INSTITUTE OF INTEGRATED ELECTRICAL ENGINEERS OF THE PHILIPPINES, INC. (IIEE-ERCSA)
www.iiee-ercsa.org
First IIEE Accredited Foreign Chapter (Charter No. 62)
Most Outstanding Chapter – Overseas for the year
1998, 1999, 2000, 2002, 2003 & 2005
Foreign Chapter Excellence Bronze Awardee 2013
Foreign Chapter Excellence Silver Awardee 2014
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Buried Pipeline
Production Pipeline :
A pipeline transporting oil, gas or water to or from a well.
These include flow lines, test lines, water injection lines
and trunk lines.
Flow lines-a pipeline connected to a well
Test lines-a pipeline that is used for testing an individual well
or group of wells.
Trunk lines-a pipeline designed to distribute or gather product
from two or more wells, typically connecting flow lines
or injection lines to the associated GOSP or WIP.
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Buried Pipeline
Cross Country Pipeline:
A pipeline between; two plants areas, another cross-country
pipeline and a plant area, or between two cross-country
pipeline.
Transmission Pipeline:
A cross country pipeline transporting product between GOSPs,
WIPs or other process facilities
Utility Pipeline:
A pipeline designed to deliver an end use service product
(typically water, gas or air)
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Deep Anode Bed:
Anode or anodes connected to a common CP power supply
Installed in a vertical hole (typically 25 cm diameter) with a depth
Exceeding 15 m (50ft)
Galvanic Anode:
Anode fabricated from materials such as aluminum, magnesium or
Zinc that are connected directly to the buried structure to provide
cathodic protection without the requirement for an external cathodic
protection power supply. Galvanic anodes are also referred to as
sacrificial anodes
Impressed Current Anodes:
Anodes fabricated from materials such as High Silicon Cast
Iron (HSCI) or Mixed Metal Oxide (MMO) that are immersed
or buried and are connected to the positive terminal of a DC
power supply to provide cathodic protection current. 4
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Project : UBTG-1 Pipeline Replacement Project
Length : 67 kilometer
Diameter of pipe : 56 inches
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Contents
Installation, Testing and References
CP Material Requirements
CP Performance Criteria
General Design Requirements
What is Cathodic Protection?
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“Cathodic protection (CP) is a technique
used to control the corrosion of a metal
surface by making it the cathode of an
electrochemical cell”.
What is Cathodic Protection ?
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Diagram of a copper cathode in a galvanic cell (e.g., a battery). A positive current i flows out of the Cathode.
A 'Cathode' is a Negatively charged Electrode (or Element) that attracts the Positive (+) ions (Cations) in a Circuit or Chemical reaction. The 'Anode' is the Positively charged Electrode (or Element) that attracts the Negative (-) ions (Anions) in a Circuit or Chemical reaction.
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The simplest method to apply CP is by connecting the metal to be protected with a piece of another more easily corroded "sacrificial metal" to act as the anode of the electrochemical cell. The sacrificial metal then corrodes instead of the protected metal. For structures where passive galvanic CP is not adequate, for example in long pipelines, an external DC electrical power source is used to provide current.
CP Method
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General Design Requirements
Design Considerations
Soil Resistivity Survey Results
Design Current Density
Protection Criteria
System Design Life
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Corrosivity ratings based on soil resistivity
Soil resistivity is a function of soil moisture and the concentrations
of ionic soluble salts and is considered to be most comprehensive
indicator of a soil’s corrosivity. Typically, the lower the resistivity,
the higher will be the corrosivity as indicated in the following Table
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Design Current
Density = 0.10 mA/m² 16
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Design Current
Density = 0.10 mA/m² 17
IIEE-ERCSA Protection Criteria
Pipelines: The negative pipe-to-soil ON potential shall
be a minimum of 1.2 volts and a maximum of 3.0 volts,
with reference to a copper/copper sulfate electrode
Pipeline Valves and associated buried piping: The negative
pipe-to-soil ON potential shall be a minimum of 1.0 volts
and a maximum of 3.0 volts, with reference to a copper/
copper sulfate electrode
For all pipelines, cathodic protection must be achieved
within 30 days of pipeline burial. If this cannot be met,
provide temporary cathodic protection.
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IIEE-ERCSA System Design Life
The design life of cathodic protection system for pipeline shall be
for ≥ 20 years. The design life of anodes shall be calculated
as per SA-SAES-X-400 paragraph 7.2
Formula: Total Anode Weight(Kgs) ≥ 20
Design Life = Anode Cons. Rate x Rect. Rated Current Cap.
Where:
Total Anode Weight, WA =38.6 Kg x 36 nos.
Anode Consumption Rate = 0.45 Kg/A-Y
Rated Current Capacity = 150 A
Design Life = 20.53 years
Using 36 x TA-4 anodes satisfies the minimum requirement design life of
20 years or more
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CP Performance Criteria
Guidelines & Parameters
Surface area to be protected
Calculation of Deep Anode
Temporary CP System
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IIEE-ERCSA Guidelines & Parameter
Guideline/Parameter Value/ Comment
CP system type Impressed Current
Anode installation Deep Well Anode Bed
Anode type High Silicon Cast Iron (TA-4)
Anode Weight net weight 38.6 Kg (SAES-X-400)
Anode current capacity 4.45 A (SAES-X-400)
Anode-bed Active length 11,000cm
Anode-bed diameter 25cm
Nos. of Anodes 36
Anodes Spacing 100cm
Anode consumption rate 0.45 Kg/A-Y (SAES-X-400)
Anode current density 0.7mA/cm² (SAES-X-400)
Life 20 Years (SAES-X-400)
Soil Resistivity 1,400 ohm-cm
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Surface Area To Be Protected
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IIEE-ERCSA System Design Life
The cathodic protection system for pipeline is designed
For ≥ 20 years. The design life of anodes shall be calculated
As per SA-SAES-X-400 paragraph 7.2
Formula: Total Anode Weight(Kgs) ≥ 20
Design Life = Anode Cons. Rate x Rect. Rated Current Cap.
Where:
Total Anode Weight, WA =38.5 Kg x 36 nos.
Anode Consumption Rate = 0.45 Kg/A-Y
Rated Current Capacity = 150 A
Design Life = 20.53 years
Using 36 x TA-4 anodes satisfies the minimum requirement design life of
20 years or more
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IIEE-ERCSA Temporary Cathodic Protection System
Design Considerations:
Soil Resistivity: Assume a value of 3,000 ohm-cm
Current Density :
As per SA standard SAES-X-400 specifies
a current of 0.005mA/m² (Table 2)
Protection Criteria:
The negative pipe-to-soil ON potential shall be a minimum
of -1.0 volts and a maximum of 3.0 volts.
Design Life:
As per SA standard SAES-X-400 specifies
The minimum design life of temporary CP shall be
2 years
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CP Material Requirements
ICCP/Transformer Rectifier
Anode
Junction Boxes
Bond Boxes
Test Station
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An air cooled
cathodic protection
rectifier connected
to a pipeline
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An air cooled
cathodic protection
rectifier connected
to a pipeline
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Junction Box
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References
NACE – National Association of Corrosion Engineers
SAES-X-400 – Cathodic Protection of Buried Pipeline
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INSTITUTE OF INTEGRATED ELECTRICAL ENGINEERS OF THE PHILIPPINES, INC. (IIEE-ERCSA)
www.iiee-ercsa.org
First IIEE Accredited Foreign Chapter (Charter No. 62)
Most Outstanding Chapter – Overseas for the year
1998, 1999, 2000, 2002, 2003 & 2005
Foreign Chapter Excellence Bronze Awardee 2013
Foreign Chapter Excellence Silver Awardee 2014
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