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0
Q
  1. Density of ice?
A

57.4 lb/cu.ft.

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1
Q
  1. The weight of a unit volume of substance?
A

Density.

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2
Q
  1. Density of air?
A

.075 lb/cu.ft.

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3
Q
  1. Density of copper?
A

552 lb/cu.ft.

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4
Q
  1. Density of steel?
A

489.5 lb/cu.ft.

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5
Q
  1. Density of lead?
A

710 lb/cu.ft.

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6
Q
  1. Density of mercury?
A

849 lb/cu.ft.

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7
Q
  1. How are all substances composed?
A

Elements are the basic materials of which all substances are composed.

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8
Q
  1. How many elements are known to exist?
A

Currently, there are 115 elements.

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9
Q
  1. Name parts of periodic table of the elements?
A
  1. The vertical columns called periods.

2. Horizontal rows - groups.

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10
Q
  1. Name groups of periodic table of the elements?
A
  1. Alkali metals.
  2. Alkaline earth metals.
  3. Transition metals.
  4. Nonmetals.
  5. Inert gases.
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11
Q
  1. What is rare earth elements?
A

Elements which differ in electron configuration from that of the next lower or higher atomic number only in the number of electrons in the second from the outside shell.

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12
Q
  1. What is a transition element?
A

An element which differs one lectern configuration from that of the next lower or higher atomic number only in the number of electrons in the next to the outside shell.

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13
Q
  1. How is the atomic weight of an element based on?
A

The total number of protons and neutrons in the nucleus of the atom.

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14
Q
  1. What is general similarity between atomic weights of various elements and the densities of the same elements?
A

The weight of a specific volume of each element would remain in the order shown on the periodic table.

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15
Q
  1. How are all elements composed?
A

Of atoms.

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16
Q
  1. What is an atom?
A

The smallest particle of an element which can exist either alone or in combination with other elements.

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17
Q
  1. Definite regions - energy levels or orbits in which electrons move about the nucleus?
A

Shells.

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18
Q
  1. How is acetylene stored?
A

In a liquid, acetone.

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19
Q
  1. What is molecule?
A

The smallest part of either an element or compound which retains the properties of the original substance.

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20
Q
  1. What is heat?
A

A form of energy due to the molecular motion of substance. A measure of the total kinetic energy of all the molecules contained in the substance.

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21
Q
  1. Range of thermometers?
A
  1. Alcohol - for low temperature work.
  2. Mercury - up to 400*F.
  3. Pyrometers (the space above the mercury is filled with an inert gas under pressure) - from -60F
    to 1000    F.
  4. Electric resistance pyrometers - from -330F to 1300F.
  5. Metallic thermometer.
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22
Q
  1. How much space does stern require under the same temperature as water?
A

About 380 times as much.

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23
Q
  1. How does water expend when heat is applied?
A

At the rate of approximately .00023%for each degree of temperature rise.

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24
40. How does water expand when it freezes?
1/12 its volume.
25
41. When are Rankine and Kelvin temperature scales used?
When working with gases whenever pressure and volume are part of the calculations.
26
44. How are heat calculations, involving a large number of Btu as with the Btu output of a large capacity steam generator?
In therms: 1 therm is equal to 100,000 Btu.
27
46. What are average temperatures of cold water and setting on a water heater?
55*F and 140*F.
28
49. What are three terms that directly related to a temperature change in a known substance where the three states of matter are involved?
1. Specific heat. 2. Sensible heat. 3. Latent heat.
29
51. What is specific heat of water. Air alcohol and steam?
1, 0.24, 0.602, 0.48.
30
52. What is specific heat of a substance?
The ratio of its heat capacity to that of water.
31
54. The formula to determine the quantity of sensible heat required to raise or lower the temperature of any substance?
``` H=SxWx(T1-T2) H-Btu of sensible heat, S-specific heat, W-weight in pounds (T1-T2)- temperature difference. ```
32
55. How much heat is required to raise the temperature of 100 lb of ice from 20*F to 32*F?
The specific heat of ice is 0.5. | H=0.5x100x(32-20)=600 Btu.
33
57. More convenient formula for computing Btu/hr?
H(H2O Btu/hr) = 500xO(gpm)x(T1-T2).
34
58. If 970 cfm of air flows across the heating coil of a unit heater and the temperature of the air increases from 70* to120*F, how many Btu of heat are transferred per hour?
W=970cfm x .075 lb/cu. ft. x 60min/hr = 4365 lb/hr. | H=.24x4365x(120-70)=52.380 Btu/hr.
35
60. What is the total amount of heat that must be added to one pound of ice at 0*F to convert it to steam at 212*F?
``` 1 lb of ice at 0*F to 32*F - 16 Btu. 1 lb of ice at 32* to water - 144Btu 1 lb of water at 32* to212*-180Btu. 1 lb of water at 212* to steam - 970.4 Btu. All together:1,310.4 Btu - 1 lb ice at 0*F to steam at 212*F. ```
36
61. How is the process of changing from the solid to the liquid state called?
1. Fusion. 2. Melting. 3. Liquefaction.
37
62. How is the temperature at which the solid change to the liquid called?
The melting point.
38
63. What substances do not have a definite melting point?
Non crystalline substances such as glass, wrought iron, and solder.
39
64. How is the latent heat that is added to cause a change of state from a solid to a liquid called?
The latent heat of fusion or the latent heat of melting.
40
65. Melting and freezing point plumbing substances?
``` Wrought iron - 2732-2912*F. Steel - 2588*F. Copper - 1983*F. Brass - 1866*F. Bronze - 1688*F. Lead - 620*F. Tin - 449*f. Ice - 32*F ```
41
66. The law of heat exchange?
The total number of Btu lost by the warmer substance whisks the total number of Btu gained by the cooler substance. Heat lost = heat gained.
42
67. What is the unit ton of refrigeration?
The heat absorbed by the melting of a ton (2000 pounds) of ice in an 1 hour period: 12,000 Btu per hour.
43
68. What is the flow of air (cfm) that must pass the hot water heating coil, if the temperature drop is 40*F. The water flow rate is 10 gpm and the air temperature increases from 60* to 130*F?
Heat loss=heat gain. H(water)=500xO(gpm )x^T=500x10x40=200,000. H(air)=1.08xO(cfm)x^T=200,000. O(cfm)=200,000/1.08/^T=200,000/(1.08x70)=2645.5 cfm.
44
69. How is the process of converting a liquid into a vapor called?
Vaporization.
45
70. Different forms of vaporization?
1. Boiling. 2. Evaporation. 3. Flashing.
46
71. What is boiling?
All of the liquid is hot enough so bubbles reach the surface freely, vaporization occurs throughout the liquid with visible disturbance.
47
72. Boiling points plumbing substances?
1. Zinc -1,661*F. 2. Mercury-675*F. 3. Water - 212*F. 4. Alcohol - 173*F. 5. Freon - (-21.7)*F. 6. Ammonia - (-28)*F.
48
75. What is the name of the latent heat involved in a change of state from a liquid to a visor, or vice versa?
The latent heat of vaporization.
49
76. What is the latent heat of vaporization of water at sea level?
970.4 Btu.
50
77. How many must Btu of heat be removed from each pound of water vapor to cause it to condense to a liquid?
970.4 Btu at sea level.
51
78. What is meant by the term evaporation?
Process of changing a liquid to a gas below the saturation temperature and only at the surface of the liquid
52
79. Factors which govern the rate of evaporation?
1. The extent of the free surface of the liquid. 2. The temperature. 3. The pressure exerted upon the surface of the liquid. 4. The degree of saturation of the space above the liquid. 5. The volatility of the liquid. 6. The number of air changes.
53
80. Cooling of water as the water evaporates when air blow across it speeded surface?
Evaporative cooling.
54
81. Give an example of evaporative cooling and how it can be used to cool condenser water?
The cooling tower is used to cool condenser water so it may be recirculated again. The water is sprayed through the cooling tower where a portion of it evaporates. The evaporation removes the heat from the remaining portion of water.
55
83. The temperature and pressure hot condensate at the steam trap inlet?
15 psig and 250*F.
56
84. How do liquids and solids expand on heating?
Liquids have higher coefficients of expansion.
57
85. How does mercury expand on heating?
It is fairly uniform between 32*F and 212*F.
58
86. The coefficient of water expansion?
0.00024.
59
87. Formula for expansion volume?
``` EV = V1x(T1-T2)xCE. EV-expansion volume. V1-original volume. ^T-temperature change. CE-coefficient of expansion. ```
60
88. One hundred gallons of gasoline are measured at 32*F. What will be the increase in volume of the gasoline at 86*F?
EV = 100x(86-32)x0.0006 = 3.24 gal.
61
89. What is the value of the coefficient of cubical expansion for all gases?
.002035 per 1 degree Fahrenheit.
62
90. The gas low?
The absolute pressure exerted by a gas is in direct proportion to the absolute temperature: P2 = P1xT1/T2.
63
91. 10 cubic feet of air is heated from 60*F to 180*F at a constant volume. What is the final pressure if the initial pressure is 20 psig?
P2 = (20+14.7)x(180+460)/(60+460) = 42.7 psia =42.7-14.7 = 28 psig.
64
94. The combination gas law?
P1xV1/T1 = P2xV2/T2.
65
95. A gas occupies a volume of 6 cubic feet at standard temperature and pressure. What volume will it occupy when the pressure is 15 psig and the temperature is 80*F?
V2 = P1xV1xT2/(P2xT1) = 14.7x6x(80+460)/(29.7x(32+460)) = 3.26 cu. ft.
66
96. What are two terms closely related to liquids?
Solution and suspension.
67
98. What is solution?
A homogeneous mixture (thoroughly mixed) of two or more substances, the composition of which may vary to a maximum limit, called the saturation point.
68
99. What is the saturation point?
A maximum limit of composition of two or more substances.
69
101. What is the hydrogen bond?
Water molecules are electrically attracted to each other because of their shape.
70
102. What is capillary action?
The liquid is raised or lowered as a result of the combined forces of adhesion, cohesion and surface-tension on the liquid.
71
103. What are three physical properties of pure water?
It is odorless, colorless, and tasteless.
72
104. Name a scale for measuring the acidity or alkalinity of water?
The pH scale read from 0 to14. 0.
73
105. Why is it important to know the pH value of water?
To determine if the water supply must be chemically treated to make it potable for human consumption. Water which is acidic is very corrosive.
74
106. Which water is acidic?
With a pH of 5 or lower.
75
107. A pH value of water suitable for use in piping systems and safe for human consumption?
7.0 - 10.5.
76
109. What causes deposits within pipelines and can cause them to close off completely?
Calcium.
77
110. How does calcium, magnesium sulfates, bicarbonate a and other hardness particles can be removed from hard water?
By installing a water softener that employ the principle of iron exchange to attract (capture) and remove calcium and other hardness particles from the water solution.
78
111. What is ion?
An atom or group of atoms or molecule with an unbalanced electrical charge as a result of having lost or gained one or more electrons.
79
112. How does water softener work?
Ion exchange is a reversible chemical reaction between a solid and a fluid (water) mixture by means of which ions may be interchanged.
80
113. What will be effected when the pressure of steam is changed?
1. Temperature of vaporization. 2. Sensible heat content ( heat content of the liquid). 3. Latent heat content ( latent heat of vaporization). 4. Total heat content (heat of the steam). 5. Volume. 6. Density.
81
114. How does steam expand?
Saturated expands 1700times and superheated steam expands more.
82
116. Heat content of saturated steam?
The sum of the sensible heat of the water, plus the latent heat of vaporization.
83
117. Types of saturated steam?
Dry-saturated steam or wet-saturated steam, depending on the amount of water contained in the form of mist. Superheated steam - saturated steam that receive additional heat At same pressure.
84
118. What is the condensing temperature of steam at 125 psig?
353*F.
85
119. What is the name of the number of Btu required to raise the temperature of one pound of water from 32*F to the boiling temperature?
Heat in water.
86
121. Compare the difference in the amount of latent heat liberated when one pound of steam is condensed at 35 psia and at 140 psia?
35 psia - 939.0 Btu 140 psia - 868.0 Btu Difference=939-868=71 Btu. More heat is liberated, 71.0 Btu, at 35 psia.
87
122. How many Btu are required to change one pound of water at 182*F into steam at 115 psia?
Total heat of steam at 115 psia - 1190 Btu Heat in water at 182*F - 150 Btu Heat required Btu = 1100-150=1040 Btu.
88
123. What is the volume of one pound of saturated steam at 70 psia?
6.0 cu. ft. per lb.
89
125. When will condensation of steam take place?
Only after the point of saturation has been reached because condensation entails loss of heat and consequently power.
90
126. When does saturated steam start to condense?
At once. The condensed water which covers the inside walls of pipes and steam cylinder causes a further loss of heat by radiation.
91
128. What is hydraulics?
It covers the subject of liquids in motion.
92
129. What is pneumatics?
The study of the mechanical properties of air and other gases (pressure, weight, expand ability, ect.
93
130. Give three examples of piping systems that have : 1 liquids only; 2 liquids and gases combined; 3 gases only?
1. Domestic hot and cold water, chilled water, heating hot water and sprinkler systems contain liquid water. 2. Sanitary wast and vent piping. 3. Air, ordinary natural gas, steam, vacuum, and oxygen piping.
94
132. What does the term fluid mean?
A substance that has the ability to flow (like water).
95
133. The relative thickness or thinness of a liquid that affect the rate at which a liquid flows?
Viscosity.
96
134. What is the weight of substance?
The measure of the force of gravity on a substance expressed in units such as pounds.
97
135. What is specific gravity?
The ratio of the density of a substance to the density of a standard of reference.
98
136. What can be used to measure specific gravity?
The hydrometer method.
99
137. What is the hydrometer?
A hollow glass tube which has been weighted with enough lead to make it float in an upright position with its stem out of the liquid. The specific weight of the liquid can be read on the scale etched on the side of the stem.
100
138. What is the weight of an equal volume of the standard, such as water or air?
Specific weight of a substance.
101
139. What are the standards for specific weight?
Water to compare the densities of all solids and liquids and air or hydrogen for gases.
102
140. Weight of water?
62.4 lb per cu ft or 0.0361 lb per cu in.
103
141. Specific weight of water, alcohol, Gasoline, ice, sea water?
``` Sea water - 1. 026, Water - 1, Ice - 0. 917, Alcohol - 0.79, Gasoline - 0.7. ```
104
142. Specific weights of mercury, lead, copper, brass, aluminum?
``` Mercury- 13.6, Lead - 11.38, Copper - 8.8, Brass - 8.39, Aluminum - 2.67. ```
105
143. Specific weights of steel pipe, wrought iron, cast iron?
Steel - 7.84, Wrought iron - 7.7, Cast iron - 7.2.
106
144. Specific weights of concrete, brick, cork?
Concrete - 2.2, Brick - 1.8, Cork - 0.24.
107
145. What is adhesion?
The property they causes dissimilar materials to be attracted to one another.
108
148. 3 way find specific weight of a substance?
SW = density of a substance /density of water = weight of substance / weight of equal volume of water = weight on air / loss of weight in water.
109
150. Where is capillary negligible?
In tubes greater than 1/4" diameter.
110
151. Give an example illustrating how some liquids are characterized by the phenomenon, of seemingly overcoming gravity, called capillarity?
Mercury is more cohesive than adhesive. If tube is inserted into a container of mercury, the liquid inside tube will actually be lower than the surrounding liquid.
111
162. The treatment of liquids at rest is known as?
Hydrostatics.
112
164. How do liquids exert pressure?
In all direction: downward, sidewise, and upward.
113
165. Name the pressure that is produced by the weight of the water below the surface of water which is exposed to atmospheric pressure?
Static head, static pressure, hydrostatic head or hydrostatic pressure.
114
166. Psia?
Pounds per square inch absolute.
115
168. Formula for the pressure exerted by a liquid?
``` It is directly proportional to its density: P=HxD, P-pressure, H-height, D-density. ```
116
170. Formula for pressure produce by water head?
P(psi) = H'x.433(psig/ft.hd.) = H"x.0361(lb/cu.in).
117
173. The Laws of liquid pressure?
1. It is directly proportional to the height of the liquid 2. Liquid pressure is directly proportional to the density of the liquid. 3. It is independent of the area or shape of the container, it is also independent of the direction.
118
175. Manometer?
Manometer. | Ma'nome^te^r.
119
176. Hot water temperature for commercial kitchen and sink for kids?
Commercial kitchen - 140*, | Children use - 110*.
120
177. Parts of metallic dial thermometer?
1. Bimetallic coil. 2. Pointer actuated by coil. 3. Scale (*C or *F).
121
178. The level of the water in the elevated tank is 50' above the top of a 6" horizontal water main. What is the total force acting on the bottom of the 6" vertical pipe connecting the tank to the water main if the tank is 12' in diameter and is 30' in length?
``` TF = AxP = (.7854xdxd)x(H'x.433psi/ft.hd.) = (.7854x6x6)x(50x.433) = 612.14, or TF = AxHxD = (.7854xdxd)x(50xD) = (.7854x.5x.5)x(50x62.4) = 612.61 lb. ```
122
179. Types of manometers?
1. An open manometer with a column of mercury or painted water. 2. A Bourdon tube gage.
123
180. Pascal's law?
Pressure applied anywhere Tia body of confined or enclosed fluid is transmitted with undiminished force in every direction. This pressure acts at right angles to every portion of the surface of the container, with equal force upon equal areas. Fluids comprise both liquids and gases.
124
186. If the 100' high 2" stack is converted from an open system toa closed system and has an additional 50 psig pressure added at the top, how will this affect the pressure in the rest of the stack? 2. When the system is pumped to a pressure of 50 psig at the bottom?
1. At the top of the stack, the pressure is 50 psig + 0 = 50 psig. At the bottom is 50 + 43.3 = 93.9 psig. 2. At the bottom of the stack we have 50 psig. At the top of stack pressure will be 50 - 43.3 = 6.7 psig.
125
187. What is the total thrust in lb on a 90* elbow on a 10" underground water main which will be tested at 200 psig? The thrust for a 10" 90* is 151 psig.
Total thrust = thrust x P = 151x200 = 30,000 lb.
126
189. Vaga?
A balance scale: 1. A rigid, uniformly dense beam. 2. Weighing pans. 3. Balance weights.
127
190. How may a barometer reading in inches of mercury be changed to pounds per square inch gage?
By multiplying by .491 the density of mercury.
128
193. Types of barometers?
1. Torricellian tube and bowl (mercury). | 2. Aneroid barometer.
129
195. Atmospheric pressure at sea level?
30" Hg.
130
197. Formula for absolute pressure?
``` Pa = Pg+Pat = Pg+Hg"x.491. Pa-absolute pressure. Pg-gage pressure. Pat-atmospheric pressure. Hg-pressure in inches of mercury. ```
131
203. How does absolute pressure differ from gage pressure?
Gage pressure is read starting from zero for atmospheric one absolute pressure is measured from zero for a perfect vacuum.
132
204. What is the abbreviation STP used for ?
To indicate standard temperature and pressure.
133
205. What are STP numbers?
Temperature- 32*F; | Pressure- 14.7 psia or 29.921" of mercury.
134
206. Types of tank used in closed hot water heating system?
1. Compression tank. | 2. Pre charged extension tank.
135
207. Where may non-potable pre charged water expansion tanks be installed?
In a tee or any other suitable tapping in the heating system.
136
208. Boyle's law?
The volume of a confined gas is inversely proportioned to the absolute pressure exerted on it, provided the temperature remains constant: V2/V1 = P1/P2.
137
209. How can Boyle's law be applied to an air chamber in a piping system?
You can determine how much air cushion remains in a 12" air chamber after it has been pressurized.
138
210. A 1" diameter air chamber 12" long is installed Ina cold water system. How much air space remains after a pressure of 60 psig has been applied to the system? Make calculation in cubic inches. The system is at sea level.
``` V2 = V1xP1/V1. V1 = AxL = .78x12 = 9.36; P2 = 60+14.7 = 74.7 psia; V2 = 9.36x14.7/74.7 = 1.84 cu.in. ```
139
212. What is often used to measure the draft in boilers?
A draft gage (the inclined manometer) with range of .10 to 1.0 in. W.C.
140
214. What is compressed air used for?
For the operation of automatic controls on heating, cooling, ventilation and air conditioning equipment.
141
215. Describe the operation of the pneumatic control system?
Compressed air operates the controlled devices, valves or damper operators on demand of the thermostat. Compressed air is provided by a compressor.
142
217. Give the brief description of the use of a vacuum pump in the pipe trades?
To evacuate refrigeration systems.
143
218. Types of vacuum pump?
1. The piston type. | 2. The sliding vane type.
144
219. Is there a rule of thumb for estimating remaining space after systems are pressurized for air chamber?
``` 15psig- 1/2 space remains; 30 - 1/3; 45 - 1/4; 60 - 1/5; 75 - 1/6 space remains. ```
145
232. How does the three pressure measurements approximately relate within 15% accuracy?
1/2 psig = 1" W.C. =1" mercury column.
146
234. Components of a dial type bourdon tube gage?
1. Flexible bent tube. 2. Link adjustment. 3. Pivot. 4. Segment gear. 5. Rotating gear. 6. Socket.
147
235. Hy does an object that is immersed in a liquid, seem to weigh less than it does on dry land?
Water exerts an upward pressure, or buoyant force, upon objects.
148
240. The law of flotation?
1. A body sinks in a fluid if the weight of the fluid it displaces is less than the weight of the body. 2. A submerged body remains in equilibrium, neither rising nor sinking, if the weight of the fluid it displaces exactly equals its own weight. 3. If a body, when submerged, displaces a weight of fluid greater than its own weight, it will float.
149
241. What is called buoyancy?
Upward support force equal to the weight of the liquid that has been displaced by the object.
150
242. What does the mechanism of stop/start control on a sump pump use?
Two weights at different levels in the sump.
151
243. How is water flow measured in the pipe trades?
``` The most common flow units are: 1. Gallons per minute (gpm); 2. Gallons per hour (gph). Other frequently used units are: 3. Cubic feet per minute (cfm); 4. Pound per hour (lb/hr). ```
152
245. What is the definition of velocity of flow?
The rate of motion per unit of time.
153
246. What is the pressure measured at any point while water is flowing which is read on a pressure gage installed in the piping?
The flow pressure?
154
247. What is bigger flow pressure or static?
Flow pressure is always less than the static due to friction loss.
155
249. What is meant by the term velocity head?
The decrease in the potential energy, or static head.
156
251. What are six factors which govern pressure drop caused by friction in a piping system?
1. Viscosity of fluid. 2. Length of pipe. 3. Velocity of flow. 4. Size and type of pipe. 5. Number and type of fittings and valves. 6. Number and degree of bends.
157
253. Where is laminar flow an important factor in a piping system?
It is especially desirable upstream from metering devices and pressure regulating valves.
158
254. What is used to provide the laminar flow necessary for accurate low measurement?
Straightening vanes: 1. One-piece. 2. Honeycomb.
159
255. Where is turbulent Dow desirable in piping?
In water heating devices as the mixing action of the fluid provides a better heat transfer. A fin tube baseboard heating element has the built-in obstruction which causes the desired turbulence.
160
256. How does a fluid act as it flows in a pipeline?
1. Laminar flow is in slightly slopping horizontal sewers or open drainage ditches, streams, or canals. 2. Turbulent flow occurs in most pressure piping such as domestic water lines or pumped liquid lines.
161
257. How does flow occur in piping system?
1. Unsteady flow - varies from a maximum at the time of greatest use to a minimum of no flow at all when no fixture are being used. 2. Steady flow - a constant rate of fluid flow (hot water recirculating line).
162
258. How can the volume of flow be determined?
By measuring the pressure on each side of the orifice , or the Venturi, the volume of flow can be determined from charts or tables which have been calculated by the use of a formula.
163
259. What are some methods which can be used to measure rate of velocity?
1. For water flowing in an open channel time the movement of an object being carried with the flow for a known distance. 2. By means of a propeller device. 3. The Pitot tube.
164
260. What is the average velocity In an ordinary pipeline?
About 80% of the maximum velocity.
165
261. The operation of a Pitot tube?
The impact of the water flowing into the opening in the submerged leg causes the water level in the upright leg to rise to a point where the head of water above the surface of the flowing stream exactly balances the pressure due to the impact ( velocity) of the water on the submerged leg.
166
262. How is the velocity determined from velocity head of a Pitot tube?
A chart gives values velocity of a fluid for each movement of velocity head.
167
264. Bernoulli's theorem?
In a piping system under steady flow, the sums of velocity head, the pressure head, and the elevation head are equal at each point within the pipe line.
168
265. What is the total head at the halfway point and at the bottom of the pipeline? W.H. is 100', a velocity head is10'.
``` 1. The total head at the half way point equals: Evaluation head - 50' Pressure head - 50' Velocity head - 10' -------- 110' 2. The total head at the bottom equals: EH-0" + PH-100' + VH-10' = 110'. ```
169
266. What is hydraulic ram?
A device is used to pump water from a source to a storage tank at a higher elevation without the use of electricity, gas or other energy.
170
267. Describe the operation of a hydraulic ram?
The supply water flows into the ram body through a drive pipe, and passes out through the impetus valve until the column attains sufficient speed to raise this valve to its seat. A small quantity of this water is forced through the check valve into the air chamber. After the impetus and check valves are close, the air , being then at a pressure greater than that due to the head in the dis charge line, forces this small quantity of water into the supply tank.
171
268. Extremes for difference between elevation and fall in a hydraulic ram system?
Min 6', max 12'.
172
269. How would journeymen working in the pipe trades make use of the principle that pressure varies inversely with velocity?
The discharge from a smaller nozzle at a very high velocity will cause the pressure at the nozzle outlet to be very low. By creating these below-atmospheric pressures at the Venturi tube, the fluid surrounding the nozzle will be sucked into the stream and mixed with the high-speed jet. This principle is applied in the jet pump and the common gas burner.
173
270. What is orifices use?
To measure flow and to regulate flow.
174
271. How is flow through orifices regulated?
The orifice which creates the high velocity jet is carefully sized so that gas, supplied at a constant pressure, will pass through it at a set rate, as required by the burner.
175
272. Parts of jet fitting for pumping well water?
1. Wide tube with low pressure well water. 2. Thin pipe with pumped water to jet nozzle. 3. Jet nozzle that causing pressures below atmospheric. 4. Venturi fitting where mixture of jet water and well water increase in pressure. 5. Wide pipe to storage tank and pump. 4.
176
273. Where is a flow regulator (regulating orifice) found?
In the cold water supply piping to a domestic hot water heater.
177
274. Why a flow regulator is sometimes found in the cold water supply piping to a domestic hot water heater?
The rate of flow is limited by the orifice in the flow regulator to the rate of recovery of the heater.
178
275. Typical piping arrangement of flow regulator and tempering valve?
1. Cold water supply valve. 2. Flow regulator. 3. Cross fitting to: A. Heat source; B. tempering valve; C. Drain valve. 4. (A) Heat source. 5. Hot water to tempering valve (has cold, hot and mix water connections). 6. Mix water to tempered hot water line to fixtures. 7. Hot water supply valve.
179
276. Ow does gas burner work?
High velocity gas jet producing low pressures (vacuum). Primary air enter burner. Mixture of primary air and gas increase pressure in Venturi tube and burn in outlet using secondary air.
180
277. How is flow through orifices measured?
Orifice plates are carefully manufactured, and through experimentation it has been dater mined exactly what the flow will be for each pressure differential.
181
278. What I a weir?
A dam in an open channel constructed so that the dam has an evenly shaped notch through which the water flows.
182
279. How are weirs used to measure flow?
It can readily be determined by measuring the depth of the water in this notch and consulting the flow data.
183
280. How are weirs used to regulate flow?
Flow through water-softening equipment is regulated by setting the float valve to maintain a certain depth of over-flow at the weir, to control the rate of back-washing.
184
282. What are some of the factors which cause resistance to flow in pipelines?
1. If you double the velocity of a fluid, the resistance will be increased by nearly four times. 2. A thick liquid, like heavy fuel oils can be heated to lower its viscosity and thus reduce its resistance to flow. 3. Roughness and smoothness of pipe walls. 4. The amount of corrosion and deposits depends on the composition of the fluid and action of the fluid on piping material.
185
283. What effect does the arrangement of pipe and fitting have on resistance to flow in a pipelines?
1. The longer the pipe the greater its resistance. 2. The sharper the bend, the greater the resistance. 3. Changes in pipe sizes made with bushings also cause more resistance to flow than do the gradually sloping changes of reducing fittings.
186
284. What does high velocity flow cause in a piping system?
1. Water hammer. 2. Increased friction loss. 3. Erosion.
187
285. How does high-velocity flow cause erosion in a piping system?
Fluids traveling at very high velocities wear away the material of the pipe walls.
188
286. Where is erosion by high velocities a particularly important?
In the thin-walled tubing of hot water heat exchanges.
189
287. A physical law inertia?
Matter resists change in its velocity.
190
288. What causes water hammer?
Inertia and the non-compressibility of liquids.
191
289. When does water hammer occur?
Water is traveling in a pipeline at high velocities and is suddenly halted by a quick-closing valve.
192
290. Factors contributing to water hammer?
1. Velocity. 2. Size of pipe. 3. Length of pipe. 4. High pressure.
193
291. How can water hammer be controlled or prevented?
1. Providing an air chamber adjacent to the point of sudden shut-off, where a cushion of air can absorb the shock of the water hammer. 2. Manufactured shock absorbers which mechanically prevent water hammer by means of a bellows, pistons, or diaphragm. They have the advantage of never becoming waterlogged.
194
292. What may be defined as any state of matter of a particular composition or make up?
A substance.
195
298. What is an element?
An element is any of more than 100 fundamental substances that consist of atoms of only one kind , and singly or in combination constitute all matter which can not be reduced by chemical means.
196
299. What is a compound?
A compound is a substance composed by uniting two or more simpler substances or similar elements by ordinary chemical action in definite pre portions.
197
302. What are the basic materials of which all substances are composed?
Elements.
198
307. List five elements commonly used in the piping industry, and give their chemical symbol?
1. Lead (Pb). 2. Copper (Cu). 3. Iron (Fe). 4. Tim (Sn). 5. Oxygen (O).
199
309. What is an atomic weight of the heaviest element known : ununoctium (Uuo)?
293.
200
312. What is the smallest particle of a substance which retains the properties of that substance and is composed of one or more atoms?
A molecule.
201
315. Because molecules take more space (increased movement) when they are heated, long runs of pipe have to be designed to withstand these forces. Expansion is one of the most powerful forces known. How is expansion controlled in piping systems?
By using either an expansion loop or a specially designed expansion fitting.
202
316. What temperature is water most dense at?
39*F.
203
319. What is absolute zero be calculated in *F?
-460*F.
204
330. List three terms that directly relate to a temperature change in a known substance?
1. Specific heat. 2. Sensible heat. 3. Latent heat.
205
333. What is a calorie?
The amount of heat required to raise the temperature of 1 gram (0.035 oz) of water 1* Celsius.
206
336. Is the specific heat of ice 1.5?
F. S=.53.
207
338. What are two terms closely related to liquids?
Solution and suspension.
208
339. What is meant by the term solution?
A homogeneous mixture (thoroughly mixed) of two or more substances, the composition of which may vary to a maximum limit, called the saturation point.
209
340. What causes suspension of particles on a liqui?
Solids not dissolved in a liquid.
210
341. What makes the water molecule very stable?
Hydrogen bond.
211
342. What are the physical properties of pure water?
It is odorless, colorless and tasteless.
212
343. A scale for measuring the acidity or alkalinity of water and refers tithe active hydrogen atoms of water?
The pH scale.
213
346. What is an ion?
An atom or group of atoms or molecule with an unbalanced electrical charge as a result of having lost or gained one pr more electrons.
214
347. What would happen if the pressure were suddenly released from an enclosed vessel of water at 300*F and 100 psig?
Flashing of steam.
215
348. What number of Btu will be involved when 50 lb of water at 32*F changes to ice at 32*F?
H=HltxW=144x50=7200 Btu.
216
349. How many Btu are required to change 20 gal of water at 212*F to steam at 212*F?
H=HltxW=970.44x20x8.33= 161.668.64 Btu.
217
350. Twenty cu.ft. of air is heated from 80* to180*F at a constant volume. What is the final pressure if the initial pressure is 10 psig?
P1/P2 = T1/T2 P2 = P1xT2/T1 = (20+14.7)x(180+460)/(80+460) = 41.13 psia =41.13-14.7 = 26.43 psig.
218
353. What is the word work when discussing machines?
The product of force times distance: FxD = W.
219
354. What is mean to do work upon the body?
A force acts upon a body and moves it.
220
356. What does the term power mean in a technical sense?
The rate of doing work.
221
358. What is unit of power?
Horsepower (hp).
222
359. What does horsepower mean?
Rate of work 550 ft.-lb per sec or 33,000 ft.-lb per min.
223
360. Formula for power?
P= TW/(550xT), P-horsepower (hp), TW-total work (ft.-lb), T-time (sec).
224
361. What horsepower engine is required to raise 2000 gallons of water per hour from a well 200' deep (disregarding efficiency and friction losses)?
``` P = TW/(33,000xT) = FxD/(33,000xT) = (2000x8.3)x200/ 33,000x60 = 1.676 hp. ```
225
362. List the six basic classifications of simple machines?
1. Lever. 2. Pulley. 3. Wheel and axle. 4. Inclined plane. 5. Wedge. 6. Screw.
226
363. What is the fixed point of a lever called?
The fulcrum.
227
364. List three classifications of levers?
1. 1st class - fulcrum between effort and resistance; 2. 2nd class - resistance between fulcrum and the effort; 3. 3d class - effort between resistance and fulcrum.
228
365. What is mechanical advantage?
M.A. Is the ratio of the force that performs work to the force which is applied to a machine, disregarding friction.
229
366. What is friction?
The resistance to motion between two bodies in contact.
230
367. How does friction affect machines?
It wears their moving parts and causes them to become impractical even though they may, theoretically, have a mechanical advantage.
231
368. How do we determine the mechanical advantage (M.A.) of a lever?
The length of the effort arm (EA) is divided by the length of the resistance arm (RA). M.A. = EA/RA.
232
370. One of the basic rules or lows of mechanics?
Work input is equal to work output (disregarding friction).
233
371. Why does the additional force gained by the lever is derived from additional motion at point EA?
Because the effort arm is times as long as the resistance arm, point EA moved times as far as point RA, and the work input is equaled the work output.
234
376. What does journey worker often uses to force pipe "home" instead CI pipe pulling tool?
A tunneling bar.
235
378. What is M.A. for a pulling tool for cast iron compression gasket bell and spigot pipe?
``` RA = 2"; Handle has 30"; M.A. = EA/RA =( 30"+2")/2" =16. ```
236
379. What is the M.A. of the shovel if from spud to lift arm are 3' and from that arm to fulcrum arm 2'?
M.A. = 2'/(2+3) = .4.
237
381. What is advantage of a third class lever?
A gain in speed or distance.
238
382. Examples of third class levers?
1. Broom. 2. Tweezers. 3. Ice cube tongs. 4. Human forearm. 5. Shovel.
239
383. How does statement: work input equals work output, disregarding friction, apply tithe three classes of levers?
The gain in force resulting in loss of distance and speed (2nd). The gain of speed and distance results in loss of force (3d). The first class lever can be adjusted.
240
384. How are pulleys used in the pipe trades?
Individually as well wheels, and in combination as block and tackle.
241
386. What is the rule for determining the M.A. of pulleys?
The mechanical advantage of a block and tackle is equal to the number of strands of rope supporting the movable block.
242
388. What is the total force acting on the top hook of pulley of 3 vertical blocks?
TF = WP+RF = 300+100 = 400 lb; TF-total force; WP-weight of pump; RF-force required to raise pump.
243
389. What is mechanical advantage gained by the pulley of 3 vertical blocks?
Not only reduces the force needed to raise the load, but also reduces the total force on the top hook.
244
391. What is the wheel and axle?
The wheel and axle utilizes circular motion to accomplish two basic functions. The first is to transmit force, and the second is to change speed.
245
392. Ratio of force, speed, wheel size of a simple wheel and axle machin?
``` F1xA1 = F2xA2; D1xV1 = D2xV2; C1xV1 = C2xV2; F-force; A-arm; D-diameter; V-velocity; C-circumference. ```
246
393. What is the formula for determining the M.A. Of the wheel and axle mechanism like hand brace?
M.A. = radius of wheel at handle/radius of axle at bit.
247
394. Types of the wheel and axle mechanisms?
1. Wheels are on separated axle: V-belt mechanism for speed changes. 2. Wheels are on the same axle for transmitting force and motion.
248
395. Transmitting force and motion through wheels and axles?
``` FxLA = RxRA: F-force; LA-lever arm; R-result; RA-radius of charge wheel. ```
249
396. Ratio for speed change of wheel with V-belt?
V1/V2=D1/D2=C1/C2; V-velocity; D-diameter of the 1 driver or 2 driven pulleys; C-circumference.
250
397. What is the function of most inclined planes?
Raise or lower heavy objects.
251
398. The formula for determining the M.A. of the inclined plane?
M.A. = L/H: L-length of plane; H-height of plane.
252
399. What is M.A. of ramp 4" heigh and 12' long?
M.A. = L/H = 12/4 = 3.
253
400. What are two uses of the wedge?
1. As cutting tools (chisels, ect.). | 2. To level equipment.
254
401. How is the M.A. of a wedge determined?
It is the ratio of its length to its thickness: M.A. = L/T: L-length, T-thickness.
255
402. Three uses of the screw?
1. Ditch jack. 2. Drill bit. 3. Pipe thread.
256
403. What is M.A. Of a screw?
The circumference divided by the pitch: M.A. = C/P: C-circumference; P-distance between threads.
257
405. Two basic classes of energy?
1. Potential. | 2. Kinetic.
258
406. What is the difference between potential energy and kinetic energy?
Potential energy is energy that is stored for future use. | Kinetic energy is energy related or pertaining to motion.
259
407. What is mechanical equivalent of heat?
778 ft.-lb = 1 Btu.
260
408. How does Joule apparatus for use in finding out how much work must be done to produce one Btu.?
The weights turn a set of paddles immersed in a known weight of water. The constant padding of the water warms it by friction.
261
409. How can heat energy be used to do work?
By combustion engines.
262
410. Types of combustion engines?
External and internal.
263
411. How does external combustion engines work?
Heat energy from the burning coal, oil, or nuclear reactor produces the steam and the steam pushes a piston or turns the blades of a turbine.
264
412. How does the internal combustion engine work?
The mixture of gasoline vapor and air is exploded in a thick-walled cylinder. The heat energy causes the gaseous products to expand and and push against the piston with great force.
265
413. What is high-pressure engine or a non-condensing engine?
By movement of the slide valve, steam is admitted alternately to the opposite ends of the cylinder, thus the piston is pushed back and forth because openings in the cylinder are connected alternately with the steam supply and the exhaust pipe by means of the sliding valve.
266
414. Describe the operation of a condensing engine (low-pressure engine)?
Stationary engines are fitted with a condenser, in which the spent steam is condensed by means of a spray of cold water. A partial vacuum is formed in the condenser and the back ward pressure of the air against the escaping steam is much reduce, possibly to only one pound per square inch.
267
415. How does steam turbine work?
High speed steam from nozzles strikes the rotating blades, is deflected and expends in the process. The stationary blades then catch the steam and direct it back against a second row of rotating blades.
268
416. What is formula for calculating the efficiency of a machine?
``` The ratio of the output energy to the input energy: E = OP/IP; E-efficiency; OP-output power; IP-input power. ```
269
417. Energy lost by machine?
1. Wasted heat. 2. The fuel is not completely consumed. 3. The hot gases going up the chimney. 4. Radiation. 5. Friction loss.
270
419. What is a metal?
A metal is an element that exhibits all or most of the following characteristics: 1. Solid at room temperature. 2. Opaque. 3. Conductor of heat and electricity. 4. Reflective when polished. 5. Expands when heated.
271
420. Symptoms of gradual mercury exposure?
Tremors, insomnia, memory loss, headaches, vision problems, irritability and nervousness.
272
421. How is mercury poisoning treated?
By administering chemicals that bond with the mercury and remove it from the body as waste?
273
422. What is an alloy?
A material or substance made up of two or more elements, at least one of which is a metal.
274
423. Alloyed materials which are used in the manufacture of pipe?
Brass, stainless steel, silicon iron.
275
424. Two types of synthetic materials?
1. Thermoplastic. | 2. Thermoset.
276
425. Difference between thermoplastic and thermoset materials?
Thermoplastic can be heated repeatedly and reshaped thermoset materials cannot beer formed even if subjected to melting.
277
426. Types of the synthetic materials used for piping?
Manufactured of a petrochemical base and are of the thermoplastic type.
278
427. What are some of the most common synthetic piping materials installed by journey workers?
``` Thermoplastic: ABS-acrylonitrile-butadiene-styrene; CPVC-chlorinated polyvinyl chloride; PE-polyethylene; PP-polypropylene; PVC-polyvinyl chloride; PVDF-polyvinylidene fluoride; Thermoset: FRP-fiberglass reinforced polyester. ```
279
428. A brief explanation of several characteristics pertaining to use the use of PVC and CPVC piping materials?
Have smooth, seamless interior walls and are light in weight. Inert to attack by most acid, alkalis, salt solutions, alcohols. Highly resilient, tough and durable products that have high tensile and high impact strength. Self extinguishing and will not support combustion. Non-toxic, odorless, and tasteless. Have a low thermal conductivity factor. Maintenance free.
280
429. Applications for PVC and CPVC piping?
Potable water, irrigation, chilled water, deionized water, chemical drainage, plating and chemical processing. They are not recommended for use in compressed air or gas service.
281
430. How is joining of PVC and CPVC materials accomplished?
By solvent cementing, threading or flanging.
282
430. What are the basic principles of solvent cementing PVC and CPVC pipe and fittings?
1. The joining surfaces must be softened and made semi-fluid. 2. Sufficient cement must be applied to fill the gap between pipe and fitting. 3. Assembly must be made while the surfaces are still wet and fluid. 4. Joint strength develops as the cement dries.
283
431. What is primer for PVC and CPVC?
Tetrahydrofuran (THF) and MEK may be used.
284
432. Use solvent cement?
PVC cement must be used with PVC pipe and fittings. CPVC with CPVC.
285
433. What type of applicator should be used to apply the primer and solvent cement to PVC and CPVC piping materials?
Daubers should only be used on pope2" and below. Brushes can be used on any diameter pipe, should have a width equal to at least 1/2 the diameter of the pipe. Rollers can be used on 4" and lager diameter pipe and should have a length equal to a at least 1/2 the diameter of the pipe.
286
434. List several factors which must be considered by journey worker when installing PVC and CPVC piping materials?
1. Hot weather: cementing operation should not be attempted where temperatures exceed 100*F. 2. Cold weather: primer and cements penetrate slower. 3. Set time: the time required before moving or handling the assembled joint (30 min for 1 1/2"-3" at 60*-100*F). 4. Cure time: the time is required before filling and pressurizing a system ( 2hr for 1 1/2-3" at 60-100*F up to 180 psig).
287
345. How are flanged systems limited for thermoplastic piping materials?
To 150 psig system pressure at 73*F. Flanges can be installed on the pipe by either solvent cementing or by threading.
288
436. Where should not threaded pipe and threaded fittings be used?
In high pressure systems or in systems where a leak could endanger personnel.
289
437. What are six rules which should be followed for threading plastic pipe?
1. Only pipe with a wall thickness of schedule 80 and above can be threaded. 2. Use pipe dies disowned for plastic pipe. 3. Use a strap type vise and wrench to hold the pipe or chain-type with a rubber sheet wrapped around the pipe. 4. Insert wooden plugs into the end of the pipe to be threaded. 5. Use a die that has a proper size guide to ensure it starts square. 6. Lubricate the cutting die.
290
438. How is polypropylene (PP) severely defeated?
Ultraviolet (UV) radiation and should be protected from direct exposure to the sun and other UV exposure.
291
439. Why do we use polyvinylidene fluoride (PVDF)?
It further extends the operating temperature/pressure range of thermoplastic piping.
292
440. Use of polyvinylidene fluoride (PVDF)?
It is not recommended for ketones , but is prefer in applications that demand high purity (electronic, pharmaceuticals, food and beverage processing.
293
441. How do you join fiberglass reinforced polyester (FRP)?
Hardener mixed with a polyester resin and applied to the joint and then reinforced with fiberglass.
294
442. What are four of the most common installation methods used to compensate for expansion and contraction of PVC and CPVC piping materials?
1. Expansion loops which consist of pipe and 90* elbows. 2. Piston type expansion joints. 3. Flexible bends. 4. Bellows and rubber expansion joints.
295
443. What must be done to ensure the satisfactory operation of a PVC or CPVC piping system?
1. Concentrated loads (valves, flanges, etc.) should be supported directly so as to eliminate high stress concentrations. 2. In systems where large fluctuations in temperature occur, allowance must be made for expansion and contraction. 3. Changes in direction should be supported as close as practical to the fitting. 4. Hangers should not restrict pipe expansion or contraction and a clamp type hanger should not deform the pipe when it has been tightened. 5. Hangers should provide as much bearing surface as possible. 6. Valves should be braced against operating torque. 7. PVC and CPVC lines must not be placed alongside steam or other high temperature pipe lines.
296
444. Why are metals usually specified for temperatures above 140*F and pressures above 65 psig instead synthetic piping materials such as PE and PVC?
PE and CPVC have flex distortion temperatures which are relatively close to 140*F at 65 psig and would likely fail if either the temperatures or pressures were to be increased.
297
445. What are the names of some fillers used in the manufacture of synthetic piping materials?
Silica-glass, graphite, clay, cotton flock, chopped rags, magnesium carbonate, magnesium silicate, mica, aluminum, sisal, wood flour, granulated cork, nut shell flour, perlite, calcium carbonate.
298
446. Name the raw material in which metal is contained?
Ore.
299
447. List the four most abundant metals found in nature?
1. Aluminum. 2. Iron. 3. Magnesium. 4. Titanium.
300
448. What are the four metals most commonly used in manufacturing pipe?
1. Steel. 2. Cast iron. 3. Copper. 4. Brass.
301
449. What are two general categories of piping materials?
1. Mechanical. | 2. Physical.
302
450. What are mechanical properties of piping materials?
1. Hardness. 2. Toughness. 3. Rate of expansion. 4. Endurance limit.
303
451. What are some of the physical properties of piping materials?
1. Electrical conductivity. 2. Heat conductivity. 3. Magnetism. 4. Density.
304
453. 4 the best conductor of heat?
1. Silver-100. 2. Copper-92. 3. Gold-70. 4. Aluminum-48. Glass 10-25, iron 16, steel 11.
305
454. What effect would the transfer of heat from water have in hydronic heating systems?
Conduction. The heat energy is transmitted by molecular vibration from molecule to molecule causing the surface temperature of radiation to increase.
306
457. Give some examples of the transfer of heat by convection?
1. Heating system convectors in room -natural convention. 2. Unit heater - mechanical convention. 3. A water tube boiler.
307
459. What gives off any heated object?
Radiant heat rays.
308
460. How does radiant panel heating system work?
The radiant rays from the pipe coils in the floor directly strike or are reflected like light rays to all room surfaces.
309
461. How can lead be welded?
Can not be arc-weded because low melting point but can be welded by lead burning.
310
462. What are the melting points of lead, copper, and iron?
1. Lead 621*F (327*C). 2. Copper 1,981*F (1,083*C). 3. Iron 2,795*F (1, 530*C).
311
466. Describe four basic methods used to control expansion in piping systems which operate at temperatures of 400*F or less?
1. Expansion loops. 2. Slip joints. 3. Flexible ball pipe joints. 4. Pack less expansion joints.
312
467. What is cold springing?
The technique is to install pipe with stress opposite that which would result when the pipe changes from its installed to its operating temperature.
313
468. The packing material of slip joints for expansion?
Teflon, graphite or other .
314
469. Use a slip joint for expansion?
Up to 250 psig, double accommodate travel of several feet, whereas single joints one foot. Should not be used in refrigerant piping.
315
470. What is pack less expansion joints?
Various types of bellows made of rubber, beaded hose over corrugated materials, corrugated copper, stainless steel and other metals.
316
471. What are some additional components normally required along with the use of the basic methods for controlling movement in piping systems?
1. Alignment guides. | 2. Anchors and restraints.
317
472. What are five specific examples of application for anchors, guides, restraints, stops and braces?
1. Anchors in a steam-distribution system to prevent overloading of stresses on the smaller branches. 2. Anchors and guides to actuate and align expansion joints. 3. Expansion loops to work with guides and anchors. 4. Restraints or fixed points in the vicinity of compressor equipment or quick-closing control valves. 5. Additional guiding or bracing to provide lateral structural stability to long , straight runs or sections of piping that are obviously weak in some plane.
318
473. How is that number or factor which shows the actual increase in unit length of a solid when it is heated one degree called?
Coefficient of linear expansion.
319
475. Formula for expansion length of a pipe?
``` EL = Lx(T2-T1)xCE: EL-expansion length; L-original length; T2-T1 - temperature change; CE-coefficient of expansion. ```
320
476. A section of mild steel pipe is 100' long at 30*F. How much will it expand when heated to 80*F? What will be its length at 80*F?
EL = Lx(T2-T1)xCE = 100x(80-30)x.0000063 = .0315' = .378"~3/8".
321
477. A 180*F domestic hot water piping system is installed in a building. The piping material used is copper. The building temperature at the time of installation is 49*F, and the length of straight pipe run is 100'. How much linear expansion will take place (in inches) when the system is started and the temperature of the pipe rises to the normal operating temperature of 180*F?
EL = Lx(T2-T1)xCE = 100x(180-49)x.0000092 = .12052' =1.45" = 1 1/2".
322
478. How much liner expansion would take place in 100' domestic hot water piping if system has 49*F before heating to 180*F if PVC piping maple rials were used?
EL = Lx(T2-T1)xCE = 100x(180-49)x.00003 = .393' = 4.72"~4 3/4".
323
479. Calculate the amount of expansion which can be expected of 300' of CPVC pipe installed at 50* and operated at 125*F?
EL = Lx(T2-T1)xCE = 300x(125-50)x.000038 = .855' = 10.26" ~ | 10 1/4".
324
480. What consideration must be made when installing PVC?
1. Expansion where waste water will reach temperatures above 180*F (dish washer wast). 2. It begin flex or distort at temperatures above 150*F.
325
481. How may the fact that solids have different coefficients of expansion be put to practical use in the case of the bimetal strip?
Bi-metal strip may be made by riveting or soldering together any two metals that have different coefficients of expansion. They will curve when heated, will straighten out again when cooled, or bend in the other direction if it is cooled greatly. They used in heating controls, such as certain types of steam traps, and electrical switches.
326
483. How is bimetal strip rate of expansion magnified for use as a controller within a room thermostat?
By shaping the bimetal strip in the form of a spiral. More metal is used and the movement is magnified.
327
485. Bimetal strips with the greater coefficient of expansion in the outside in a room thermostat?
1. Thermometer bimetal strip. | 2. Thermostat bimetal strip.
328
486. What are the components of a basic system of a pyrometer with a thermocouple?
A thermocouple attached to a connection or terminal head. It is connected by an extension wire to a pyrometer which incorporates an internal extension wire and the reference junction. Also contain components such as thermocouple protection tubes or wells, ceramic insulators on the thermocouple wires within protecting tubes, and various accessory fittings.
329
487. What is the purpose of the connection or terminal head?
Provide facilities for making positive electrical connections between the thermocouple and the extension wires. A means of attachment for a protecting tube and extension wire conduit. Must be completely weatherproof and other connection means.
330
488. How is an extension wire used in pyrometer systems?
Extends the thermocouple to the reference junction in a temperature measuring instrument.
331
492. What is adhesion?
The force of attraction between molecules of different kinds.
332
493. What is the tensile strength of a material?
The force needed to break a rod or wire of material having a cross-sectional area of one square inch or one square centimeter.
333
494. What is compressive strength?
Resistant to being pushed together.
334
495. Since mild steel is more resistant than cast iron to being pulled apart, is it also more resistant to being pushed together?
No. It's strength to withstand compression is almost twice that of mild steel.
335
496. What characteristic is shared by materials which are brittle?
They will fall (crack or break) suddenly without previously showing signs of fault or deformity.
336
497. What is ductility?
The ability of a metal to stretch and become deformed without breaking or cracking.
337
499. What is malleability?
Property of a metal that allows it to be hammered or rolled into sheets without causing separation of the molecules.
338
500. What is elasticity?
The ability of matter to regain its original form after it has been deformed by some force.
339
501. When does law hold true? Law: the amount of distortion produced in a body when a force acts upon it is directly proportional to the magnitude of the force.
Only while the body remains within its elastic limit.
340
503. Why does the water service entering a building illustrates a situation where the shear strength of a material can be important to a journeyworker?
Most codes call for inserting a supporting arch or steel sleeve in the construction where the water service for the building passes through the outside wall. This protection helps prevent the service from being sheared off. Yet if the building settles, the service can still be subjected to a shearing force.
341
504. Why does the solder in the joint shear when a soldered joint on domestic hot water or hydronic hot water heating pipeline blows apart?
If you inspect the fitting and the copper tube taken from a sheared joint, you will find both the cup of the fitting and the outside of the tube still have solder adhering to them. That mean that the solder sheared from itself, not from the copper.
342
505. List five properties which are usually contained by ferrous metals?
1. They are ductile. 2. They are malleable accept cast iron. 3. They have high tensile strength. 4. They conduct heat and electricity. 5. They can be magnetized.
343
506. Ferrous and nonferrous metals?
``` Ferrous: 1. Steel. 2. Wrought iron. 3. Cast iron. Nonferrous: 1. Copper (pure metal). 2. Stainless steel. ```
344
508. What is alloying?
The mixing of metals.
345
509. What is silicon iron?
Fe-84%, Si-14%, C-0.8%,Mn-0.4%.
346
510. What is wrought iron?
An alloy of iron and iron silicate (slag). It has more sacrilege and corrosion resistant than iron.
347
511. What is metallurgists termed to describe the transformation phases (melting, freezing, etc.) of an alloy?
A constitutional or equilibrium diagram.
348
512. What is the melting point of 50-50 solder?
It begins to melt at 361*F and completely liquefies at 420*F.
349
513. How do you call temperature at which alloy begins to melt and temperature at which it completely liquefies?
A pasty range.
350
515. List seven classifications of iron and steel, from the least expensive to the most expensive?
1. Pig iron. 2. Cast iron. 3. Wrought iron. 4. Carbon steel. 5. Alloy steel. 6. High-alloy steel. 7. Tool steel.
351
516. What is mild steel?
Low-carbon steel.
352
517. List five mechanical properties of mild steel pipe?
1. High ductility - can be stretched. 2. Malleability - can be bent. 3. Not brittle - resists cracking. 4. High tensile strength. 5. Medium compressive strength.
353
518. The general classes of cast iron?
1. Gray. 2. Alloy. 3. White.
354
519. List five mechanical properties of gray cast iron?
1. Low ductility - resists stretching. 2. Not malleable - cannot be bent. 3. Brittle - cracks easily. 4. Low tensile strength - pulls apart. 5. High compressive strength -resists crushing.
355
520. How is malleable cast iron produced?
From white cast iron. It is subjected to temperatures within a range of 1,500*F to 1,650*F for several days in an annealing process and the following cooling process.
356
521. What disadvantage of high carbon steel prevents its use as a common piping material?
The more carbon a steel contains, the tougher it is, and as a result the more difficult it is to join.
357
522. What are commonly referred to as stainless steels?
Chromium/nickel steels. The most prominent of the group contains 18% chromium and 8% nickel.
358
524. What is brass?
Zinc (1%-50%) is added to copper to make at least 15 commercial brasses.
359
526. What alloying elements are added to copper to make bronze?
The most commonly tin, silicon, aluminum, and beryllium.
360
527. What happened to a metal that has been annealed?
It has been softened.
361
528. Difference in annealing steel and copper?
1. Mild steel must be heated to around 1,600*F and held at that temperature for a specified time. Then the temperature is lowered very slowly under controlled conditions. 2. Copper must be heated to a temperature within a range of 700*F to 1,200*F. It will remain annealed, regardless of whether the temperature is reduced slowly or quickly.
362
529. How can copper be hardened?
After annealing process has taken place, but only by work hardening (hammering or drawing).
363
530. How can mild steel be hardened?
By heating the metal to approximately 1,600*F and then quenching it in liquid.
364
531. What is meant by the term tempering?
A process on which already hardened steel is reheated to some point below the hardening temperature and allied to cool in the air.
365
532. What is reclaiming attack of corrosion?
It. Is nature's way of reclaiming metals that were acquired and refined from the earth's ores.
366
534. What are three basic kinds of corrosion?
1. Chemical. 2. Physical. 3. Electrochemical.
367
535. What is chemical corrosion?
Produced by the reaction of metals when they come in contact with an acid.
368
536. What is physical corrosion or corrosion-erosion?
For example the presence of suspended particles in a moving stream of water accelerates the abrasive action which increases the rate of corrosion.
369
527.. What are three other causes of high velocities in piping systems?
1. The under sizing of the piping for a given flow rate. 2. The cavitation: the rapid collapsing of air bubbles, usually occur on pumps when the suction piping is too small or the discharge head is not sufficiently high. 3. The flashing of a hot liquid into a vapor as pressure is suddenly reduced.
370
528. How is electrochemical corrosion defined?
Chemical reaction involving oxidation, reduction, and transfer of electrons.
371
529. How is the rate of electrochemical corrosion expressed?
In pound per ampere year.
372
530. Where is electrochemical corrosion occurs?
At the negative electrode (anode).
373
531. What are called electrodes?
The amides and cathodes involved in a corrosion reaction.
374
532. What is anode?
That portion of a metal surface which is corroded, and it is the location where current leaves the metal to enter the solution (electrolyte).
375
534. Types of corrosion damage?
1. Uniform attack. 2. Pitting corrosion. 3. Impingement attack. 4. Stress corrosion cracking. 5. Selective attack. 6. Inter granular corrosion. 7. Corrosion by differential environmental condition. 8. Oxidation. 9. Localized corrosion. 10. Deposit attack.
376
535. What is uniform attack?
General wasting away of metal in contact with an electrolyte.
377
536. What is pitting corrosion?
The localized breakdown of a protective film or layer of corrosion products form anoxic areas and cathodic areas form at the unbroken portion of the film.
378
537. What is impingement attack?
The result of turbulent fluid with high velocity breaking through protective films or corrosion films on a metal surface.
379
539. What is selective attack?
The corrosive destruction of one element of an alloy.
380
541. Contributing factors of corrosion by differential environmental conditions of underground piping systems?
Variations in moisture content, availability of oxygen, and change in soil resistivity.
381
542. What is oxidation?
When iron combines with water and oxygen in the atmosphere, it produces a red-brown iron oxide (rust), an insoluble corrosion product known as ferric hydroxide.
382
543. List three examples of oxidation?
1. A red-brown rust on iron. 2. White specks on aluminum. 3. The greenish coating that accumulates on corroding copper.
383
544. Why does the special low-alloy steel permit the erection of steel structures without using paints or coatings?
A surface layer of iron oxide form a protective film which separates the underlying metal from its environment.
384
545. What is localized corrosion?
Selective attack on a metal by corrosion at small special areas or zones on a metal surface in contact with an environment (water, acids or alkalis).
385
546. How do local-action cells affect a buried metal pipeline?
As long as the metal remains dry, little corrosion takes place. Where the metal is exposed to or contain a solution that can conduct electricity local-action cells may be responsible for the corrosion.
386
547. What are the three main types of cells that take part in the electrochemical corrosion reaction?
1. Different temperature cells. 2. Concentration cells. 3. Dissimilar electrode cells.
387
548. What are different temperature cells?
Components of these cells are electrodes of the same metal, each of which is at a different temperature, immersed in an electrolyte of the same composition.
388
549. Where does different temperature cells occur?
In heat exchangers, boilers, immersion heaters, and similar equipment.
389
550. What are concentration cells?
1. Electrodes of the same metal are exposed to a concentrated solution, the other to a diluted solution. 2. There are differential aeration cells: the electrolyte around one electrode being thoroughly aerated (cathode), and the other deaerated (anode).
390
551. What is dissimilar electrode cells?
The anode is the more active on the galvanic electromotive force series and the cathode the more noble metal immersed in an electrolyte making up the cell.
391
553. How can a temperature cell be created?
The hot pipe near the heat source is the anode, the cooler pipe down the line is the cathode, the soil is the electrolyte, and the pipe itself is the connecting circuit.
392
554. How does temperature increase corrosion rates in domestic hot water systems?
It double for each 10*F rise above 140*F water temperature.
393
555. Why will hot water lines corrode before cold one?
Usually the rate at which a material corrodes increases as the temperature increases.
394
556. How can an oxygen concentration cell cause corrosion on a buried pipeline?
The space around the sides and on the top of a pipe is relatively loose back fill which has been replaced in the trench. Because backfill is more permeable to oxygen diffusing down from the surface , a cell is formed. The anode is the bottom surface of the pipe and the remainder of the surface of the pipe becomes the cathode. This is why the most corrosive attack on pipelines is on the bottom quarter of the pipe.
395
557. What is extremely important to corrosion rates?
The homogeneity of a metal and of the electrolyte. Non-homogeneous metals or electrolytes cause local attack or pitting.
396
559. How does bacteria effect corrosion?
Microorganisms can cause sever corrosion of buried piping in both aerated and unaerated soils.
397
560. What do not many codes allow underground piping to be run through?
Cinder filled areas or buried within cinder concrete.
398
562. How can the corrosion of metal be protected by the formation of film on the surface?
Thin, hard, dense, tightly adherent films afford protection whereas thick, porous, loose films allow corrosion to proceed without providing any protection .
399
563. What is a galvanic couple?
A pair of dissimilar metals, capable of acting together as an electrical source when brought in contact with an electrolyte.
400
564. What is the definition of a galvanic cell?
Two electrodes and an electrolyte capable of producing electricity by chemical action.
401
565. Basic parts of dry cell battery?
1. Zinc container with negative pole. 2. Carbon electrode with positive pole. 3. Chemicals to form an electrolyte. 4. Seal.
402
566. What action takes place if the terminals on a flashlight battery are connected?
They form a galvanic couple of both elements. Because of their distance apart on the galvanic scale , they exhibit high rates of corrosion which produces a high rate of electric current.
403
567. What is a practical scale to determine corrosion rate?
The galvanic series.
404
568. Why is the rate of corrosion of a piping system connected together with two dissimilar metals, or surrounded by two different soils, determined by the relative potential between the two metals and by the resistance of the electrolyte (soil)?
When any two buried dissimilar metals are connected together so that a path is provided for electric current to flow, one of the metals will tend to corrode.
405
569. Why are gate valves which have a cast iron body with bronze gates and spindles used even thought the bronze trim and the cast-iron body indicate some tendency to form a galvanic couple?
Because bronze and cast iron are relatively close in the galvanic series and because of their natural resistance to corrosion, the rate of corrosion in normal usage will be very slight.
406
570. List five other examples of corrosion of underground piping?
1. When connecting old cast iron pipe to new steel pipe, the new steel pipe is more active in the galvanic series than old cast iron pipe. 2. A steel or cast iron pipe acting as an anode to a copper or brass service branch. 3. A cast iron or steel pipe with one copper or brass and one galvanized steel service branch. 4. When iron pipe is nicked or threaded, that areas become bright metal and, therefore, are anodes and will corrode. 5. If one area of the surface of the pipe has more carbon, the area with the most iron will become an anode to the area where the carbon is greater.
407
572. Describe the sequence of conventional current flow associated with corrosion on an underground pipeline with electrolytes of different electrical charges?
1. Current flows through the electrolyte from the anode to the cathode. 2. Corrosion occurs wherever current leaves the metal and enters the electrolyte. The point where the current leaves is called the anode. 3. Current is picked up at the cathode. 4. The conventional flow of current travels back to the anode from the cathode through the pipeline to complete the circuit.
408
573. List four conditions which cause corrosion of metal pipelines because of dissimilar soil?
1. Corrosion caused by cinders can take place in two ways: by direct contact or from the sulfuric acid leaking from it. 2. The soil above the pipe is loose and well-aerated, while the bottom of the pipe is resisting on undos turned, moist soil. 3. A pipeline which extended through two different soil: the corrosive - clay, and the less corrosive - sand or loam. 4. Soils of different moisture content. The moist soil - wet marsh or swamp ground and the drier - higher ground or sand.
409
574. What is deposit attack?
Depositing corrosion is another form of pitting corrosion which can occur in a liquid environment when a more cathodic metal is plated out of solution onto a metal surface. Particles of metallic copper from pipe will plate out on the surface of a galvanized or aluminum vessel and stimulate pitting.
410
575. Why does stray current corrosion can occur any time a pipeline is laid in the vicinity of an electric railway system, direct current generator, or manufacturing plant?
Pipelines have lower resistance to current flow. The area where current enters the pipe may show little or no corrosion, but the area where current leaves the pipe may be heavily corroded.
411
576. List three troublesome situations that affect the corrosion resistance of copper tubing?
1. Aggressive well water which causes pitting. 2. Systems design or installation practices which result on excessive water velocity causing erosion-corrosion or impingement attack. 3. Pitting caused by residual aggressive flux left inside the copper tube after installation. Excess flux polymerize if joints have been overheated.
412
577. What alloys are often used in constructing hot water storage tanks?
Copper silicon alloys, copper bearing steels.
413
578. What alloys are often used in heat exchangers and in moving parts of valves and controls?
Bronze and other copper alloys.
414
580. What are three corrosion resistant materials commonly used in the pipe trades?
1. Cast iron and lead protected by coating of corrosion products. 2. Brass,aluminum, stainless steel have natural resistance. 3. Nonmetallic piping materials such as terra cotta, cement, bituminous fiber, plastic, and glass.
415
581. Why is cathodic protection an effective method to control corrosion of buried or immersed metallic structures such as water lines and tanks?
It make them the cathode and apply direct current to the electrolyte from an anode source.
416
582. The two proven methods of applying cathodic protection to a buried pipeline and underground storage tank?
1. With galvanic anodes( usually magnesium or zinc). | 2. Impressed current systems.
417
583. How does the impressed current system work?
An AC-DC rectifier provide current to relatively inert anodes in a ground bed (scrap metal or carbon rods) and can be adjusted to provide the necessary voltage to drive the required current to the structure surfaces.
418
584. Where are sacrificial or galvanic anodes used most advantageously?
On coated pipelines in low resistance soil where current requirements are low.
419
585. What are five advantages of galvanic anodes?
1. Relatively low installation cost. 2. Do not require an external power source. 3. Low maintenance requirements. 4. Usually do not cause adverse (stray current) effects. 5. Can be installed with the pipe.
420
586. Three disadvantages of galvanic anodes are?
1. Driving voltage is low (approximately 0.75 volts). 2. Current output limited by soil resistance. 3. Not applicable for large current requirements.
421
587. Where are impressed current systems used ?
For structures having large current requirements such as bare pipe, tank farms, large diameter cross country pipelines, cast iron water lines and many offshore facilities.
422
588. Describe the operation of the impressed current system of cathodic protection?
Graphite, platinum or high silicon iron anodes connected to an AC-DC rectifier produced several hundred amperes current, which in turn is wired to the structure being protected.
423
589. What is a rectifier for?
Changes AC current to DC.
424
590. Five advantages of the impressed current system?
1. Large current output. 2. Voltage adjustment over a wide range. 3. Can be used with high soil resistance environment. 4. Can protect uncoated structures. 5. Can be used to protect large pipelines.
425
591. Some dis advantages of the impressed current system?
1. Higher installation and maintenance cost. 2. Power costs. 3. Can cause adverse (stray current) effects.
426
592. What is stray current corrosion?
Electrical current may be picked up on a pipeline or structure that is not part of the protected system and travel through the electrolyte back to the system causing sever corrosion at the point of discharge.
427
593. What can produce stay electrical currents that can cause buried piping system to corrode?
1. Cathodic protection by the impressed current method. | 2. Grounding of welding machines and generators to piping connected to buried piping system.
428
594. How can piping systems be protected against stray electrical currents?
1. Bonding the pipe system to the source. 2. Cathodic protection. 3. Insulating couplings in the pipelines. 4. Coatings.
429
596. What are three other methods of corrosion control that can be utilized with cathodic protection on piping systems?
1. Coating that are non-conductors of electricity. 2. Dielectric insulation. 3. Test stations. They are used also to make bonds or connections between structures to eliminate stray current effects.
430
597. What is a dielectric fitting?
An insulator that contains insulating materials (plastic, Teflon, red fiber insulation, etc.), which is placed between dissimilar or similar metals to help prevent an electrical circuit from being formed.
431
598. Difference between dielectric flange unions copper from steel and steel from steel?
Copper from steel has 5 bolts steel one 4.
432
599. What special consideration should be given when installing instantaneous or tankless hot water heaters?
It should be provided with the necessary connections for back washing to remove sediment that tends to accumulate.
433
600. Parts of connections for back washing of instantaneous or tankless hot water heaters?
1. Damp valve on T between WH and inlet valve. 2. Inlet valve on cold water supply line after by-pass T. 3. Outlet valve on the hot water line between by pass T and temperature control valve. 4. By-pass valve between cold and hot water line.
434
601. List seven installation procedures which should be followed when installing insulation fittings?
1. Do not subject to temperatures and pressures above the maximum rating. 2. Do not apply torch heat to the assembled fitting. 3. Do not over tighten the fitting. 4. It can not serve as expansion fittings. 5. Should not be used underground. 6. Should not be used on gasoline and similar hydrocarbon piping systems. 7. Coordinate with the manufacturer's specifications for special applications.
435
602. How is the solution, be it liquid or vapor, forming the electrolyte called?
The corrodent.
436
603. What is corrodent?
The fluid within a piping system or in the atmosphere or ground surrounding a pipe.
437
604. What term is for a substance when added to an environment to decrease the rate of attack on a metal used?
Corrosion inhibitor.
438
605. How can inhibitors be beneficial in combatting corrosion of a metal pipeline?
1. Some retard corrosion by absorption to form a thin, invisible film only a few molecules thick. 2. Form visible bulky precipitates which coat the metal and protect it from attack. 3. Cause the metal to corrode in such way that a combination of absorption and corrosion product forms a passive layer.
439
606. List six reason for using inhibitors to prevent corrosion of piping systems?
1. To extend the life of equipment. 2. To prevent shutdowns. 3. To prevent accidents resulting from brittle (or catastrophic) failures. 4. To avoid product contamination. 5. To prevent loss of heat transfer. 6. To preserve appearance.
440
607. Where are inhibitors used?
1. Boiler feed water must be treated to maintain proper pH control, dissolved solid levels, and oxygen content. 2. Condensate requires treatment to control corrosion by oxygen and carbon dioxide. 3. Brine refrigerants and cooling water in closed loop circulating systems.
441
608. What are two important factors to be considered when using inhibitors to prevent corrosion of piping systems?
1. A testing program must be established to ensure that proper additive levels are maintained. 2. Safety precautions must be observed to cover personnel protection, environmental protection, and equipment operation protection.
442
609. What provisions should be made for possible future treatment of the water supply?
If there is any possibility that the water supply is , or may become corrosive or scale-forming, by-pass valve between two capped T with insulation valves should be installed. Space 5'x5'x7' should be provided to permit convenient installation of appropriate water treatment equipment for the future.
443
610. What are other types of protective coatings and linings that can used on piping systems and related equipment?
1. Glass lining for water tanks. 2. Cement linings for cast-iron water pipe, and in storage tanks. 3. Ceramic linings in smoke stacks. 4. Plastic linings in tanks and fittings. 5. Coatings of porcelain enamel on cast-iron and steel on plumbing fixtures.
444
611. How do you make coating on piping systems and related equipment?
Coatings of paints or mastics are brushed or sprayed on the articles to be protected. There are coatings of tapes and dips.
445
612. Three safety precautions that should be taken by journeyworkers when it is necessary for them to apply coatings at the job site?
1. Coatings incorporating flammable or explosive materials should not be used in the vicinity of open fllames, sparks, or energized electrical equipment. 2. When used in confined spaces, solvents and solvent vapor concentration should be kept below the explosive limit, and below the acceptable toxicity level. Ventilation of confined spaces must be continuous during the period of time work is performed and for several hours afterward. The use of safety approved explosion proof electrical power tools and equipment is mandatory. 3. Solvent vapor must be removed from tanks by suction because many vapors are heavier than air.
446
613. Where should test connections for corrosion control anodes, test specimens or readily removed test sections of pipe be placed?
At locations where there is appreciable flow which is representative of the flow conditions in the piping installation(s) serving the building.
447
614. Why are higher priced metals applied to a cheaper metal as a thin coating to provide the base metal with the corrosion resistant qualities of the coating metal?
1. It is highly corrosion resistant in the open atmosphere. | 2. It tends to act as a sacrificial anode when a coating becomes damaged and leaves the base metal exposed.
448
615. What are corrosion resistant metallic coatings?
1. Zinc is the most common metallic coating used in the piping trades. 2. Tin is used to coat nearly all of the light-weight steel for food cans. 3. Cadmium is a common coating of bolts and other fasteners. 4. Lead is used to line acid tanks and to coat sheet copper flashing material. 5. Aluminum is used to protect steel products at high temperatures.
449
616. What is another means of protecting a piping installation (galvanic, inhibition, coating) against corrosion?
Natural protection for sipping installation is afforded when the base materials selected are such that, under normal conditions of usage, offer natural resistance to corrosion.
450
617. What are five installation practices which can be used to eliminate or minimize corrosion attack?
1. Provide dielectric insulation between dissimilar metals. 2. Avoid damage to areas on the surface of materials. 3. Do not use excessive welding heat. Large grain sizes caused by over heating a metal can result in accelerated corrosion which changes the physical properties of the metal. 4. Crevices inside piping should be avoided. 5. Condensation of moisture from the air on cold metal surface can cause extensive damage. Piping should be insulated.
451
618. How can some of the rules of good craftsmanship be summarized with regard to piping systems installed by journeyworkers in their effort to combat the problem of corrosion?
1. Maintain a good protective coating on metals which tend to corrode easily. 2. Avoid metal-to-metal contact between dissimilar metals. 3. Follow carefully the designer's requirements for the use of corrosion resistant materials. 4. Don't shortcut the design of a cathodic protection system; one missing or defective component can destroy the protection of the entire system.
452
T3. What is the melting point of copper?
1983*F or 1084*F.
453
T13. What three terms related to temperature change?
Specific heat, sensible heat, latent heat.
454
T19. What is a solution?
When solid is dissolved in liquid.
455
T20. What is a suspension?
It is mixture of substance that can be separated mechanically.
456
``` T39. A 5 foot cube weighing 3900 pounds is placed in water, will it: A. Float on top. B. Float half submerged. C. Float 3/4 submerged. D. Sink? ```
Ww = VwxD = LxSxHxD = 5x5x5x62.4 ~ 7,800 ~ 2 of 3,900. | B. Float half submerged.
457
G1. Abrasion resistance?
The measure of a material's ability to withstand erosion when subjected to rubbing, scraping, wearing, scouring, etc., conditions.
458
G4. Acetal plastics?
A group of plastic made from resins which have been obtained by heating aldehydes or ketones with alcohols.
459
G5. Acid?
A substance which dissolves in water with the formation of hydrogen ions.
460
G6. Acidity?
The quality of a solution (water) becoming acid.
461
G7. Active?
A state in which a metal tends to corrode.
462
G8. Active metal?
A metal ready to corrode, or being corroded.
463
G9. Adhesion?
The property that causes dissimilar metals to be attracted to each other. The force of attraction between molecules of different kinds (glue to wood, solder to copper).
464
G10. Adhesive?
A substance capable of holding materials together by surface attachment.
465
G11. Aeration cell?
An oxygen concentration cell an electrolytic cell resulting from differences in dissolved oxygen at two points.
466
G12. Aging?
The effect on materials exposed to an environment for a period of time. Also, the act of exposing materials to an environment for a period of time.
467
G13. Alkalies?
Compounds capable of neutralizing acids.
468
G14. Alloy?
A mixture of two or more metals or a metal and something else.
469
G16. Ampere?
Current produced by one volt acting through a resistance of one ohm.
470
G17. Anion?
A negatively charged ion of an electrolyte which migrates toward the anode under the influence of a potential gradient.
471
G18. Anneal?
To heat and then cool slowly so as to prevent brittleness. To strengthen and temper.
472
G20. Antimony (Sb)?
One of the metal elements. A hard, rare, silvery-white, crystalline metal used primary to alloy with metals to harden them and add resistance to corrosion.
473
G21. Antioxidant?
A substance added to a plastic compound to retard degradation due to contact with air (oxygen).
474
G23. Archimede's principle?
A body immersed in a fluid loses as much weight as the weight of the fluid it displaces.
475
G25. Atom?
The smallest particle of an element that can exist either alone or in combination with other elements.
476
G27. Beam loading?
The process of applying a specified force (load) to a piece of pipe which is supported at two points. It is usually expressed in pounds per distance between the centers of the supports.
477
G29. Bernoulli's theorem?
In a system under steady flow the sums of velocity head, pressure head, and elevation head are equal at each point within the pipe line.
478
G30. Beryllium (Be)?
One of the metal elements. A hard rare metal used primary to alloy with other metals such as copper and nickel.
479
G31. Blister?
An under sortable air or gas filled bubble (bump) on the surface of a plastic part.
480
G32. Calendering?
A proves for making thin sheets of plastic or rubber in which a heated plastic or rubber compound is squeezed between heavy rollers.
481
G33. Calorie?
The amount of heat required to rise the temperature of 1 gram (.035 oz) of water 1 degree Celsius.
482
G34. Capillary action?
The action whereby a liquid rises vertically in a small space or tube through adhesion and cohesion such as solder rising vertically Ina soldered joint.
483
G36. Cast iron?
An alloy of iron and some other metal or substance, usually graphite, to form gray cast iron. Cast iron is hard, brittle , not malleable, with high compressive strength, low ductility, and low tensile strength. Often used in the manufacture of pipe fittings.
484
G38. Bond?
To attach by use of an adhesive.
485
G39. Bourdon tube pressure gage?
A gage employing the use of a small diameter curved tube which is linked to gears and an indicating needle. An instrument used to measure pressure. Pressure tends to flattens curved tube which is attached to a pointer.
486
G40. Boyle's law?
The volume of a confined gas is inversely proportional to the absolute pressure exerted on it, provided the temperature remains unchanged.
487
G41. Buoyancy?
The upward for e which any liquid exerts upon a body submerged in it. An object will float if the buoyant force of the liquid is greater than the weight of the object itself.
488
G42. Burst strength?
The amount of internal pressure a piece of pipe or a fitting will hold before breaking.
489
G46. Bronze?
A commonly used alloy with excellent resistance to corrosion formed of various mixture of copper, tin, silicon, aluminum and beryllium.
490
G47. Cathodic protection?
The control of the electrolytic corrosion of an underground or underwater metallic structure by the application of an electric current in such a way that the structure is made to act as the cathode instead of the anode of an electrolytic cell. The use of materials and liquid to cause electricity to flow to prevent corrosion.
491
G48. Cavitation?
Formation and sudden collapse of vapor bubbles in a liquid usually resulting from low pressures, momentary high pressure can mechanically destroy a portion of a surface on which the bubbles collapse.
492
G49. Cavitation corrosion?
Corrosion damage resulting from cavitation and corrosion; metal corrodes, pressure develops from collapse of cavity and removes corrosion product, exposing bare metal to repeated corrosion.
493
G50. Cavitation damage?
Deterioration of a surface caused by cavitation (sudden formation and collapse of cavities in a liquid).
494
G52. Cellulose acetate?
A type of resin made from the reaction of acetic acid or acetic anhydride with a cellulose base (cotton and/or wood pulp).
495
G54. Change of state?
All pure substances will undergo changes instate due to a transfer of heat or a change in pressure.
496
G55. Charlie's law?
The absolute pressure exerted by a gas is in direct proportion to the absolute temperature, when the volume is held constant.
497
G56. Chemical change?
A change which causes a new substance or substances with different chemical composition to be formed. (Rust formation on the inside wall of a steam pipe in which air has been allowed to accumulate.)
498
G57.chemical resistance?
The ability of a plastic to withstand the effects of chemicals at various concentrations and temperatures.
499
G58. Chlorinated polyvinyl chloride?
A thermoplastic composed primarily of PVC but with additional chlorine added during processing so as to withstand pressures and higher temperatures.
500
G59. Chromium (Cr)?
A very hard metal element with excellent resistance to corrosion used to plate metals and to alloy with other metals.
501
G60. Coefficient of expansion?
The rate of increase in the unit dimension of a body as its temperature is rises one degreeFahrenheit.
502
G62. Cold flow?
A change in the shape or the dimension of a plastic part when subjected to a load (weight or pressure) at room temperature.
503
G63. Comfort.
The condition in which the body feels neither too warm nor too cool.
504
G64. Compound?
A substance composed by uniting two or more substances or elements by ordinary chemical action in definite proportions.
505
G65. Compressive strength?
The ability of a body to resist crushing expressed usually in terms of tons per square inch.
506
G69. Convection?
The movement of air is called natural convention. A fan or blower moves air by forced convection.
507
G70. Coplanar?
Lying or occurring in the same plane.
508
G71. Copolymer?
The product formed by the simultaneous polymerization of two or more polymerizeable chemicals (monomers).
509
G73. Corrosion?
The chemical or electrical reaction of a substance with other substances in its environment. Usually a destructive reaction.
510
G75. Corrosion rate?
The speed (usually an average) with which corrosion progresses (it may be linear for a while); often expressed as though it were linear, in units of mms (milligrams per square decimeter per day) for weight change of mot (mild per year) or um/y (microns per year) for thickness changes.
511
G76. Crazing?
Small, fine cracks on or under the surface of a plastic.
512
G77. Creep?
The dimensional change, beyond the initial elastic elongation caused by the application of a load, over a specified period of tome. It is normally expressed in inches per inch per unit of time
513
G78. Crevice corrosion?
Localized corrosion resulting from the formation of a concentration cell in a crevice formed between a metal and a nonmetal, or between two metal surfaces.
514
G79. Cross-link polyethylene?
A chemical process creating three-dimensional molecular chains with polyethylene as the base. This process changes the characteristics of PE to make it stronger at higher temperature.
515
G80. Cure?
To change the properties of a polymer to a stable, usable, and final state by the use of chemical agents, heat, or radiation.
516
G81. Dealloying?
The selective corrosion (removal) of a metallic constituent from an alloy, usually in the form of ions.
517
G82. Deflection temperature (heat distortion)?
The temperature which will cause a plastic specimen to deflect a certain distance when a specified load is applied.
518
G83. Degradation?
A deleterious change in the chemical structure, physical properties, or appearance of a plastic.
519
G84. Delamination?
The separation of the layers of material in a laminate.
520
G86. Depolarization?
The elimination or reduction of polarization by physical or chemical means; depolarization results in increased corrosion.
521
G87. Depolarize?
The tendency of positive or negative poles, as in electricity, to become demagnetized.
522
G88. Deposit?
A foreign substance, which comes from the environment, adhering to a surface of a material.
523
G89. Deposit attack (deposition corrosion)?
Pitting corrosion resulting from deposits on a metal surface which cause concentration cells.
524
G90. Deterioration?
A permanent change in the physical properties of a plastic evidenced by impairment of these properties.
525
G91. Dezincification?
The parting the zinc from the alloy. (In some brasses zinc is lost, leaving a weak, brittle, porous, copper-rich residue behind.).
526
G92. Dielectric strength?
The force required to drive an electric current through a specific thickness of a material.
527
G93. Differential aeration cell?
An oxygen concentration cell (a cell resulting from a potential difference caused by different amounts of oxygen dissolved at two locations.
528
G94. Diffusion?
The movement of gas or liquid particles or molecules in a body of fluid through or into a medium and away from the main body of fluid.
529
G96. Discharge head, dynamic?
Static discharge plus pressure need at the end of the pipe, less the frictional resistance of the discharge pipe.
530
G97. Discharge head, statistic?
The vertical distance from the outlet of a pump to the point at which liquid leaves the pipe.
531
G98. Ductility?
The property of a substance which permit it to be drawn thin or worked or extruded.
532
G99. Dry-blend?
A dry compound prepared without fluxing or the addition of a solvent.
533
G103. Elastomer?
A substance which when stretched to approximately twice its length, at room temperature, will quickly return to its original length when the stretching load is relieved.
534
G105. Electrical current?
A current caused by the flow of electrons. However, the electric current flows in a direction opposite the flow of electrons. (This is the positive current concept.).
535
G107. Electrochemical?
Chemical action produced by an electric current.
536
G108. Electrode?
A metal in contact with an electrolyte which serves as a site where an electrical current enters the metal or leaves the metal to enter the solution.
537
109. Electrolysis?
The decomposition of a chemical compound by an electric current whereby chemical changes can take place in an electrolyte.
538
G110. Electrolyte?
An ionic conductor (usually in aqueous solution). A substance whose solutions are capable of conducting electric current.
539
G111. Electromotive force?
The amount of energy supplied by a source of electricity, such as a dry cell, usually measured in volts.
540
G112. Electromotive force series?
An orderly listing of elements according to their standard electrode potentials. (Hydrogen electrode is a reference point and given the value of zero.).
541
G114. Element?
Any of more than 100 fundamental substances that consist of atoms of only one kind and that singly or in combination constitute all matter and which cannot be reduced by ordinary chemical means.
542
G115. Elongation?
The percentage of the original length which a material will deform, under tension, without failing.
543
G116. Emulsion?
A dispersion of one insoluble liquid into another insoluble liquid.
544
G117. Energy?
The ability to do work
545
G119. Environmental stress cracking?
Cracks which develop when a plastic part is subjected to incompatible chemicals and put under stress.
546
G121. Erosion?
Deterioration of a surface by the abrasive action of moving fluids. This is accelerated by the presence of solid particles or gas bubbles in suspension.
547
G122. Erosion-corrosion?
A corrosion reaction accelerated by velocity and air abrasion.
548
G123. Erosive?
Having the property of eating away, corroding or wearing away.
549
G124. Ester?
The compound formed during the reaction between an alcohol and an acid. Sil'.
550
G127. Evaporator?
That part of a refrigeration system in which the refrigerant absorbs heat and evaporates.
551
G129. Extrusion?
The process used to continuously form a shape by forcing a heated or unheated plastic through a shaping orifice (die).
552
G130. Ferric hydroxide?
A compound formed by the union of an element containing iron to form rust.
553
G131. Ferritic?
Pertaining to the body-centered cubic crystal structure of many ferrous (iron-base) metals.
554
G133. Filler?
A relatively inert material added to a plastic to modify its strength, permanence, working properties, other qualities, or to lower costs.
555
G136. Flexural strength?
The measure of a material's ability to withstand a specified deformation under a beam load (bending) at 73*F. Normally expressed in psi.
556
G137. Flow, streamline (laminar)?
The molecules of water tend to move in straight lines with the layer of molecules in the water in contact with the pipe walls moving the slowest.
557
G138. Flow, turbulent?
Causes a large pressure drop because of the thrashing of the molecules against themselves and against the walls of the pipe.
558
G139. Force?
May be defined as a push or pull.
559
G140. Force, centrifugal?
A weight trying to move away from the center of rotation.
560
G141. Forming?
A process in which the shape of plastic prices such as sheets, rods, or tubes are changed to a desired configuration.
561
G142. Formulation?
The combination of ingredients used to make a finished plastic product. Also see compound.
562
G143. Fretting corrosion?
Metal deterioration caused by repetitive slip at the interface between two surfaces. When metal loss is increased by corrosion, the term fretting corrosion is used.
563
G144. Friction?
The resistance to motion of two bodies in contact.
564
G146. Fulcrum?
The fixed point of a lever.
565
G147. Fuse?
To join plastic parts by softening the material with heat or solvents.
566
G148. Fusion?
Also known as melting, is the process of changing from a solid to a liquid.
567
G149. Gage pressure?
Pressure measured where atmospheric pressure is considered as 0.
568
G150. Galvanic?
Pertaining to an effect caused by a cell; often dissimilar metal contact which results in electrolytic potential.
569
G151. Galvanic cell?
A cell consisting of two dissimilar metals in contact with each other and with a common electrolyte (sometimes refers to two similar metals in contact with each other but with dissimilar electrolytes).
570
G152. Galvanic corrosion?
Corrosion that is increased because of the current caused by a galvanic cell.
571
G153. Gate?
The constriction in the flow channel between the runner and the mold cavity in an injection mold
572
G154. Glass transition?
The reversible change in an amorphous polymer from (or to) a viscous condition to (or from) a hard and relatively brittle one.
573
G155. Glass transition temperature?
The approximate midpoint of the temperature range over which the glass transition takes place.
574
G156. G.R.P.?
Glass reinforced polyester; any of several groups of polymeric resins with ester groups in the main chain. More rigid than most of the other polymer plastics.
575
G157. Grain?
A portion of a solid metal (usually a fraction of an inch in size ) in which the atoms are arranged in an orderly pattern. The irregular junction of two adjacent grains is known as a grain boundary.
576
G159. Gusset?
A piece used to give additional size or strength to a plastic part at a particular location.
577
G160. Hardness?
The measure of a material's ability to resist indentation.
578
G161. Head?
The vertical distance measured from the free surface of a liquid to the point at which the pressure is taken.
579
G162. Heat?
A form of energy created by the molecular motion of a substance. Heat is a measure of the total kinetic energy of all the molecules contained in a substance. The weight and temperature of the substance must be known.
580
G163. Heat of compression?
Is heat which becomes (flashes into) a vapor when it is compressed. The source of this heat is the compressor which converts mechanical energy to heat energy.
581
G165. Holiday?
A hole or gap In a protective coating.
582
G166. Homhgeneity?
The state or quality of having like characteristics or uniformity nature, composition, or structure.
583
G167. Hoop stress?
The circumferential stress imposed on a pipe wall when exposed to an internal pressure load. Usually expressed in psig.
584
G168. Horsepower (mechanical)?
A unit of power in the U.S. customary system equal to 33,000 foot-pounds per minute. A standard unit for measuring power.
585
G170. Hydrometer?
Instrument to measure specific gravity of liquids.
586
G171. Hydrostatics?
The treatment of fluids (liquids) at rest, especially incompressible fluids.
587
G172. Impact strength?
A measure of a plastic part's ability to withstand the effects of dropping and/or striking. There are two commonly used test methods, Notched Izod and Tup. Notched Uses a pendulum type machine to strike a notched specimen. Tup testing uses a falling weight (tup) to strike a pipe or fitting specimen.
588
G173. Impenetrability?
No two objects can occupy the same place at the same time because matter is impenetrable.
589
G174. Impinge?
To strike, as with a sharp collision which can make an impression on a material. To come into a relationship as if impinging, make an impression.
590
G175. Impingement attack?
Localized erosion-corrosion caused by turbulence or impinging flow at certain points.
591
G176. Impress?
To introduce into a current or conductor by means of an outside source of energy?
592
G177. Inertia?
The property of matter by which it remains at rest or in uniform motion unless acted upon by some external force.
593
G178. Inhibitor?
A substance used in corrosion control to slow or completely stop a chemical reaction.
594
G181. Ion?
An atom or group of atoms that carry a positive or negative electrical charge as a result of having lost or gained one or more electrons. A free electron or other charged subatomic particle.
595
G182. Iso equation?
The equation which shows the relationship between stress, pressure, and dimensions in pipe.
596
G184. Joule's law?
Defines the mechanical equivalent of heat, showing that 778 ft.-lb. of work = 1 Btu.
597
G185. Ketones?
A group of compounds having two alkyl groups attached to a carbonyl (CO) group.
598
G186. Kinetic?
A characteristic of a moving body as a result of being in motion. When the temperature of a substance is measured the average kinetic energy of its molecules is actually being measured.
599
G191. Lever?
A rigid pies that transmits or modifies force or motion when forces are applied at two points, and it turns about a fixed point.
600
192. Light stability?
A feature of a plastic which allows it to retain its original color and physical properties when exposed to sun or artificial light.
601
G193. Light transmission?
The amount of light which a plastic will allow to pass through.
602
G194. Local action?
Corrosion due to action of local cells; i.e., galvanic cells caused by non-uniformities between two adjacent areas at a metal surface exposed to an electrolyte.
603
G195. Local cell?
A galvanic cell caused by small differences in composition in the metal or the electrolyte.
604
G196. Longitudinal stress?
A tensile or compressive force placed upon the long axis of a plastic part.
605
G197. Long-line current?
Current flowing through the earth from an anodic to a cathodic area which returns along an underground metallic structure (generally applied only where the areas are separated by considerable distance and where current results from concentration cell action).
606
G199. Lussac's law?
States that the volume of a space occupied by a gas is directly proportional to the absolute temperature when the pressure remains constant.
607
G200. Machine?
A device that transmits force or torque.
608
G201. Magnesium (Mg)?
One of the metal elements. A light, silver-white, malleable, ductile metal used often to alloy with other metals.
609
G202. Malleable (malleability)?
The property of a substance wherein it can be hammered or worked into another shape without breaking.
610
G203. Manometer?
A gage constructed of a U-shaped tube of equal legs containing water or mercury used to measure very low pressure (air or water). Reading are in inches of water column or inches of mercury column.
611
G204. Matter?
Anything that has weight and occupies space or has a measurable volume.
612
G205. Mechanical advantage?
The ratio of force that performs work to the force that is applied to the machine, disregarding friction.
613
G206. Mechanical properties?
A term used to describe the properties of a substance relative to forces being exerted upon it.
614
G206. Mercury (Hg)?
One of the metal elements. A heavy, silvery metal which is a liquid below 675 degrees Fahrenheit and solidifies at 39*F.
615
G207. Metal?
A substance that has all or most of the following characteristics: solid at room temperature, opaque, conductor of heat and electricity, reflective when polished, and expands when heated.
616
G208. Metering device?
Acts as a restriction to regulate the flow of liquid refrigerant. It separates the high pressure part of a refrigeration system from the low pressure area.
617
G209. Micro-cell?
One millionth of a cell.
618
G210. Microstractural?
The detailed and precise formation of a metal as shown by microscopic examination.
619
G211. Mild steel?
An iron alloy composed primarily of iron and carbon. Mild steel is the common form of steel used in the piping industry.
620
G212. Modulus?
A term used to describe the load required to cause a specified percentage of elongation. It is usually expressed in psi or kilos per square centimeter.
621
G214. Monomer?
A low-molecular-weight substance whose molecules can react with other molecules to form a polymer.
622
G216. Nickel (Ni)?
One of the metal elements. A hard, silver-white, malleable metal used extensively in plating and alloying due to its resistance to corrosion.
623
G217. Noble?
Referring to positive direction of electrode potential, thus resembling noble metals such as gold and platinum.
624
G218. Noble metal?
A metal (such as gold, silver, or platinum) or alloy relatively superior in resistance to corrosion or oxidation.
625
G219. Noble potential?
A potential in the general range of the noble metals; I.e., strongly cathodic to the standard hydrogen potential.
626
G220. Monograph?
A graph (any chart representing numerical relationships) consisting of three complainer curves, usually parallel straight lines, each graduated for a different variable so that a straight line cutting all three curves intersects the related values of each variable.
627
G224. Nucleus?
The positively charged central part of an atom.
628
G225. Nylon plastics?
Plastics based on resins composed principally of a long- chain synthetic polymeric amid which has recurring amid groups as an integral part of the main polymer chain.
629
G227. Olefin?
A series of unsaturated open-chain hydrocarbons containing one double bond.
630
G228. Olefin plastics?
A group of plastics based on polymers made by the polymerization or copolymerization of olefins with other monomers, with the olefins being at least 50% of the weight. Polypropylene, polyethylene, and polybutylene are examples.
631
G229. Ore?
A combination of minerals from which metal can be extracted.
632
G230. Organic chemical?
Any chemical which contains carbon.
633
G231. Orifice?
A carefully manufactured hole of a specific diameter used to regulate flow, or a plate with a specific diameter hole incorporating pressure gages on either side used to measure flow.
634
G233. Oxygen concentration cell?
A galvanic cell caused by a difference in oxygen concentration at two points on a metal surface.
635
G234. Parallel circuit?
A circuit with more than one current path.
636
G235. Parting?
The selective corrosion of leaching of a component from an alloy such as the parting of zinc from brass, leaving a copper residue ( sometimes known as fez invigoration, depraseodymization, etc.).
637
G236. Pascal"s law?
A confined liquid transmits pressure equally in all directions and this pressure acts at right angles to all surfaces.
638
G237. Passive?
Ability of being inactive and resistant to chemical activity.
639
G238. Permeable?
Having pores or openings that permit liquids or gases to pass through.
640
G239. pH?
The hydrogen-ion activity in gram equivalents per liter used in expressing both acidity and alkalinity on a scale whose values run from 0 to 14, with the lower the number less than 7 indicating increasing acidity and number greater than 7 increasing alkalinity.
641
G240. Phenolic plastics?
A group of plastics based on resins made by the condensation of phenols with aldehydes.
642
G241. Phenomena?
An observable fact or event. A fact or event of scientific interest susceptible to scientific description and explanation.
643
G242. Physical change?
A change in a substance which does not affect the chemical composition (A change of state as water boils into steam).
644
G243. Physical properties?
The inherent properties of a substance such as magnetism, electrical and heat conductivity, and density.
645
G244. Pig iron?
Crude iron as it is drawn from the blast furnace.
646
G245. Pitot tube?
A bent tube open at both ends which is partially immersed in a moving body of fluid with its mouth directed upstream, used to measure velocity head.
647
G246. Pitting?
Highly localized corrosion resulting in deep penetration at only a few spots.
648
G247. Plastic?
A material that contains as an essential ingredient one or more organic polymeric substances of large molecular weight, is solid in its finished state, and at some stage in its manufacture or in its processing into finished articles, can be shaped by flow.
649
G248. Plasticity?
The property of plastics which allows them to be formed, without rupture, continuously and permanently by the application of a force which exceeds the yield value of the material.
650
G249. Plasticizer?
A substance incorporated in a plastic to increase its workability, flexibility, or distendibility.
651
G250. Plastic pipe?
A hollow cylinder of a plastic material in which the wall thickness are usually small when compared to the diameter and in which the inside and outside walls are essentially concentric.
652
G250. Pneumatics?
The study of gases.
653
G251. Polarization?
The process by which gases produced during electrolysis are deposited on the electrodes of a cell, giving rise to a revers electromotive force caused by the products formed or concentration changes in the electrolyte.
654
G252. Polybutylene?
A thermoplastic polymer used in the manufacture of tubing and pipe.
655
G253. Polybutylene plastics?
Plastics based on polymers made with butene as essentially the sole monomer.
656
G254. Polyethylene?
An olefin polymer thermoplastic resin of ethylene.
657
G256. Polymer?
Any two or more polymeric compounds, especially one with a high molecular weight.
658
G259. Polypropylene?
An olefin polymer thermoplastic resin of propylene.
659
G262. Polyvinyl chloride plastics?
Plastics obtained by the polymerization of vinyl chloride. The addition of various ingredients, such as stabilizers, color ants, lubricants, and fillers enhance the process ability and performance.
660
G265. Porosity?
A term describing a plastic part which has many visible voids.
661
G266. Power?
Power means the rate of doing work. It depends on force, distance and time.
662
G270. Pressure, static?
The pressure which tends to burst the container it is placed in.
663
G272. Pressure drop?
Loss of pressure due to friction as a fluid flows through piping.
664
G273. Pressure rating (plastics)?
The maximum pressure at which a plastic part can safely function without failing.
665
G274. Proton?
The positive charged particles of the nucleus of an atom.
666
G277. Pumps, non-positive displacement?
Liquid enters at the center of rotation of an impeller and is thrown outward into a casing or volute. (Volute and diffuser centrifugal, multistage, propeller, peripheral.).
667
G278. Pumps , positive displacement?
Liquid enters the pump through the suction port and is ejected forcibly out of the discharge port by displacement.
668
G279. Pump, reciprocating?
Pumps that have a backward and forward or an upward and downward motion. (Piston, plunger and diaphragm).
669
G280. Pumps, rotary?
Pumps used to pump oil in hydraulic systems. (Lobe, sliding vane, gear and screw.).
670
G283. Quick burst?
A turn used to describe the amount of internal pressure required to burst a pipe or fitting when the pressure is built up over a 60-70 second interval of time.
671
G284. Radiation?
Heat transfer from a warm body to cooler surroundings.
672
G286. Refrigerant?
A substance which, by undergoing a change in state, releases or absorbs a large amount of latent heat in relation to it's volume.
673
G287. Refrigeration?
The process of removing heat from an area or substance and maintaining that area or substance at a lower temperature.
674
G288. Reinforced plastic?
A plastic with high strength fillers imbedded in the composition, causing some mechanical properties to be superior to those of the base resin.
675
G289. Resin?
A solid or pseudosolid organic material, often having a high molecular weight, which exhibits a tendency to flow when subjected to stress, usually has a softening or melting range, and usually fractures conchoidally.
676
G290. Runner?
The secondary feed channel in an injection mold that runs from the inner end of the sprue to the cavity gate. Also, the solidified piece of plastic which forms in the feed channel when the injection molded part cools.
677
G291. Rust?
An oxidizing process in which oxygen from air combines with iron to form a metallic oxide; water combines with oxide to form rust.
678
G292. Rusting?
Corrosion of iron or an iron-base alloy to form a reddish-brown product which is primarily hydrated ferric oxide.
679
G293. Sacrificial protection?
Reduction or prevention of corrosion of a metal in an electrolyte by galvanically coupling it to a more anodic metal.
680
G296. Selective corrosion?
The selection corrosion of certain alloying constituents from an alloy (as fez invigoration), or in an alloy (as internal oxidation).
681
G297. Self-extinguishing?
A term describing a plastic material which stops burning when the source of the burning is removed.
682
G299. Series circuit?
A circuit with only one current path.
683
G300. Shear strength?
The ability of a material to resist cutting. The shear strength of a material is measured on pounds pressure applied to one square inch of the material and is usually expressed in psi.
684
G301. Shrink mark?
A depression in the surface of a molded plastic part where it has retracted from the mold.
685
302. Silicon iron?
An alloy of silicon and iron used for resistance to acid.
686
G303. Siphon?
A device used to transport a liquid from a higher elevation to a lower elevation utilizing a tube and atmospheric pressure.
687
G305. Softening point?
The temperature at which a plastic changes from rigid to soft.
688
G307. Solution?
That which occurs when one or more substances (usually solids) are dissolved in a liquid.
689
G308. Solvent?
A medium into which a substance is dissolved.
690
G312. Specific heat?
The amount of heat required to produce a specific temperature change in a known substance. The specific heat of a substance is usually compared to water which has a specific heat of one.
691
G314. Sprue?
The primary feed channel that runs from the outer face of an injection mold to the runner or the gate.
692
G315. Stabilizer?
An ingredient added to a plastic compound to inhibit or retard undesirable changes in the material.
693
G316. Stainless steel?
Some of a group of alloys containing steel and other metals which are added to resist corrosion.
694
G317. Standard dimension ratio (SDR) pipe?
A type of pipe in which the dimension ratios are constant for any given class. Unlike schedule for pipe (standards for the wall thickness of pipe),as the diameter increases the pressure rating remains constant for any given class of pipe.
695
G318. Static?
Noting or pertaining to electricity at rest, as that produced by friction as opposed to being produced by an electric current.
696
G319. Static charge?
A charge on a body, either negative or positive.
697
G320. Steam, saturated?
Steam in contact with the water from which it has been generated.
698
G334. Stiffness factor?
A term describing the degree of flexibility in a pies of pipe when subjected to an external load?
699
G335. Stray current corrosion?
Corrosion that is caused by stray currents from some external source.
700
G336. Strength (metal)?
The ability of a material to resist deformation.
701
G337. Stress (metal)?
A force applied to a body which tends to change its shape.
702
G338. Stress (weld)?
Load imposed on an object.
703
G339. Stress corrosion?
Corrosion which is accelerated by tensile stress?
704
G340. Stress-crack?
An external or internal crack in a plastic caused by tensile stresses less than its short-time mechanical strength.
705
G341. Sublimation?
A change of state from a solid to a gas.
706
G343. Suction lift, dynamic?
Static suction lift less the friction resistance of the suction pipe of a pump.
707
G345. Substance?
Matter of a particular composition or makeup.
708
G347. Sustained pressure test?
A test in which a plastic part is subjected to a constant internal pressure load for 1000 hours.
709
G348. Swing joint?
Joints that permit the small amount of movement necessary to allow for pipe expansion which takes place when a pipe is heated.
710
G349. Synthetics?
For purposes of this topic, a group of plastic materials from which pipe and fittings are made.
711
G350. Tear strength?
A measure of a material's ability to resist tearing.
712
G351. Temper?
For purposes of this topic, the hardness of a metal or the act of changing the hardness of a metal.
713
G353. Tensile strength?
The property of a material to resist being pulled apart. Expressed in psi.
714
G357. Thermal expansion (water)?
The increase in volume of water when its temperature is increased or decreased from 39.1*F or 3.8*C. The increase of pressure in a closed system due to the heating and expanding of water.
715
G358. Thermocouple?
A device used to measure toe rapture based upon the principle that an electric current is produced when two dissimilar wires or metals are joined together and the junction is heated.
716
G361. Thermosetting plastics?
A group of plastics which., having been cured by heat, chemicals, or other means, are substantially in fusible and insoluble. They are permanently hardened.
717
G363. Titanium (Ti)?
One of the metal elements. A dark grey, lustrous metal used to clean and deoxidize molten steel.
718
G365. Vacuum?
The absence of all matter from a given space. Negative pressure or pressure below atmospheric.
719
G368. Velocity head?
The height of water column caused by and varying with the velocity of a a liquid; the vertical distance through which a liquid would have to fail to attain a given velocity.
720
G368. Venturi?
A tube with a constricted passage (funnel shaped) to increase the velocity and thus lower the pressure of fluids conveyed through it.
721
G370. Viscosity?
The relative thickness or thinness of a liquid. The property of a liquid which would affect its resistance to flow.
722
G371. Voids?
A term generally used to describe holidays and holes in coatings and metal surfaces.
723
G372. Volatile?
A property of liquids in which they pass away by evaporating.
724
G373. Voltage?
The unit of electromotive force expressed in bolts. One volt when steadily applied to a resistance of one ohm will produce one ampere.
725
G374. Water hammer?
The for e resulting when a liquid traveling at a high velocity is suddenly halted.
726
G375. Weight?
The weight of an object depends on two things the mass (or quantity of matter it contains), and the measure of the earth's attraction for that body.
727
G376. Weir?
A V-shaped notch in a channel used to measure or regulate flow by measuring the depth of the fluid overflowing the notch.
728
G377. Weld line (knit line)?
A term used to describe a mark on a molded plastic part formed by the union of two or more streams of plastic flowing together.
729
G378. Wiping solder?
An alloy of tin and lead used to join brass and lead pipe. The mixture of this alloy is usually about 40% tin and 60% lead by weight.
730
G380. Wrought iron?
An alloy of iron and iron silicate (slag) which is more ductile and corrosion-resistant than iron.
731
G381. Yield point?
The point at which a plastic material will not withstand a stretching force. It will continue to elongate with no increase in load after reaching that point.
732
619. 3 techniques of reducing scale within building potable water systems?
1. Maintaining hot water temperature below a maximum of 140*F. 2. Softening to 80-120 mg/L hardness (as CaCO3). 3. Applying polyphosphate at threshold dosages (generally the least effective method).
733
620. How can tastes and odors that develop within a building can usually be corrected and than prevented?
1. By maintaining a regular cleaning schedule for storage tanks and other locations where organic matter may build up. 2. Disinfect the piping system by circulating a chlorine-containing solution through it.
734
621. How can you solve hydrogen sulfide odors from water distribution line?
Remove magnesium anode rods installed for providing cathodic protection.
735
622. What is successful method of removal tastes and odors of water caused by sources outside a building?
The installation of an activated carbon filter on the incoming water line.
736
623. How can symptoms which develop as a result of corrosion be corrected?
1. Changes to a more corrosion resistant material. 2. Separation of the corroded material from the corrosive water. 3. Changing the water composition to make it less corrosive. 4. Modifying the operating conditions in the system.
737
624. Corrective measures for water with low pH values, high concentration of iron, high temperatures, dissolved minerals, and dissolved oxygen?
1. Acid water may be neutralized with designed filters, or soda ash may be fed with chemical solution feeders. 2. Feed chemicals such as poky phosphates and silicates to form protective films in water systems. 3. WHs should be set only as high as necessary, and temperatures above 140*F avoided. 4. Avoid the use of dissimilar metals where possible.
738
625. Water supply requirements for flush valve type WC and urinal?
1. Flow pressure: WC 10-20psi, U 15psi. 2. Flow in gpm: WC 20-40, U 15. 3. Individual branch size: WC 1", U 3/4".
739
626. What water flow velocities may cause water hammer?
In excess of 15 ft./sec.
740
627. What is the barrel equivalent to US gallons?
1 barrel - 42 US gallons.
741
630. How many grains has pound, ounce, gram?
1 pound - 7000 grains; 1 ounce - 437.5 grains; 1 gram - 15.43 grains.
742
631. How many US tons, pounds has metric ton and how many pounds and kilogram has Us ton?
1metric ton = 2205 lb = 1.1023 US ton; | 1 US ton = 2000 lb = 907.2 kg =0.9072 metric ton.
743
632. How many acre and hectare has sq. mile?
1 sq. mile = 640 acre = 259 hectare.
744
633. How many sq. feet, sq. meter, hectare has acre?
1 acre = 43,560 sq. ft. = 0.0016 sq. mile = 4047 = 0.4047 hectare.
745
634. How many acre and square meter has hectare?
1 hectare = 2.471 acre = 10,000 square meter.
746
635. How many cu. cm. has cu inch?
16.387 cu. cm.
747
636. How many cu. in., cu. yd., cu. meter, US gallon has cu. foot?
1 cu. ft. = 1728 cu. in. = 0.37 cu. yd. = 0.0283 cu. meter = 7.481 US gal.
748
637. How many cu. in., cu. ft., cu. meter, US gal. has cu. yard?
1 cu. yard = 46,656 cu. in. = 27 cu. ft. = 0.7646 cu. meter = 202 US gallon.
749
638. How many cu. ft., cu. yd., US gal. has cu. meter?
1 cu. meter has 35.31 cu. ft., 1.308 cu. yd., 264.2 US gal.
750
639. How many US gal. has liter?
0.2642 US gallon.
751
640. How many cu. in., cu. ft., liter imperial gallon has US gallon?
1 US gallon has 231 cu. in., 0.1337 cu. ft., 3.785 liter, 0.8327 imperial gallon.
752
641. How many lb./sq. ft., in. Hg, ft. water has pound/sq. in.?
144 lb/sq. ft., 2.0359 in. Hg, 2.307 ft. water.
753
642. How many lbs./sq. in., in. Hg, ft. water has 1atmosphere?
1 atmosphere has 14.696 lbs./sq.in., 29.921 in. Hg, 33.9 ft. water.
754
643. How many lbs./sq.in., atmosphere, ft. water has inch mercury?
1 inch mercury = 0.4912 lbs./sq.in. = 0.0334 atmosphere = 1.133 ft. water.
755
644. How many lbs./sq. in., in. Hg has foot water?
1 foot water = 0.4335 lbs./sq.in. = 0.8826 in. Hg.
756
645. How many Btu, joule, kw-hr. has foot-pound?
1 foot-pound = 0.001285 Btu = 1.3556 joule.
757
646. How many ft.-lb., joule has Btu?
1 Btu = 778.2 ft.-lb. = 1054.9 joul.
758
647. How many ft.-lb., Btu, hp-hr has kilowatt-hour?
1 kilowatt-hour = 2,655,656 ft.-lb. = 3,412.8 Btu =1.3412 hp-hr.
759
648. How many ft.-lb., Btu, kkw-hr. has horsepower-hour?
1 horsepower-hour = 1,980,000 ft.-lb. = 2,544,5 Btu = 0.7456 kw-hr.
760
649. How many kilowatt, Btu/min has horsepower?
1 horsepower = 0.7475 kw = 42.41 Btu/min.
761
650. How many horsepower, Btu/min has kilowatt?
1 kilowatt = 1.3410 hp = 56.88 btu/min.
762
3. A difference between the mass of an object and its weight?
The weight of an object depends upon the measure of the earth's attraction for that body.

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