API 1632 Cathodic Protection of Underground Storage Systems

Question 1

What are the four components of an electrochemical corrosion cell? (API 1632, Section 2.1)

Question 2

What happens at the anode of the corrosion cell? (API 1632, Section 2.1)

Question 3

What does not happen at the cathode of a corrosion cell? (API 1632, Section 2.1)

Question 4

What happens along the metallic path connecting the anode and cathode? (API 1632,
Section 2.1

Question 5

What is the electrolyte in the case of buried structures such as underground tanks and
piping? (API 1632, Section 2.1)

Question 6

Which component of a corrosion cell is generally created in an area of relatively low oxygen
concentration? In an area of relatively high oxygen concentration? How does this affect
buried tanks? (API 1632, Section 2.2.1.3)

Question 7

What are four soil characteristics that can influence the rate of corrosion on buried steel
structures? (API 1632, Section 2.2.1.4

Question 8

What are the most damaging stray currents? Where do they typically come from?
(API 1632, Section 2.2.2.2)

Question 9

Under what conditions does bimetallic corrosion occur? (API 1632, Section 2.2.2.3)

Question 10

In a bimetallic corrosion cell, where does the most severe corrosion attack occur?
(API 1632, Section 2.2.2.3)

Question 11

How does cathodic protection work? (API 1632, Section 2.3.1

Question 12

What are two methods of applying cathodic protection to underground metal structures?
(API 1632, Section 2.3.1)

Question 13

In a galvanic cathodic protection system, all the elements of a corrosion cell are
intentionally created. What type of metal is used for the anode (the place where corrosion
occurs)? (API 1632, Section 2.3.2.1)

Question 14

As a corrosion cell develops on an underground storage tank where a galvanic cathodic
protection system has been established, what happens at the anode? What happens at the
cathode? (API 1632, Section 2.3.2.1

Question 15

What are seven advantages of galvanic cathodic protection systems? (API 1632,
Section 2.3.2.2)
a)
b)
c)
d)
e)
f)
g)

Question 16

What metal has the most negative potential (greatest negative voltage) when measured
relative to a copper/copper sulfate reference electrode? (API 1632, Table 1)

Question 17

What are four disadvantages of galvanic cathodic protection systems? (API 1632,
Section 2.3.2.3)
a)
b)
c)
d)

Question 18

What materials are used to manufacture anodes in an impressed current cathodic protection
system? (API 1632, Section 2.3.3.1

Question 19

What are five advantages of impressed current cathodic protection systems? (API 1632,
Section 2.3.3.2)
a)
b)
c)
d)
e)

Question 20

What are five disadvantages of impressed current cathodic protection systems? (API 1632,
Section 2.3.3.3)
a)
b)
c)
d)
e)

Question 21

Which type of cathodic protection system is normally required for existing underground
tank installations? (API 1632, Section 2.3.4.1)

Question 22

A plot plan of a cathodically protected facility should identify which components of the
cathodic protection system? (API 1632, Section 2.3.5

Question 23

What are sacrificial anodes usually made of? (API 1632, Section 3.1.1)

Question 24

In what type of soils are zinc anodes best utilized? (API 1632, Section 3.1.1)

Question 25

In what types of soils are magnesium anodes frequently used? (API 1632, Section 3.1.1

Question 26

Because of low driving voltage and low current output, what type of structure is sacrificial
anode cathodic protection usually limited to? (API 1632, Section 3.1.2)

Question 27

Will a cathodic protection system protect metal piping attached to the tank - but isolated
from the tank by nonconductive bushings - when the tank has factory installed galvanic
anodes? (API 1632, Section 3.2.1)
UX

Question 28

Magnesium and zinc anodes are usually supplied in a prepackaged chemical backfill. What are three functions of this chemical backfill? (API 1632, Section 3.4.2)

Question 29

What are two reasons why galvanic anodes should be installed near the bottom of the
structure they are protecting? (API 1632, Section 3.4.3)
a)
b)

Question 30

Why must a structure that is galvanically cathodically protected be electrically isolated from
other buried metal, including piping and electrical conduit? (API 1632, Section 3.5.2)

Question 31

What measurement is the most common criterion for ensuring adequate sacrificial anode
protection for buried tanks and piping? (API 1632, Section 3.6.1)

Question 32

Where should soil access manholes used for making structure-to-soil potential
measurements be located? (API 1632, Section 3.6.2)

Question 33

Where should long-life reference cells used for cathodic protection monitoring be located?
(API 1632, Section 3.6.3)

Question 34

What type of voltmeter is required for making a structure-to-soil potential measurement?
To what are the two leads from the voltmeter connected? (API 1632, Section 3.6.5)

Question 35

What is usually the most economical means of controlling corrosion on existing
underground bare steel petroleum storage tanks and piping systems? (API 1632,
Section 4.1.1

Question 36

What is the source of the direct current in an impressed current cathodic protection system?
(API 1632, Section 4.1.2)

Question 37

Where should rectifiers for impressed current cathodic protection systems be mounted?
(API 1632, Section 4.2.4)

Question 38

What materials are generally used to make impressed current cathodic protection anodes for
use in soil installations? (API 1632, Section 4.3.1)

Question 39

What type of backfill is generally used with impressed current anodes? (API 1632,
Section 4.3.4

Question 40

Which lead of the rectifier (positive or negative) in an impressed current cathodic
protection system must be attached to the structure(s) to be protected from corrosion?
What will happen if the leads are reversed? (API 1632, Section 4.3.4)

Question 41

Why must special care be taken in insulating all buried wires attached to the positive
terminal of the rectifier in an impressed current cathodic protection system? (API 1632,
Section 4.3.6)