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Cathodic Protection > Chapter 3 and 4 > Flashcards

Chapter 3 and 4 Flashcards

0
Q

In a rectifier, the transformer alternating current (AC) to direct current (DC)

A

False

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1
Q

The positive lead of the rectifier is always connected to the structure

A

False

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2
Q

Magnesium, zinc and aluminum are common ICCP anodes

A

False

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3
Q

The Department of Transportation requires use of CP on residential propane tanks

A

False

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4
Q

CP can be used him to come structures, but not submerged structures

A

False

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5
Q

Solar panels rectify AC to DC

A

False

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6
Q

Galvanic and impress current cathodic protection frequently uses the same metals for anodes.

A

False

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7
Q

Per DOT guidelines, water lines must be cathodically protected

A

False

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8
Q

CP cannot be used to protect aboveground storage tanks

A

It depends

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9
Q

Which reference is best suited for soil

A

CSE

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10
Q

Positive lead of the voltmeter should be placed on the structure during the structure to electrolyte reading

A

True

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11
Q

Standard hydrogen electrodes are commonly used in the field

A

False

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12
Q

The three criteria recommended by NACE are

A

850 applied 850 off 100 mV of polarization

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13
Q

The native potential can be calculated by

A

The polarization from the polarized potential

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14
Q

IR drop is calculated by subtracting

A

Polarized potential from the applied potential

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15
Q

IR drop must be considered for the -850 mV polarized criteria

A

False

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16
Q

IR drop must be considered for the -850mV applied criteria

A

True

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17
Q

I R drop must be considered for the 100 mV polarization criteria

A

False

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18
Q

-850mV Applied is the most widely used criteria

A

True

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19
Q

The driving voltage of the cathodic protection system must be greater than what to provide effective cathodic protection

A

Driving voltage of corrosion cell

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20
Q

The sole purpose of the cathodic protection ground bed is too?

A

Discharge current

21
Q

When cathodic protection current is applied to a structure, which direction does the potential of the structure shift

A

Active direction also known as negative direction

22
Q

Two methods utilized to produce the Cathodic protection current

A

Impressed current and galvanic anodes

23
Q

Define CSE

A

Copper – copper sulfate electrode the most common reference electrode used to take pipe just saw potential readings

24
Q

Define pipe-to-soil potential

A

The potential of a pipeline at a given location compared to a reference electrode

25
Q

Define the on potential

A

The potential measurement is taken with the CP system energized

26
Q

Define off or instant-off potential

A

The potential measurement is taken with the CP system not energized also known as polarized potential

27
Q

How does the use of underground pipe line coatings affect the current requirement to achieve cathodic protection

A

Hey well coated pipe will need less current to protect the uncoated parts of the pipe

28
Q

What is a possible to protect more miles of large diameter pipe from a single cathodic protection installment than small diameter pipe lines

A

Per Ohm’s law current flow is inversely proportional to total resistance large diameter pipe has a low resistance than small diameter pipe

29
Q

Cathodic despond meant can be avoided if the off-potentials are Below what level

A

-1.1 V (CSE)

30
Q

Which brownbag construction method will produce a small area for protection provide the least effective on the on the potential compared to remote earth

A

Close ground bed

31
Q

A plastic material loosely wrapped around a pipeline that blocks the effectiveness of the cathodic protection current is an example of which type of shielding

A

Insulating barrier

32
Q

A sort of pipeline casing on the pipeline Road crossing which blocks the effectiveness of the cathodic protection current is an example of which shielding

A

Metallic shielding

33
Q

It is a good idea to ensure that reinforcing wire in concrete be allowed to contact the underlying steel which is under cathodic protection to avoid shielding problems. T or F

A

False

34
Q

What is cathodic corrosion and give an example

A

Too much CP applied the alkalinity of the aluminum pipe may become sufficient to break down passive films

35
Q

Which type of cathodic protection system is most likely to cause stray current damage

A

Impressed

36
Q

Three primary criteria used for cathodic protection of underground or submerged steel piping

A

-850 mV with CP applied, -850 mV polarized, 100 mV polarization

37
Q

Which of the three criteria is the most widely used for steel structures

A

-850 mV CSE applied

38
Q

What is the native potential

A

Potential structure before CP is ever applied

39
Q

How can damage be avoided from hydrogen generated in the cathodic protection process

A

Avoid potential’s more negative the -1.05 to -1.1 mV CSE polarized

40
Q

What is a polarized potential

A

Potential across the structure electrolyte interface that is the sum of the corrosion potential and the cathodic polarization

41
Q

How was polarized potential measured

A

Immediately after all current sources have been interrupted

42
Q

How to measure the formation of cathodic polarization for the 100 mV criteria

A
  1. Measure the native potential, 2. Apply CP and allow structure the polarized. 3. Measure the polarized instant off potential. 4. Find the difference of the native and polarized potentials. 5. If greater than 100 mV, criteria is met
43
Q

Describes how to measure the decay of cathodic polarization for the 100 mV criteria

A

Measure the polarized potential (instant off). De-energize CP system and allow structure to depolarize. Measure the depolarize potential. Find the difference from the polarized and depolarized potentials. If greater than 100 mV, criteria is met

44
Q

Which of the following criteria can also be used on metal other than steel

A

The 100 mV polarization

45
Q

Why should the 100 mV polarization criteria not be used in areas where intergranular external SCC is suspected

A

Criteria my place the structure in the range for cracking which is between the native and the -850 mV CSE

46
Q

Which cathodic protection criteria requires the side drain procedure

A

Net protective current

47
Q

Which cathodic protection criteria are used for copper

A

The 100 mV polarization

48
Q

Which cathodic protection criteria are used for copper if it is electrically connected to steal

A

-850 mV CSE with CP applied and -850 mV CSE polarized potential

49
Q

Which cathodic protection criteria is most commonly used for well coated structures that can be cost prohibitive for poorly coated or bear structures

A

-850 mV CSC with CP applied

50
Q

Which cathodic protection criteria is measured directly after the interruption of all current sources

A

-850 mV CSE polarized potential

51
Q

According to the text which four criteria should not be utilized in areas of stray current activity

A

300 mV shift, E log I, 100 mV polarization, Net protective current

Cathodic Protection (6 decks)

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