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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
What is the recommended interval for cleaning ducts?
12 ft intervals.
26
What materials should fasteners for duct doors be made of?
Carbon steel or stainless steel.
27
What clearance should be provided when ducts pass through combustible material?
Not less than 18 inches.
28
What is the fire rating for buildings less than 4 stories?
No less than 1 hour.
29
What is the minimum clearance from outlet to adjacent buildings?
10 ft.
30
What should be the discharge clearance from the outlet to the roof?
Minimum 40 inches.
31
What is the recommended kitchen air velocity in ducts?
Not below 500 fpm and not exceed 2000 fpm.
32
How should exhaust in kitchen systems be interlocked?
With a makeup air unit, not to supply more than 10% of their exhaust capacity.
33
What is the minimum distance between the grease removal device and the cooking surface?
Not less than 18 inches.
34
What is the minimum vertical distance for charcoal type boilers?
4 feet between the lower edge of the grease removal device and the cooking surface.
35
What is the minimal angle that grease filters should be installed from the horizontal?
45°.
36
What are changes to original blueprints called?
Revisions.
37
What are changes to specifications called?
Addenda.
38
What supersedes discrepancies between specifications and blueprints?
The written specs always supersede the drawings.
39
What is the purpose of a maintenance bond?
Guidance against faulty workmanship or materials for a specified period after completion.
40
What is a bid depository?
A fair process for submitting tenders for a specific project.
41
What does ACTS mean in submitting a quote?
Alberta Construction Tendering System.
42
What is the purpose of ACTS?
To provide fair and orderly receipt of bids and protect the tendering process.
43
What percentage of the tender price is the bid bond?
10%.
44
What percentage of the tendered price is the performance bond?
50%.
45
What must a sheet metal worker do before mobilizing on site?
Complete numerous off-site preparation tasks.
46
Why is it a good idea to maintain good scheduling practices?
It can eliminate problems caused by production bottlenecks.
47
What are the purposes of scheduling?
To establish a logical sequence and timeline for tasks.
48
What must you obtain if you vary from the specs on equipment?
Engineer's permission.
49
How is an estimate defined?
An accurate project costing of material and labour.
50
What type of estimating begins three to four years in advance for larger jobs?
Rough order of magnitude (ROM).
51
How much overhang must a commercial kitchen canopy have?
At least 6 inches.
52
What does a Type I hood capture that a Type II does not?
Grease.
53
What are two basic styles of hoods?
Canopy and Non-canopy.
54
List 4 types of canopy hoods.
Island, Wall, Corner, Slotted.
55
List two types of non-canopy hoods.
Back shelf and Eye-Brow.
56
List 4 items that could be part of the grease removal system.
Filters, Baffles, Air washers, UV technology.
57
What is the minimum clearance required for a commercial kitchen exhaust duct?
18 inches
58
What is installed to suppress a flare-up prior to having heat damage?
Fire suppression system
59
In what orientation should commercial kitchen exhaust ducts be installed?
Vertically
60
What is the minimum air velocity through commercial kitchen exhaust?
500 fpm or 152.4 m/minute
61
How much make-up air is required in a commercial kitchen?
100%
62
What is a control interlock panel used for in a commercial kitchen?
To ensure that when the exhaust fan is on, the make-up air unit is also on
63
What can be added to maintain velocity in a constant volume exhaust?
Bypass dampers
64
What 4 provisions must be considered when designing/installing?
Cleaning * Maintenance * Fire protection * Drainage
65
What is the maximum face velocity when exhausting toxic fumes?
60-125 fpm
66
What is another name for an auxiliary air fume hood?
Makeup air fume hood
67
What is incorporated to maintain a desired face velocity on a variable system?
A closed loop control system
68
What is the basic principle on how dilution ventilation works?
Blow clean air in and exhaust dirty air out
69
What is the result of exhausting large amounts of air without a proper system?
Carbon monoxide
70
What builds up in a duct that can increase the risk of flash fire or explosion?
Static electricity
71
What can be used to avoid static buildup in a system?
Aluminum or copper ground wire
72
What is the purpose of a well-designed industrial exhaust system?
Eliminate undesirable contaminants where protection of workers' health is a concern
73
Why do some industrial exhaust systems require special piping or ducting?
There may be the possibility of corrosion or abrasion
74
In what orientation should branches be installed?
On their side or on the top
75
For transitions, every 1 unit of change requires how many units?
5
76
What can be provided for fan outlets if an elbow inlet is necessary?
An inlet box or turning vanes
77
Is it possible to not include certain types of machines when sizing a blower?
Yes
78
What type of duct is used for class 5?
Plastic or stainless
79
Class 5 applications consist of corrosives such as _______.
acid
80
What is the minimum distance a hanger should be from a duct?
At least 2 duct diameters, 4" minimum
81
Why are expansion joints used?
To provide stress relief and absorb movement during extreme temperatures
82
What is a blast gate or slide damper used for?
When a positive seal is desired and to close off or isolate parts of a system
83
Name 3 types of longitudinal seams.
* Groove seam * Butt weld seam * Spiral seam
84
Volume is measured in?
Cubic feet per minute (CFM)
85
What is the minimum distance in inches a draw band joint should have?
4" minimum
86
Which seam can be used for all five duct classes?
Butt weld seam
87
What is the maximum Center to Center distance for screws or rivets?
6 inches
88
How many inches of lap should there be on commercial pipe?
2 inches
89
Class 1 only and 2 gauges heavier than chart values describe what?
Aluminum duct
90
Elbows should have a centreline radius of what?
No less than twice but preferably 2.5 times the pipe diameter
91
All branches should enter the main duct at what angle?
Not to exceed 45 degrees with 30 degrees being preferred
92
What are explosion doors used for?
To provide instantaneous pressure discharge
93
What are the two broad categories of Type I hoods?
Standard and Listed
94
What type of pressure is found in a local exhaust ventilation duct?
Slightly negative pressure
95
What occurs if face velocity in a hood exceeds 125 fpm?
Turbulence
96
What is a blast gate also known as?
Slide damper
97
When is plastic or PVC duct used on an industrial exhaust system?
For corrosive or toxic fumes are to be conveyed
98
What is the best practice regarding centreline radius and number of gores?
Centreline of 2.5 and 7 gores
99
What can be added to maintain velocity in a constant volume exhaust system?
Bypass dampers
100
What takes precedence over original drawings and specifications?
Addenda and Revisions
101
What gauge of mild steel can be used in the construction of a commercial kitchen?
16 gauge mild steel ## Footnote This specification is important for ensuring structural integrity.
102
What gauge of mild steel is specified for other constructions?
18 gauge mild steel ## Footnote This is typically used for less demanding structural applications.
103
At what length on a commercial kitchen exhaust canopy is it desirable to have specific design considerations?
When the canopy exceeds 10' ## Footnote This length may require additional structural or design elements.
104
Where shall access doors be located for the purpose of cleaning and inspection in commercial kitchens?
Side or top ## Footnote Access doors are crucial for maintenance and safety.
105
How much extra weight needs to be accounted for in commercial kitchen exhaust systems?
800 lbs ## Footnote This weight consideration is critical for proper structural support.
106
How much clearance must a commercial kitchen exhaust duct have?
18"
107
What does BIM stand for?
Building Information Management ## Footnote BIM is a digital representation of physical and functional characteristics of a facility.
108
What must carefully be studied when compiling a job takeoff?
The plans and specifications ## Footnote This ensures accuracy in estimating quantities and costs.
109
What is ACTS?
The Alberta Construction Tendering System ## Footnote ACTS is used for managing construction tenders in Alberta.
110
What does a bid bond guarantee?
That if the contractor is the low bidder, they will honor the bid ## Footnote A bid bond protects the project owner from a contractor's failure to execute the contract.
111
What is the purpose of a spec?
To describe the work to be done ## Footnote Specifications provide detailed information on materials, methods, and quality standards.
112
What is the purpose of a schedule?
To provide information on what goes where ## Footnote Schedules outline the timeline and sequence of construction activities.
113
What is a change to a blueprint called?
A revision ## Footnote Revisions reflect updates or corrections made to original plans.

Austin's Sheet Metal 4th Year (7 decks)

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