API 651

Question 1

What are the four components of a corrosion cell?

Answer 1

• Cathode
• Anode
• Electrolyte
• Metallic Pathway

API 651 4.1.1

Question 2

What is the most common electrolyte for external surface of the tank bottom?

Answer 2

Moist soil

API 651 4.1.1d

Question 3

Which of the four components of a corrosion cell corrodes?

Answer 3

Anode

API 651 4.1.1a

Question 4

Which of the foud components of a corrosion cell does not corrode?

Answer 4

Cathode

API 651 4.1.1b

Question 5

The rate of soil corrosion increases at what pH level?

Answer 5

< 5.0

API 651 5.3.2.1g

Question 6

The rate of soil corrosion decreases at what pH level?

Answer 6

> 8.0

API 651 5.3.2.1g

Question 7

Pitting type corrosion begins at what chloride level?

Answer 7

10 ppm

API 651 5.3.2.1h

Question 8

The corrosion rate of steel may double with what amount of rise in temperature?

Answer 8

Every 18°F above 77°F

API 651 5.4.1

Question 9

Galvanic type cathodic protection systems are normally insatlled on what tank diameters?

Answer 9

< 20’ diameter

API 651 6.2.1

Question 10

How often should a cathodic protection systems be surveyed?

Answer 10

Annually

API 651 11.3.1.2

Question 11

How often should the source of the impressed current of cathodic protection system be surveyed?

Answer 11

Bi-Monthly

API 651 11.3.2.2

Question 12

How often should an impressed current cathodic protection system be surveyed?

Answer 12

Annually

API 651 11.3.2.3