Chapter 2 - Planning Plumbing Projects Flashcards
1
Q
How early in advance should you choose your material, equipment, and personal requirements at the company level?
A
30 days in advance.
2
Q
How early in advance should you choose material, equipment, and personal requirements at the job supervisor level?
A
Two weeks in advance.
3
Q
How early in advance should you choose material, equipment, and personal requirements at the crew leader level?
A
No less than one week in advance.
4
Q
What is a key aspect to lead times and material availability?
A
Location of the project.
5
Q
How many days do you have to make a change to the schedule when the crew has arrived on the job?
A
You generally have 45 days.
6
Q
What are good supervisors responsible for?
A
Ensuring equipment, material, tools, and other facilities are on the job needed.
7
Q
What books she is you use for planning, estimating, and sizing plumbing systems?
A
The national standard plumbing code, military specifications, job specifications.
8
Q
What type of protection does threaded pipe that is underground require?
A
Coal tar protection.
9
Q
How far apart should water service lines and waste lines be from each other?
A
Not less than 6 feet apart horizontally.
10
Q
What should water service lines and waste lines be placed on inside of the trench?
A
Either undisturbed or compacted earth.
11
Q
How should sanitary drainage and storm building drains be placed inside of the ground?
A
They should be placed in one trench side-by-side.
12
Q
What type of piping material should you use when a building sewer or building drain is installed and filter or unstable ground?
A
Cast iron soil piping.
13
Q
When may you use nonmetallic drains?
A
When laid on an approved continuous supporting system.
14
Q
Why should you pay special attention to joints in the piping system?
A
So that routes do not grow into the piping.
15
Q
What depth should you bury the piping?
A
Below the frost line.
16
Q
What should you in case the piping in when laying under roadways?
A
You should in case the piping with concrete or sleeve it with metallic material.
17
Q
If you have to install the building sewer line in the water service line in the same trench where should you place the water service line inside of that trench?
A
You need to make sure that the bottom of that water pipe is at least 12 inches above the top of the sewer line off to the side laying on a shelf.
18
Q
After meeting the requirements for installing the water service line with the building sewer line what test should you do to test the building sewer line?
A
You should test the building sewer line with a 10 foot out of water or an equivalent test.
19
Q
What decides the flow velocity of the liquid within the pipe?
A
The slope, pitch, grade, or drop per foot.
20
Q
How low should you slope piping 3 inches or less in diameter?
A
No less than a quarter inch per foot.
21
Q
How should you slope piping that is 4 inches or larger?
A
No less than an 8th inch per foot.
22
Q
How does piping benefit from proper sloping?
A
It allows the velocity of not less than 2 ft./s and keeps the pipe free from fouling.
23
Q
What is the minimum slope inch per foot for piping that is 2 1/2” or less?
A
1/4
24
Q
What is the minimum slope inch per foot for piping that is 3 to 6 inches?
A
An 8th inch
25
What is the minimum slope inch per foot for piping that is 8 inches or larger?
1/16th
26
Hey slope drop of more than a quarter inch per foot is bad for piping systems, why?
Slope drops more than a quarter inch per foot make a siphonage of the trap seal.
27
What increases the caring capacity of a drain?
Higher velocity's or greater drop her foot.
28
What makes an effective technical advisor?
Self-study combined with on the job training and field experience.
29
What is the minimum allowable size of typing for building drains?
3 inches but plumbing codes or ordinances require 4 inch pipe as a minimum.
30
Why is going beyond the size of piping that you need for building drains not the best action to take?
The scoring action from liquid and solid waste is lost when the size of the drain is increased above the necessary size.
31
Using too large of a pipe and building drains causes what?
It causes the flow to be shallow and slow and solids settle at the bottom which cost stoppages in line.
32
When using the optimum size piping for building drains how should it flow?
The optimum size piping for building drains should flow half-full under normal use.
33
Why does the optimum piping of building drains flow half-full?
It creates an efficient, natural scouring action and still allows capacity for peak loads.
34
What is the standard method used in determining the size of building drains?
It's the drainage fixture unit system.
35
How do you calculate the total volume of liquid waste?
By multiplying the number and type of fixtures by the unit value.
I.E. 20WC x 6 = 120 total discharge
Minimum pipe size = 4"
Minimum stack size = 4"
36
How would you determine what size piping and slope you would need for draining all of the fixtures in a building?
You take the total drainage fixture unit values and look up the maximum loads for the horizontal drains which will give you the size of the piping that you need. You can find these in table 2-5 of UT advanced.
37
When copper tubing is used for building drain lines what size will it be as opposed to what is shown on the table?
Copper tubing may be one size smaller than what it says on the table.
38
Should the size of building drainage lines ever decrease in the direction of flow?
The sizes should never decrease in the direction of flow.
39
How should you a lemonade any dead ends of the stack?
Dead ends of the stack should have plugged fittings.
40
What is a stack?
It's a vertical line of soil or waste piping.
41
What is the difference between a waste stack and a soil stack?
A waste stack carries liquid waste and a soil stack carries liquid waste and human excrement.
42
Do most buildings have separate soil and we stacks?
No buildings mostly have a single stack known as the soil stack or the soil and waste deck.
43
What are soil stacks usually made of?
Cast-iron piping with caulked joints. They may be made of galvanize steel or copper tubing.
44
How should you size a stack?
In the same way that you size of building sewer. By taking the total drainage fixture unit value and looking at table 2-6 in UT Adavanced
45
When should a soil and we stack be smaller than the largest horizontal branch connected?
Never.
46
Should a 4 x 3 water closet connection be considered as a reduction in pipe size?
No it should not.
47
If there is an offset in the vertical stack when is it okay to size it as a straight vertical stack?
When the offset has a change in direction of 45° or less.
48
When should a relief vent in the drainage piping be installed?
When a horizontal branch connects to the stack within 2 feet above or below the offset.
49
How should a stack with an offset greater than 45° be sized at the top portion that is above the offset?
The stack above the offset should be sized for a regular stack based on the number of drainage fixture units above the offset.
50
How should a stack with an offset greater than 45° be sized at the actual offset portion itself?
the offset should be sized for the building drain.
51
How should a stack with an offset greater than 45° be sized at the portion below the offset?
The stack below the offset should be sized to the offset or the total number of drainage fixtures in the entire stack which ever is larger.
52
If you have an offset in the stack that is greater than 45° what should you install to provide adequate air to an area in the waste piping that might not get much air?
You should install a relief vent for the offset.
53
What is the rule of thumb for connecting a horizontal branch or fixture to the stack that has an offset that is greater than 45°?
You never connect the horizontal branch or fixture to the stack within 2 feet above or below the offset.
54
How big are closet bends in diameter if made of cast iron, steel or PVC?
The closet bend is three or 4 inches in diameter.
55
How big is the closet bend in diameter if it is made of copper?
3 inches.
56
How can you keep lavatory drainage optimal?
You can keep hair from stopping the drain's by using a minimum number of fittings and by eliminating long horizontal runs.
57
What is the minimum pipe size for lavatory wastes?
1 1/4 inches but one and a half inches works better.
58
What size of the waste pipe should be used for wall-mounted urinals?
1 1/2 inches.
59
What size waist pipe should be used for pedestal siphon jet urinals?
3 inches.
60
What material is usually 2 inches in diameter for shower waste piping?
Cast iron or steel.
61
What material is usually one and a half inches in diameter for shower waste piping?
Copper.
62
What size steel or PVC waste piping must be used for domestic kitchen sink that has no garbage disposal?
1 1/2"
63
What size steel or PVC waste piping is used for a domestic kitchen sink that has a garbage disposal?
A minimum of 2 inches.
64
What is another name for service sinks?
Slop sinks.
65
What are the two styles of slop sinks?
Trap to wall
| Trap to floor
66
What is the difference between a trap to wall type slop sink and a trap to floor type slop sink?
A trap to wall type requires 2 inch or 3 inch waste pipes
| A trap to floor requires a 3 inch waste pipe
67
If copper tubing is used for trap to wall type and trap to floor type waste piping for slop sinks what sizing is permitted?
A one size reduction is allowed.
68
What are scullery sinks used for?
Washing large pots and pans and for general scouring purposes.
69
What size waste piping is necessary for scullery sinks?
2" waste pipe because of the grease that passes through them.
70
What size waste piping should you use for drinking fountains?
1 1/4 inch waste piping. And indirect drain should be used.
71
How many gallons per day can a permanent residents person contribute to the sewer?
100 gallons per day.
72
How many gallons can a person in the industrial area per eight hour period contribute?
30 gallons per person.
73
When determining the size of a sewer what factors are considered?
The average rate and the extreme peak rate of flow.
74
What is the typical sewer peak flow for small areas?
Six
75
What is the typical sewer peak flow for large areas?
1.5
76
How would you go about getting the design flow for a sewer system?
By adding peak flow to the allowance for infiltration of subsurface water.
77
What is a typical infiltration allowance for a sewer system?
500 gallons per inch of pipe diameter, per mile of sewer per day.
78
When would additional capacity to provide for population increase being clued into areas?
It would be included for areas that are likely to continue to develop.
79
What percentage would you go over the initial sewer requirements if an area is projected to develop?
25% additional capacity over the initial requirements is advisable.
80
What is each length of pipe from one manhole to the next sized to carry?
It is size to carry design flow at the upper demands of the system.
81
What are the typical minimum sizes for houses, and industrial waste sewers?
6 inch pipes.
82
What are the typical minimum sizes for all other sewers that do not serve houses or industrial waste?
8 inch pipes.
83
How would you allow for expansion and sewer lines?
By selecting a pipe size that will carry the design flow when the pipe is half-full.
84
Which pipe is smoother asbestos cement pipe or concrete pipe?
Asbestos cement pipe.
85
What will carry a greater flow on the inside of the pipe, if the pipe is smooth or if the pipe is rough?
A smoother pipe will carry a greater flow.
86
What does a 1% slope mean?
It means 1 foot of fall in 100 foot length of pipe. About an 8th inch per foot.
87
What does a 0.5% slope mean?
It means 6 inches of fall and 100 feet it's about a 16th inch per foot.
88
Rather than inches what else may slope be expressed in?
Percentage.
89
When a slope in a sewer passes through each manhole how should the slope remain?
Constant.
90
If you put a big pipe and a small pipe next to each other with a drastically decreased depth of flow which pipe will flow faster?
Both pipes might float the same because of the grade, therefore flow velocity is limited by the rate of flow.
91
What are the typical minimum flow velocities for a sewer line?
2 ft./s at the filled design flow and 1.6 ft./s at the average rate of flow.
92
If the velocity is too high inside of a sewer line what will that do to the pipe?
It will erode the pipe.
93
What is the typical maximum velocity for concrete pipe?
15 ft./s.
94
When should the sewer line pipe size be reduced?
Whenever better flow conditions would result.
95
What intervals are manholes placed in sewer lines?
Their place in intervals of 300 or 500 feet.
96
When should preference covers not be used In sewer lines?
They shouldn't be used in sanitary sewer manholes because the openings would let sand grit and surface water in.
97
How are sewers ventilated?
Sewers are ventilated by the stacks of the building plumbing systems.
98
Should storm drainage systems be separate from sanitary sewer systems?
Yes whenever possible.
99
What type of pipe material may you use for storm drains?
The part material may be the same as the ones used for the sanitary system.
100
What type of piping material is used for larger storm drain systems?
Reinforced concrete pipe.
101
Do the joints of the storm drain sewer system need to be watertight?
No it's not required.
102
If you don't put mortar around the joints of the storm drain sewer system then what would you place next to the openings?
Washed gravel.
103
How much should building storm drains be graded?
A quarter inch per foot whenever possible.
104
What type of fittings are used when a change of direction is necessary within storm and sanitary system?
Long radius fittings.
105
Do cleanouts need to be installed one long radius fittings are used in storm and sanitary systems?
No.
106
When are manholes used in the storm and sanitary system?
Outside of buildings want to change in direction is necessary or when two or more lines are connected together.
107
What factors must be considered when sizing building storm drains?
Rainfall intensity, roof size, and the pitch of the roof.
108
Besides using a table what is another method for sizing building storm drains?
One square inch of pipe cross-sectional area for every 100 ft.² of roof area.
109
What is a stream of water in the pipe made of?
It's made up of a series of layers moving at different speeds.
110
When water is moving at different layers inside of a pipe which layer is moving the fastest?
The center layer is moving the fastest.
111
What can slow down flow inside of a supply system?
But friction also known as friction loss can cause drop in pressure of the water.
112
How would you overcome friction loss and a supply line?
By providing more pressure in the pipes were increasing the size of the pipe.
113
What is maximum fixture demand?
It's the total amount of water that would be needed to supply all fixtures if they're being used at the same time for one minute.
114
What is simultaneous fixture use?
It's a probable percentage of the fixtures and use at any given time.
115
When do simultaneous fixture use factors decrease?
It decreases as the number of fixtures increase.
116
What information must you know to estimate the maximum fixed your demand in gallons?
The number and type of fixtures in a completed plumbing system.
117
How would you reduce the maximum fixture demand in a supply system?
By applying the factor of simultaneous use.
118
The factor of simultaneous use is also called?
Probable demand.
119
If a simultaneous use table is not available what is a practical way of figuring out the probable demand for fixtures?
30% of the maximum fixture demand in gallons.
120
What is the minimum practical size for water service line?
The minimal practical size for water service line is three-quarter inch piping.
121
How is the electro chemical theory of corrosion best explained?
By the action that takes place in a galvanic cell.
122
How would you be able to produce a galvanic cell?
By placing two dissimilar metals in a suitable electrolyte.
123
What is an anodic metal?
It is a metal with a negative charge.
124
What is a cathodic metal?
It is a metal that holds a positive charge.
125
In a dry cell battery what is an anode and a cathode made of?
The anode is a zinc case and the cathode is a carbon rod.
126
What are the several types of corrosion?
Uniform
Localized
Compositional
127
What is uniform corrosion?
Direct chemical attack.
128
What is localized corrosion?
Corrosion caused by the electrolytic action of a galvanic cell. In the form of pits, pockets, or cavities.
129
What is corrosion due to mill scale?
Mill scale is embedded into the walls of iron piping during its manufacture and it causes corrosion in iron piping.
130
What is corrosion due to cinders?
It's caused by laying iron pipe on top of cinders which make up dissimilar metals.
131
What type of soil serves as an electrolyte?
Highly ionized soil.
132
What is corrosion due to dissimilarity of pipe surface?
This type of galvanic corrosion occurs when there are bright or polish services on some areas of the pipe that meet with electrolytic soil.
133
When is corrosion due to different soil conditions prevalent?
It is prevalent in highly alkaline areas.
134
What is corrosion due to stray currents?
It's when direct current circuits pass in and out of an electrolyte.
135
How many pounds of pipewall do stray currents corrode within a year?
20 pounds for every ampere of current.
136
What organisms cause of bacterial corrosion in a pipe?
Bacteria slime and fungi.
137
When does corrosion due to bacteria usually happen?
It usually happens in water or soil environments.
138
What is microbiological corrosive action?
It's corrosion due to physical and chemical changes in the soil.
139
Where can microbiological corrosive action be found?
These bacteria are found and waterlogged, sulfate bearing and blue Clay soils.
140
When does microbiological cross of action vary?
It varies with the different seasons of the year.
141
What type of pipes are corroded by sulfide production?
Cast iron and steel pipes.
142
What are the types of compositional corrosion?
Dezincification
Graphitization
Hydrogen embrittlement
143
What are brasses made of?
Zinc and copper.
144
What type of metal does dezincification corrode?
Copper and Zinc alloy's.
145
What is the process of dezincification?
It's when the zinc out of the alloy leaves only copper.
146
What is compositional corrosion?
It's when the composition of metals are altered.
147
What is another word for graphitization?
Graphitic softening.
148
What type of metal does graphitization corrosion alter?
Grey cast iron.
149
What is cast-iron made of?
It's made of iron and carbon and the carbon is in the form of graphite.
150
What happens during graphitization corrosion?
It's when iron dissolves out of the metal and only leaves graphite.
151
What is hydrogen embrittlement corrosion.
It's when metal becomes brittle and corrodes because of the formation of hydrogen on its surface.
152
What type of metal does hydrogen embrittlement corrode?
Steel.
153
When hydrogen is picked up by the steel what type of state does this cause?
It creates an atomic state.
154
What happens when atomic hydrogen on the surface of steel stops?
The hydrogen leaves the metal in a few days and the metal regains its original ductility.
155
What causes stress on a pipeline or structure?
Shifting of various rocks and soils of the earth.
156
What is corrosion caused by non-electrolytes?
It's corrosion that does not use electricity.
157
What type of materials cause corrosion by non-electrolytes?
Vapors, liquids and bacterial organisms.
158
When do non-electrolytic gases and vapors cause corrosion?
It happens when these gases and vapors are subjected to high temperatures.
159
What temperature does hydrogen sulfide vapor cause scaling in iron?
Temperatures between 1400°F to 2000°F.
160
What type of steel resists nonelectrolyte corrosion best?
Hi chromium alloy.
161
How can you resist corrosion caused by non electrolytes?
By keeping gases and vapors away from metal or by using metal that can resist corrosion.
162
What temperature are high carbon steels attacked by hydrogen?
750°F
163
Where does hydrogen gas attack high carbon steels?
At the grain boundaries between the iron and carbon.
164
What type of gas combines with metals at high temperatures?
Oxygen.
165
What process happens when cutting iron with an Oxyacetylene torch?
The oxygen combines with iron.
166
What are the types of non-electrolytic fluids?
```
Liquids like
pure water,
lubricating oil,
fuel oils,
alcohols.
```
167
Where does the corrosion occur with non-electrolytic fluids?
Storage tanks and pipelines that carry not electrolytic fluids.
168
Is water heavier than oil?
Water is heavier than oil.
169
What are the only ways to prevent corrosion from the inside of pipelines and tanks that carry oil?
By removing the water from them or by coating the inside of the pipeline and tanks with a protective film.
170
What can cause microbiological corrosion?
Bacterial organisms.
171
How do bacterial organisms produce corrosive substances?
They produce them and stationary slimy deposits which make carbon dioxide, hydrogen sulfide, ammonia, organic and in organic acids.
172
If the colony of bacteria does not produce corrosive products what does this do to the metal?
It acts as a protective film.
173
How can you reduce biological corrosion?
By creating a barrier coding between the environment and the metal.
174
What is an electrolyte?
And electrolyte is any substance that conducts electricity.
175
How is corrosion due to atmospheric conditions caused?
It's caused by the water in the atmosphere.
176
Is pure water and electrolyte?
No.
177
Is rainwater pure water?
No because it dissolves gases out of the atmosphere.
178
When does water become an electrolyte?
When gases from the atmosphere dissolve into the water.
179
When metal is exposed to an electrolyte what is produced on the surface of the metal?
Galvanic cells.
180
What causes corrosion and metal by electro chemical action?
Galvanic cells.
181
What do impure water and metal produce to cause corrosion?
Galvanic cells.
182
What type of chemical agents cause corrosion?
Acids and salts.
183
If a piece of zinc is exposed to hydrochloric acid what happens?
A chemical reaction that causes corrosion.
184
What chemical agent can corrode aluminum?
Lye
185
What materials are least likely to be affected by scale and corrosion?
Materials that are affected by electrolysis like plastic materials such as PVC and glass.
186
Why are hot water tanks lined with glass?
Because glass does not corrode.
187
What type of pipes resist corrosion?
PVC, glass, vitrified Clay, cement, fiber, asbestos, rubber.
188
What do glass fibers have to be reinforced with to resist corrosion?
Epoxy or polyester resin.
189
What is used to stop electrolytic action and plumbing systems were dissimilar metals meet?
Dielectric bushings.
190
What are dielectric bushings made of?
They're made of nylon and are usually colored.
191
How much pressure can dielectric bushings withstand?
100 psi.
192
What temperatures can dielectric bushings withstand?
Temperatures up to 300°F.
193
What metals are least likely to be affected by corrosion?
Copper, brass, monel, stainless steel.
194
What are coatings and wrappings commonly used for on exterior piping systems?
Their used to prevent corrosion.
195
What are the types of coatings used to prevent corrosion on exterior piping?
Asphalts, coal tars, plastics, mastics, greases and cement.
196
To prevent corrosion what is the most common type of protective coating?
Asphalt coatings.
197
What are the characteristics of asphalt coating's?
They can take considerable abrasion, impact and temperature changes without losing effectiveness.
198
To prevent corrosion what is the difference between asphalt coatings and coal tar coatings?
Coal tar coatings are less expensive than asphalt but wide temperature changes cause coal tar to crack.
199
To prevent corrosion what are some important paint coatings to remember?
Coal tar, asphalt, rubber, vinyl.
200
To prevent corrosion what are coal tar paints good for?
Since it isn't affected by water it's recommended for peers, Marine installations, flood control structures, sewage disposal points and industrial concrete pipe lines.
201
To prevent corrosion what are asphalt paints good for?
Whether resistance, industrial fumes, condensation and sunlight.
202
What are asphalt paints resistant to?
The resistant against water solvency and are used on steel tanks and concrete reservoirs.
203
To prevent corrosion what a rubber based paints resistant to?
Their resistant to acids, alkalis, salt, alcohol, petroleum products and in organic oils.
204
To prevent corrosion what products are rubber based paints used for?
On the inside of metallic and concrete storage tanks.
205
To prevent corrosion if metallic and concrete tanks are submerged under ground or underwater why would you use a special form of rubber based paints?
Because of condensation.
206
To prevent corrosion what is a synthetic resin based paint?
Vinyl.
207
What is the type of paint that is tough, abrasion proof and highly resistant to electrolysis?
Vinyl paint.
208
To prevent corrosion what is the paint that is odorless, tasteless, non-toxic and nonflammable?
Vinyl paint.
209
What is vinyl paint resistant to?
Electrolysis, oils, fats, waxes, alcohol, petroleums, solvents, formic acid, organic acids, ammonium hydroxide, and phenols.
210
When would you use vinyl paint to prevent corrosion?
You would use them on tanks, pipelines, well heads, offshore drilling rigs, pipe using oil industries, railroad hopper cars, dairy brewery equipment, storage tanks and concrete exposed to corrosive environments.
211
Grease that prevents corrosion is made from what?
It's made from a petroleum base and is like wax.
212
To prevent corrosion what temperature would you apply grease on to metal?
You would apply it either hot or cold.
213
To prevent corrosion when would you use concrete coatings on pipelines?
You would use concrete coatings on pipelines that are laid and highly corrosive soils like areas containing acid mine drainage or in brackish marshes.
214
To prevent corrosion how would you make concrete coatings?
You would mix one part Portland cement to two parts of sent and you would mix it well.
215
How thick can you apply concrete coatings I'll pipelines to prevent corrosion?
You can apply it up to 2 inches.
216
To prevent corrosion if concrete coatings are mixed well and tamped around the pipe how long will it last?
40 years.
217
What would you paint a pipeline with to partially prevent corrosion if concrete coatings crack?
You would use bituminous primer.
218
What is effective and protecting pipes against atmosphere corrosion?
Metallic coatings such as galvanizing zinc coatings.
219
What are metallic coatings ideal for?
They are ideal for cold water lines and metals exposed to normal atmospheric temperatures.
220
What temperature does iron become anodic to zinc?
140°F
221
Why wouldn't you be able to use metallic coatings on iron?
Because at high temperatures iron becomes anodic to zinc.
222
What is galvanic cathodic protection?
Its a method used to protect metal structures from corrosion.
223
What deteriorates metal through electrochemical reaction?
Galvanic cell corrosion.
224
Which side of a cell corrodes?
The positive side of a cell corrodes.
225
What happens when positive electric current leaves metal and enters into an electrolyte?
Corrosion occurs.
226
What is galvanic cathodic protection designed for?
It is designed to stop positive current flow which causes corrosion.
227
In galvanic cathodic protection what happens when you stop current flow?
You stop corrosive action by making the anodes disappear.
228
What type of neutralization does galvanic cathodic protection depend on?
The neutralization of the corroding current.
229
What area needs to be polarized for galvanic cathodic protection to work?
Polarization needs to happen to the cathode metal areas.
230
What methods would you use to initiate galvanic cathodic protection?
Sacrificial anode's or impressed currents.
231
What is used with the galvanic anode method?
Sacrificial anodes.
232
Would you be able to use sacrificial anode's and impressed currents together?
Yes.
233
In the galvanic anode method what is the most common type of sacrificial anode made from?
Magnesium.
234
In the galvanic anode method of corrosion protection what is the anode packaged in to optimize it's contact with the electrolyte (soil)?
Bentonite/sodium sulphate.
235
How is the anode connected to the pipeline that it is protecting against corrosion?
It's an insulated wire that's welded to the pipes surface.
236
How does electrical current flow in galvanic anode protection?
It flows from the anode through the conductor (copper wire) to the pipe.
237
And galvanic and I'll protection once the current flows from the anode through the conductor to the pipe what happens?
The current travels through the pipe and protects the pipe from corrosion.
238
In the galvanic anode method how does the anode corrode?
Hey corrodes by giving off ions that migrate into the soil.
239
In the galvanic anode method when the anode dissipates what do you need to do?
You need to replace the anode completely.
240
What method of corrosion protection relies on naturally occurring voltages between two dissimilar metals?
The galvanic anode method.
241
When you use the galvanic anode method on long pipeline how far should you place the anodes from each other?
Every 40 or 50 feet.
242
What is the impressed current method designed to protect?
Large metallic distribution systems such as water supply lines.
243
What is required to power the imprest current method?
An alternating current power source.
244
In the impressed current method what changes the alternating current power to direct current power?
A rectifier.
245
Where does a rectifier pull current from in the impressed current method of corrosion protection?
It pulls it from the anode which flows the current onto the cathode (structure being protected).
246
How does an anode in the impressed current method corrode?
By giving off ions that migrate into the soil.
247
Which gives a wider range of corrosion protection, the galvanic anode method or the impressed current method?
The impressed current method.
248
Why does the imprest current method of corrosion have such a wide range of protection?
Because it uses and external alternating current power source.
249
What field test equipment would you use to install, operate and maintain cathodic protection systems?
```
Volt millivolt meter
Multi combination meter
Resistivity instrument
Buried pipe locator
Protective coating leak detector.
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250
What would you use to measure the potential of rectifiers, batteries, galvanic anodes and sometimes potentials along the earths surface?
You would use a volt millivolt meter.
251
What would you use to determine the distance is being protected against corrosion?
Volt millivolt meter.
252
What instrument records variations and potential and reveals the electrolytic conditions around the structure?
Volt millivolt meter.
253
What range will potentials vary from?
Millivolts to 20 V or more.
254
What recording instrument is designed with a chart that makes one revolution in 24 hours?
Volt millivolt meters.
255
What can be used as a high resistance volt meter, and ammeter, a millimeter, a low resistance volt meter and millivolt meter and a potentiometer voltmeter?
A multi combination meter.
256
What is used to test the corrosive action of soil?
A resistivity measuring instrument.
257
What consists of a probe with two electrodes, an indicating instrument, switches and the required wiring?
A single probe resistivity meter.
258
How would you use resistivity instrument?
You would insert the probe into the ground and apply current to it.
259
What indicates the corrosiveness in the soil?
A resistivity instrument.
260
What locates interferences in the cathodic protection system?
A buried pipe locator.
261
What are the main components of a buried pipe locator?
The directional transmitter and the directional receiver.
262
How many people are required to operate the buried pipe locator?
Two people.
263
When using a berry pipe locator how many feet should operators stand apart from each other?
30 feet apart.
264
When would you know that you found a pipe with the buried pipe locator?
Winamac some more response shows up on the visual meter the receiver and the headphones.
265
What is a holiday detector?
It's a protective coating leak detector.
266
What is used to detect imperfections in pipe coatings?
A holiday detector a.k.a. a protective coating leak detector.
267
Why is a protective coating leak detector called a holiday detector?
Because holidays are imperfections.
268
How does a protective coating leak detector work?
It makes a completed electrical circuit between the pipe and itself to reveal an imperfection that causes a bell to ring, a bulb to light or a buzzer to sound.
269
What is the minimum and maximum life of an anode?
5 to 30 years
270
How many pounds of magnesium is wasted away by electrolysis from an anode per ampere year?
17 pounds of magnesium.
271
How many pounds of zinc are wasted away by electrolysis from an anode per ampere year?
25 pounds of zinc.
272
How do you detect the effectiveness of cathodic protection in and out systems?
By installing test stations.
273
What value does a transformer step down voltage to in an impressed current system?
It steps it down to a value of 12 to 40 V.
274
What units connections must be especially airtight in an impressed current system?
A rectifier.
275
What materials are often used for anodes in an impressed current system?
Aluminum,
Hi silicon cast-iron,
Graphite.
276
Can you use scrap iron and steel in and impress current system and why?
Yes, because they waste away at a rate of 20 pounds per ampere here.
277
When making connections between the anodes and the structures to be protected what type of connection would you use to resist electrolytic action?
Insulated wire.
