

A

45°.

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36
Q

What are changes to original blueprints called?

A

Revisions.

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37
Q

What are changes to specifications called?

A

Addenda.

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38
Q

What supersedes discrepancies between specifications and blueprints?

A

The written specs always supersede the drawings.

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39
Q

What is the purpose of a maintenance bond?

A

Guidance against faulty workmanship or materials for a specified period after completion.

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40
Q

What is a bid depository?

A

A fair process for submitting tenders for a specific project.

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41
Q

What does ACTS mean in submitting a quote?

A

Alberta Construction Tendering System.

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42
Q

What is the purpose of ACTS?

A

To provide fair and orderly receipt of bids and protect the tendering process.

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43
Q

What percentage of the tender price is the bid bond?

A

10%.

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44
Q

What percentage of the tendered price is the performance bond?

A

50%.

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45
Q

What must a sheet metal worker do before mobilizing on site?

A

Complete numerous off-site preparation tasks.

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46
Q

Why is it a good idea to maintain good scheduling practices?

A

It can eliminate problems caused by production bottlenecks.

47
Q

What are the purposes of scheduling?

A

To establish a logical sequence and timeline for tasks.

48
Q

What must you obtain if you vary from the specs on equipment?

A

Engineer’s permission.

49
Q

How is an estimate defined?

A

An accurate project costing of material and labour.

50
Q

What type of estimating begins three to four years in advance for larger jobs?

A

Rough order of magnitude (ROM).

51
Q

How much overhang must a commercial kitchen canopy have?

A

At least 6 inches.

52
Q

What does a Type I hood capture that a Type II does not?

A

Grease.

53
Q

What are two basic styles of hoods?

A

Canopy and Non-canopy.

54
Q

List 4 types of canopy hoods.

A

Island, Wall, Corner, Slotted.

55
Q

List two types of non-canopy hoods.

A

Back shelf and Eye-Brow.

56
Q

List 4 items that could be part of the grease removal system.

A

Filters, Baffles, Air washers, UV technology.

57
Q

What is the minimum clearance required for a commercial kitchen exhaust duct?

A

18 inches

58
Q

What is installed to suppress a flare-up prior to having heat damage?

A

Fire suppression system

59
Q

In what orientation should commercial kitchen exhaust ducts be installed?

A

Vertically

60
Q

What is the minimum air velocity through commercial kitchen exhaust?

A

500 fpm or 152.4 m/minute

61
Q

How much make-up air is required in a commercial kitchen?

A

100%

62
Q

What is a control interlock panel used for in a commercial kitchen?

A

To ensure that when the exhaust fan is on, the make-up air unit is also on

63
Q

What can be added to maintain velocity in a constant volume exhaust?

A

Bypass dampers

64
Q

What 4 provisions must be considered when designing/installing?

A

Cleaning * Maintenance * Fire protection * Drainage

65
Q

What is the maximum face velocity when exhausting toxic fumes?

A

60-125 fpm

66
Q

What is another name for an auxiliary air fume hood?

A

Makeup air fume hood

67
Q

What is incorporated to maintain a desired face velocity on a variable system?

A

A closed loop control system

68
Q

What is the basic principle on how dilution ventilation works?

A

Blow clean air in and exhaust dirty air out

69
Q

What is the result of exhausting large amounts of air without a proper system?

A

Carbon monoxide

70
Q

What builds up in a duct that can increase the risk of flash fire or explosion?

A

Static electricity

71
Q

What can be used to avoid static buildup in a system?

A

Aluminum or copper ground wire

72
Q

What is the purpose of a well-designed industrial exhaust system?

A

Eliminate undesirable contaminants where protection of workers’ health is a concern

73
Q

Why do some industrial exhaust systems require special piping or ducting?

A

There may be the possibility of corrosion or abrasion

74
Q

In what orientation should branches be installed?

A

On their side or on the top

75
Q

For transitions, every 1 unit of change requires how many units?

A

5

76
Q

What can be provided for fan outlets if an elbow inlet is necessary?

A

An inlet box or turning vanes

77
Q

Is it possible to not include certain types of machines when sizing a blower?

A

Yes

78
Q

What type of duct is used for class 5?

A

Plastic or stainless

79
Q

Class 5 applications consist of corrosives such as _______.

A

acid

80
Q

What is the minimum distance a hanger should be from a duct?

A

At least 2 duct diameters, 4” minimum

81
Q

Why are expansion joints used?

A

To provide stress relief and absorb movement during extreme temperatures

82
Q

What is a blast gate or slide damper used for?

A

When a positive seal is desired and to close off or isolate parts of a system

83
Q

Name 3 types of longitudinal seams.

A
  • Groove seam * Butt weld seam * Spiral seam
84
Q

Volume is measured in?

A

Cubic feet per minute (CFM)

85
Q

What is the minimum distance in inches a draw band joint should have?

A

4” minimum

86
Q

Which seam can be used for all five duct classes?

A

Butt weld seam

87
Q

What is the maximum Center to Center distance for screws or rivets?

A

6 inches

88
Q

How many inches of lap should there be on commercial pipe?

A

2 inches

89
Q

Class 1 only and 2 gauges heavier than chart values describe what?

A

Aluminum duct

90
Q

Elbows should have a centreline radius of what?

A

No less than twice but preferably 2.5 times the pipe diameter

91
Q

All branches should enter the main duct at what angle?

A

Not to exceed 45 degrees with 30 degrees being preferred

92
Q

What are explosion doors used for?

A

To provide instantaneous pressure discharge

93
Q

What are the two broad categories of Type I hoods?

A

Standard and Listed

94
Q

What type of pressure is found in a local exhaust ventilation duct?

A

Slightly negative pressure

95
Q

What occurs if face velocity in a hood exceeds 125 fpm?

A

Turbulence

96
Q

What is a blast gate also known as?

A

Slide damper

97
Q

When is plastic or PVC duct used on an industrial exhaust system?

A

For corrosive or toxic fumes are to be conveyed

98
Q

What is the best practice regarding centreline radius and number of gores?

A

Centreline of 2.5 and 7 gores

99
Q

What can be added to maintain velocity in a constant volume exhaust system?

A

Bypass dampers

100
Q

What takes precedence over original drawings and specifications?

A

Addenda and Revisions

101
Q

What gauge of mild steel can be used in the construction of a commercial kitchen?

A

16 gauge mild steel

This specification is important for ensuring structural integrity.

102
Q

What gauge of mild steel is specified for other constructions?

A

18 gauge mild steel

This is typically used for less demanding structural applications.

103
Q

At what length on a commercial kitchen exhaust canopy is it desirable to have specific design considerations?

A

When the canopy exceeds 10’

This length may require additional structural or design elements.

104
Q

Where shall access doors be located for the purpose of cleaning and inspection in commercial kitchens?

A

Side or top

Access doors are crucial for maintenance and safety.

105
Q

How much extra weight needs to be accounted for in commercial kitchen exhaust systems?

A

800 lbs

This weight consideration is critical for proper structural support.

106
Q

How much clearance must a commercial kitchen exhaust duct have?

A

18”

107
Q

What does BIM stand for?

A

Building Information Management

BIM is a digital representation of physical and functional characteristics of a facility.

108
Q

What must carefully be studied when compiling a job takeoff?

A

The plans and specifications

This ensures accuracy in estimating quantities and costs.

109
Q

What is ACTS?

A

The Alberta Construction Tendering System

ACTS is used for managing construction tenders in Alberta.

110
Q

What does a bid bond guarantee?

A

That if the contractor is the low bidder, they will honor the bid

A bid bond protects the project owner from a contractor’s failure to execute the contract.

111
Q

What is the purpose of a spec?

A

To describe the work to be done

Specifications provide detailed information on materials, methods, and quality standards.

112
Q

What is the purpose of a schedule?

A

To provide information on what goes where

Schedules outline the timeline and sequence of construction activities.

113
Q

What is a change to a blueprint called?

A

A revision

Revisions reflect updates or corrections made to original plans.

Austin's Sheet Metal 4th Year (13 decks)

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