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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