UFC 3-570-06
JANUARY 31 2003
5-8
Use of Isolation on Foreign Structure to Control Interference.................... 5-18
5-9
Use of a Combination of Mitigation Techniques to Control Interference .... 5-19
7-1
Copper/Copper Sulfate Reference Electrode (Half-Cell) ........................... 7-2
7-2
IR Drop Error ............................................................................................. 7-4
7-3
Anode Gradient Error ................................................................................ 7-5
7-4
Contact Resistance Error .......................................................................... 7-6
7-5
Mixed Potential Error ................................................................................. 7-7
7-6
Single Electrode Potential Survey ............................................................. 7-9
7-7
Typical Displayed Readings Using Digital Voltmeter ................................. 7-14
7-8
Readings Recorded by Digital Voltmeter with
Minimum/Maximum Function..................................................................... 7-15
7-9
Examples of Voltage Spiking on Instant-OFF Readings ........................... 7-16
7-10
Positive Reading for Cell-to-Cell Survey.................................................... 7-20
7-11
Negative Reading for Cell-to-Cell Survey .................................................. 7-21
7-12
Rectifier Efficiency ..................................................................................... 7-22
7-13
Testing for a Shorted Dielectric ................................................................. 7-23
7-14
Testing an Installed Dielectric with the Insulated Flange Tester ................ 7-25
7-15
Testing for a Shorted Dielectric using a Pipe Locator ................................ 7-26
7-16
Testing for Shorted Dielectric with Power Supply ...................................... 7-27
7-17
Typical Casing Installation ......................................................................... 7-28
7-18
Testing for a Shorted Casing ..................................................................... 7-29
7-19
Testing for a Shorted Casing with Power Supply....................................... 7-30
7-20
Testing for a Short Between Two Structures ............................................. 7-32
7-21
Testing for a Short Between Two Structures with Power Supply............... 7-33
7-22
Testing for a Short Between Two Structures with Cathodic
Protection on Both Structures.................................................................... 7-34
7-23
Testing for a Short Between Two Structures without Cathodic
Protection on Either Structure ................................................................... 7-36
7-24
Testing for a Short Between Two Structures with Power Supply............... 7-38
7-25
Removing Temporary Anodes (Ground Rods) .......................................... 7-41
7-26
Soil Resistivity by the Four Pin Method (Wenner) ..................................... 7-42
7-27
Two-Pin Method ("Shepard's Canes") of Soil Resistivity Measurement .... 7-44
7-28
Soil Resistivity Measurement Using a Soil Rod ......................................... 7-44
7-29
Soil Resistivity Measurement Using a Soil Box ......................................... 7-45
7-30
Effect of pH on the Corrosion Rate of Steel............................................... 7-46
7-31
Antimony Electrode ................................................................................... 7-47
7-32
pH Measurement with Electrolyte Current Flow ........................................ 7-48
7-33
Typical IR Drop Test Span Installation ...................................................... 7-49
7-34
Calibration of an IR Drop Test Span .......................................................... 7-50
7-35
IR Drop Test Span, Direction of Current Flow ........................................... 7-52
7-36
Null Ammeter Method, Using the Multi-Combination Meter ....................... 7-54
7-37
Cell-to-Cell Polarity on Foreign Structure .................................................. 7-57
7-38
Normal and Abnormal Potentials of Protected and Foreign Pipelines ....... 7-58
vii
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