2nd Volume - HVAC/R Fundamentals Flashcards
(132 cards)
1
Q
What is the most common cause of electric shock?
A
extension cord abuse
2
Q
What are two basic groups of safety directives that apply to the HVAC/R career field?
A
AFIs and Air Force Occupational Safety and Health (AFOSH) standards
3
Q
What directive states safety policy, sets up mishap prevention program requirements, and assigns responsibilities for program elements?
A
AFI 91–202, The USAF Mishap Prevention Program
4
Q
Which regulation establishes policy and assigns responsibilities for managing the AFOSH program and applies to all Air Force civilian and military personnel worldwide, including members of the Air National Guard and Air Force Reserve?
A
AFI 91–301, Air Force Occupational and Environmental Safety, Fire Protection and Health (AFOSH) Program
5
Q
Which regulation prescribes safe practices and procedures for personnel engaged in maintaining and operating electrical systems and facilities?
A
AFI 32–1064, Electrical Safe Practice.
6
Q
What has the Air Force set up to protect personnel from the harmful effects of hazardous noise?
A
Hearing Conservation Program
7
Q
A hazardous noise exists if you have to —BLANK— to be understood.
A
shout at 3 feet (a loud voice at 1 foot)
8
Q
When working on circuits over —BLANK—, workers must not work alone; instead, a safety observer must be present.
A
300 volts
9
Q
What are the four basic causes of burns?
A
Thermal, Chemical, Electrical, and Nuclear
10
Q
Which burns are caused by excessive heat?
A
Thermal
11
Q
What are the three categories of thermal burn damage?
A
First, Second, and Third Degree
12
Q
Which burn classification is normally associated with sunburns where there’s a reddening of the skin but doesn’t blister or burn through the different layers of skin?
A
First degree
13
Q
Which burns are characterized by blisters appearing on the first layer of skin?
A
Second degree
14
Q
Which is the most severe burn a person can get and damages the skin through the top layer and sometimes through the fat that lies beneath it?
A
Third degree
15
Q
Which burn destroys the nerve endings?
A
Third degree
16
Q
What happens to the area of a third degree burn?
A
becomes dry, leathery, and discolored (charred, brown, or white)
17
Q
What are two types of cross connections?
A
Inlet and Direct (or pressure)
18
Q
What is any actual or potential link or path of flow between a potable water supply and a source of contamination or pollution?
A
cross connection
19
Q
What type of connection is used to fill a receptacle that’s open to the atmosphere?
A
Inlet-type connection
20
Q
What is the reversal of the normal water flow in a system?
A
Back-siphonage
21
Q
What is the reversal of the normal water flow in a system caused by a negative pressure in the supply piping?
A
Back-siphonage
22
Q
What type of connection is one in which the potable waterline is connected to a nonpotable line or pressurized vessel?
A
Direct-or pressure-type connection
23
Q
The backflow of —BLANK— into a potable water supply would cause a minor change in the water quality
A
a Class I substance
24
Q
The backflow of —BLANK— into a potable water supply could cause illness or death if consumed by humans.
A
a Class III substance
25
What are the five types of backflow prevention devices?
1. Air gap, 2. Atmospheric-type vacuum breaker, 3. Pressure-type vacuum breaker, 4. Double check valve, 5. Reduced pressure backflow preventer
26
What is a physical separation of the potable and nonpotable system by an air space?
Air Gap
27
For an air gap to work properly, the vertical space between the supply line and the flood-level rim must be at least
two times the inside diameter of the supply pipe and it can’t be less than 1 inch and need not be more than 12 inches
28
Which type of breaker is designed to prevent back-siphonage of Class I substances into a potable water supply?
Atmospheric-type vacuum breaker or Pressure-type vacuum breaker
29
Which type of breaker prevents a vacuum from occurring on the discharge line by allowing air to enter the line?
Atmospheric-type vacuum breaker
30
Which breaker must be installed on the discharge side of the last control valve and above the highest usage point?
Atmospheric-type vacuum breaker
31
Which breaker can’t be used under continuous pressure or be subjected to backpressure?
Atmospheric-type vacuum breaker
32
Which breaker device has a moving, spring-loaded disc float and check valve in the body?
Pressure-type vacuum breaker
33
Which device is used in direct connection-type systems to prevent the backflow of Class I and II substances into the potable water supply?
Double check valve
34
What valve can be used in continuous pressure systems that are subject to backpressure or back-siphonage?
Double check valve
35
Which device has two independently operating, spring-loaded check valves in the body?
Double check valve
36
Which type of backflow preventer may be used on all direct connection-type systems?
reduced pressure backflow preventer
37
What type of backflow preventer is designed to prevent the backflow of all three classes of substances into the potable water supply?
reduced pressure backflow preventer
38
Which backflow preventer is used in continuous pressure systems that are subject to backpressure or backsiphonage?
reduced pressure backflow preventer
39
Which backflow preventer is equipped also with two independently operating spring-loaded check valves, which are located in the body?
reduced pressure backflow preventer
40
Who is responsible for reporting unsafe acts or conditions?
Everyone
41
Which AFI covers areas relating to electrical installations and systems?
32-1064
42
Which AFOSH standard covers areas relating to working around machinery?
91-12
43
Select the statement that best describes your individual responsibility relative to the Air
Force Occupational Safety and Health (AFOSH) program?
Report safety, fire, and health hazards promptly.
44
Leaving tools scattered about is an indication of
Poor housekeeping
45
What types of mishaps must be reported to the safety staff?
All mishaps
46
Select the Air Force program that was established to protect personnel from the harmful effects of hazardous noise.
Hearing Conservation Program.
47
What is the best protection against noise damage?
Isolate systems or pieces of equipment that exceed acceptable noise limits.
48
A safety observer must be present if you are working with a voltage over
300 volts
49
Mechanical equipment that has exposed moving parts must be completely enclosed in a suitable metal guard if the equipment is located above the floor by less than
8 feet
50
When working on rotating equipment, you should avoid
wearing loose clothing
51
Second-degree burns are characterized by
blisters appearing on the first layer of skin
52
When a thermal burn victim has had his or her clothes on fire, and the skin and clothes are still hot, you should immerse them in
cold water for a maximum of 10 minutes
53
Which burn treating statement is correct?
Cover the burned area with a dry, sterile dressing to decrease heat loss
54
What type of cross connection exists if the spout on a sink faucet extends below the overflow rim?
Inlet
55
Which type of backflow preventer is used to prevent back-siphonage of Class I substances and may be used under continuous pressure but not subjected to back-pressure?
Atmospheric-type vacuum breaker.
56
Which type of backflow preventer can be used on all direct connection-type systems to
prevent the backflow of all three classes of substances into the potable water supply?
Reduced pressure backflow preventer.
57
Which backflow preventer is used in continuous pressure systems that are subject to backpressure or backsiphonage?
reduced pressure backflow preventer
58
Which backflow preventer is equipped also with two independently operating spring-loaded check valves, which are located in the body?
reduced pressure backflow preventer
59
The size of a pipe is referred to as
nominal
60
What are the two grades of steel pipe?
1. Standard, or schedule 40, 2. Extra strong (or heavy), or schedule 80
61
What are the most commonly used materials for piping?
Steel, Iron, Copper, and Plastic
62
What is galvanized pipe is coated with?
zinc
63
What is galvanized pipe mostly used for?
domestic water applications
64
What piping does HVAC/R technicians primarily deal with?
black iron piping
65
What are the four most common types of fittings used in HVAC/R systems?
1. Thread, 2. Flange, 3. Flared, 4. Compression Joint
66
What type of fittings are used mostly on steel piping?
Thread and flanges
67
What type of joints are used with copper lines?
Flared and compression
68
How are pipe fittings measured?
by Inside Diameter, not outside diameter
69
What is the main method for joining small diameter pipe?
Threading
70
What limits the threading for various refrigerants and pipe sizes?
ASME Standard B31.5, Refrigeration Piping
71
Pipe with a wall thickness ---BLANK--- than ---BLANK--- should not be threaded.
Less, standard weight
72
What fittings can be used for large pipe and all piping materials?
Flange fittings
73
What fittings are commonly used to connect to equipment, valves, and wherever it may be necessary to open the joint to permit service or replacement of components?
Flange fittings
74
For steel pipe, flanges are available in a pressure rating to ---BLANK---
2,500 psig
75
What three tasks are performed when preparing pipe for fabrication?
1. Measure the pipe, 2. cut the pipe, 3. thread the pipe
76
What fabrication tasks will ensure a minimum of improper or defective connections, and ensure there is a minimum leakage and loss of fluid?
1. Measure the pipe, 2. cut the pipe, 3. thread the pipe
77
What are three methods of measuring pipe?
1. End-to-center, 2. end-to-end, 3. center-to-center
78
Which pipe measurement is taken from the center of an elbow or tee screwed on one end to the opposite end of the pipe?
End-to-center
79
Which pipe measurement is made by first tightening an elbow on the threaded end of a pipe?
End-to-center
80
Which pipe measurement is made without any fittings?
End-to-end
81
What measurements are usually shown on pipe drawings?
Center-to-center
82
Which pipe measurement is the distance between the centers of two fittings in a line of pipe?
Center-to-center
83
What is the first thing you do when making a center-to-center measurement?
put a fitting on the end of the pipe
84
To cut a pipe with a pipe cutter, first open the jaws of the cutter by turning the handle ---BLANK---
Counterclockwise
85
After the wheels contact the pipe on a pipe cutter, rotate the handle ---BLANK---
one-fourth of a turn in a clockwise direction
86
When using a pipe cutter, what puts a "bite" on the pipe causing a groove in the pipe when the cutter is rotated?
rotating the handle one-fourth of a turn in a clockwise direction
87
When using a pipe cutter, what happens if you do not rotate the pipe cutter one turn to make a complete cutting mark around the pipe before turning the handle clockwise to make the cut deeper?
The pipe cutter will make spiral marks around the pipe instead of making on complete circle
88
What happens if you do not remove the burr from a threaded pipe?
The burr hinders the flow of liquids or gases in the pipe
89
What is used to remove a burr from the end of a threaded pipe?
A pipe reamer
90
What are two methods of threading pipe?
Hand and power threading
91
How many threads should be made on pipe with a size of 1/8 inch
27 Threads per inch
92
How many threads should be made on pipe with a size of 1/8 inch
27 Threads per inch
93
How many threads should be made on pipe with a size of 1/4 to 3/8 inch
18 Threads per inch
94
How many threads should be made on pipe with a size of 1/2 to 3/4 inch
14 Threads per inch
95
How many threads should be made on pipe with a size of 1 to 2 inches
11.5 threads per inch
96
How many threads should be made on pipe with a size of 2.5 to 12 inches
8 threads per inch
97
When using a power threader, how far do you insert the pipe into the chuck?
so it protrudes about 8 inches beyond the face of the chuck
98
What are two important factors of pipe fabrication?
1. Assembly of threaded joints, 2. Pipe expansion and flexibility
99
During pipe fabrication, what must be done to attain ample flexibility to accommodate thermal and other movements?
Disigning pipe bends and loops or using supplemental devices such as expansion joints
100
What can happen if you fail to design piping to accommodate thermal and other movements?
1. Failure of pipe and support from over-stress and fatigue, 2. Joint leakage, 3. Detrimental forces and stresses in connected equipment.
101
Copper tubing may be ---BLANK---
Hard drawn or annealed
102
Which copper pipe comes in 20 foot lengths?
hard drawn copper pipe
103
Which tubing is soft-tempered and comes in rolls?
Annealed copper tubing
104
For refrigeration systems, how is tubing size measured?
using outside diameter (OD)
105
What is the difference between plumbing tubing application sizing and refrigeration sizing?
plumbing uses Inside diameter, while refrigeration uses outside diameter
106
How are heating tubing applications sized?
The same as plumbing, using inside diameter (ID) - AKA "nominal-size tubing"
107
What types of tubing are mostly used on waterlines?
nominal-sized tubing - K and L
108
Outside diameter tubing is normally how much bigger than plumbing tubing?
1/8 inch
109
7/8 inch outside diameter (OD) tubing for refrigeration is equal to what Inside Diameter (ID) for plumbing?
3/4 inch
110
What are the three types of copper tubing mostly used in HVAC/R?
1. K, 2. L, and 3. ACR
111
What is used to identify K type copper pipe?
A green-colored band and a stencil on the surface
112
Which copper pipe has the thickest wall?
K type
113
Which copper is mostly hard drawn but can be soft temper?
K type
114
What is used to identify L type copper pipe?
A blue-colored band and a stencil on the surface
115
Which copper is used for recirculating water, refrigerant, and potable water inside buildings?
L Type
116
How can L copper be purchased?
20 feet hard drawn or 25 to 100 feat annealed (soft) coils
117
What is on ACR tubing when it is purchased or new?
Plugs on the ends
118
What do the plugs on the ends of ACR tubing indicate?
That the tubing has been dried and charged with nitrogen from the factory
119
What is the purpose of the plugs (or seals) on the ends of new ACR tubing?
to reduce oxidation within the tube
120
What type of stainless steel tubing is mostly used in the refrigeration trade?
low-carbon, nickel, and chromium stainless steel
121
Why is aluminum being used in refrigeration systems?
because it is lightweight and has a high heat conductivity rating
121
Why is aluminum being used in refrigeration systems?
because it is lightweight and has a high heat conductivity rating
122
What fittings are used when an item needs to be readily replaced or the system needs to be leak-free?
Flare
122
What fittings are used when an item needs to be readily replaced or the system needs to be leak-free?
Flare
123
What fitting is used when you need a permanent connection (or fix)?
Sweat (or solder) fitting
123
What fitting is used when you need a permanent connection (or fix)?
Sweat (or solder) fitting
124
What are the two basic types of tube benders?
1. Bending springs, 2. Lever type
124
What are the two basic types of tube benders?
1. Bending springs, 2. Lever type
125
Which tubing bender can be used when you don't need a high degree of accuracy?
Bending spring
125
Which tubing bender can be used when you don't need a high degree of accuracy?
Bending spring
126
Which tool is used to make tubing bends when a high degree of accuracy is required?
Lever-type bender
126
Which tool is used to make tubing bends when a high degree of accuracy is required?
Lever-type bender
