00 FELE SP 0024 Cathodic Protection

7/27/2019 00 FELE SP 0024 Cathodic Protection

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El Palito Refinery Expansion Project

Document Title Cathodic Protection

Document No. 00-FELE-SP-0024 Page 2 of 38

FWI Document No. BD0382A-78A4FWI Revision: F02Date: 15/12/2009

EACH REVISION SUPERSEDES PREVIOUS ISSUE, CHANGES ARE INDICATED IN MARGIN BY THE REVISION NUMBER OR A VERTICAL LINE.This drawing embodies proprietary information of the Consortium. This drawing or the material described thereon may not be copied or disclosed in any form o r medium to third parties, or used for other than

the purpose for which it has been provided, in whole or in part, in any manner except as espressly permitted by Consortium

clientfilename: 00-FELE-SP-0024

REVISION INDEX

PAGE REV DATE PAGE REV DATE1 F02 15/12/2009 21 F02 15/12/20092 F02 15/12/2009 22 F02 15/12/20093 F02 15/12/2009 23 F02 15/12/20094 F02 15/12/2009 24 F02 15/12/20095 F02 15/12/2009 25 F02 15/12/2009

6 F02 15/12/2009 26 F02 15/12/20097 F02 15/12/2009 27 F02 15/12/20098 F02 15/12/2009 28 F02 15/12/20099 F02 15/12/2009 29 F02 15/12/200910 F02 15/12/2009 30 F02 15/12/200911 F02 15/12/2009 31 F02 15/12/200912 F02 15/12/2009 32 F02 15/12/200913 F02 15/12/2009 33 F02 15/12/200914 F02 15/12/2009 34 F02 15/12/200915 F02 15/12/2009 35 F02 15/12/200916 F02 15/12/2009 36 F02 15/12/2009

17 F02 15/12/2009 37 F02 15/12/200918 F02 15/12/2009 38 F02 15/12/200919 F02 15/12/200920 F02 15/12/2009

* Asterisk represents pages revised for this issue.

Initial issueX Entire specification reissued

Revised pages only attached

Please replace revised pages with those now in your possession.


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TABLE OF CONTENTS

1. GENERAL ..................................................................................................................................... 62. CODES, STANDARDS AND REGULATIONS ............................................................................... 73. BASIC ENGINEERING DATA ....................................................................................................... 84. EQUIPMENT AND STRUCTURES PROTECTED USING CATHODIC PROTECTION ................. 95. REQUIREMENTS ........................................................................................................................ 106. DESIGN ....................................................................................................................................... 137. CATHODIC PROTECTION UNITS .............................................................................................. 178. IMPRESSED CURRENT GROUND BEDS .................................................................................. 199. GALVANIC ANODES .................................................................................................................. 2110. TEST POINTS.......................................................................................................................... 2211. INSULATION FITTINGS .......................................................................................................... 2312. PROTECTION FROM STRAY ELECTRIC CURRENTS .......................................................... 2513. INSULATING FITTINGS PROTECTION SYSTEMS ................................................................ 2714. GALVANIC COUPLES ............................................................................................................ 2815. MATERIAL AND EQUIPMENT STANDARDS ......................................................................... 29


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TABLES INDEX

Table A EQUIPMENT AND STRUCTURES PROTECTED USING CATHODIC PROTECTION ........ 9Table B RECOMMENDED POTENTIAL CRITERIA for OFF-SHORE PIPELINES .......................... 11Table C - LOCATION OF ELECTRICAL TEST POINTS FOR POTENTIAL MEASUREMENT ........... 37Table D - LOCATION OF ELECTRICAL TEST POINTS FOR CURRENT MEASUREMENT ............. 38


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1. GENERAL

1.1. Purpose

1.1.1. This specification defines the technical requirements governing design, supplyinstallation and testing of cathodic protection system for buried carbon steelpipelines and other structures as required.

1.1.2. The Material Requisition and Data Sheet shall define the specificrequirements for each application, which take precedence over thisspecification.

1.1.3. Compliance with this specification does not relieve the manufacturer nor thevendor of the responsibility for furnishing equipment of proper design andconstruction and fully suitable for all specified operating conditions.

1.2. Abbreviation and Definitions

Company Petrleos de Venezuela, S.AConsortium PMT Consortium Project Management Team

(Directorate)TEC Toyo Engineering CorporationFWI Foster Wheeler ItalianaY&V Y&V Ingeniera y ConstruccinVendor Supplier of requested Equipment

Project Name and References

Formal name El Palito Refinery Expansion Project.Abbreviated name RELPLocation Refinera El Palito, Carretera Morn

Puerto Cabello Municipio Mora, SectorPunta Chavez, Edo, CaraboboVenezuela


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2. CODES, STANDARDS AND REGULATIONS

Except where indicated otherwise in this specification, the design, equipment,materials, and installation thereof, shall conform to as a minimum, theapplicable requirements of the following standards and codes:

2.1. Local codes and regulations

- FONDONORMA 0200: 2004 - Cdigo Elctrico Nacional

2.2. International Codes and Standards

Engineering design and Manufacturing shall comply with latest edition ofhere below applicable International Codes and Standard valid up untilDecember 2007.

Any deviation or contradiction of such standards to the abovementioned Venezuelan codes shall be highlighted and submitted, inwritten, by involved Manufacturer / Contractor to PDVSA srepresentative for approval.

2.2.1. US Codes and Standards

API RP 1109 Marking Liquid Petroleum Pipeline Facilities,American Petroleum Institute

API RP 651 Cathodic Protection of Aboveground PetroleumStorage Tanks

ASTM A123 Standard Specification for Zinc (Hot-DipGalvanized) Coatings on Iron and Steel Products,American Society for Testing and Materials

ASME B31.3 Process Piping

ASME B31.4 Pipeline Transportation Systems for LiquidHydrocarbons and Other Liquids

AWWA C203 Coal-Tar Protective Coatings and Linings for SteelWater Pipelines - Enamel and Tape - Hot Applied,American Water Works Association.

NACE RP0169 Control of External Corrosion of Underground orSubmerged Metallic Piping Systems, NationalAssociation of Corrosion Engineers


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BS 7361-1 Cathodic protection. Code of practice for land andmarine applications

2.2.2. International Codes

ISO 15589 Petroleum and natural gas industries -- Cathodicprotection of pipeline transportation systems

3. BASIC ENGINEERING DATA

3.1. Project Design Conditions

3.1.1. For equipment design and the Site environmental conditions see thedocuments No. 00-PPRO-BD-0001 Basic Engineering Design Data (BEDD).

3.1.2. For Voltage Levels, See Doc. N00-FELE-SP-0 025, General Notes forElectrical Equipment and Materials.


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5. REQUIREMENTS

5.1.1. A cathodic protection system shall be installed for all the equipments andstructures mentioned in Table A EQUIPMENT AND STRUCTURESPROTECTED USING CATHODIC PROTECTION to mitigate corrosion thatmight result in structural failure. A test procedure shall be developed todetermine whether adequate cathodic protection has been achieved.

5.1.2. Recommended Potential Criteria required for ON-LAND Pipelines (and for theequipment as listed in table Table A) are the following:

The CP system shall be capable of polarizing all parts of the buriedpipeline to potentials more negative than 850mV referred to GSE,and to maintain such potentials throughout the design life of thepipeline (and for the equipment as listed in table Table A). Thesepotentials are those which exist at the metal-to-environment interface,i.e. the polarized potentials.

5.1.3. Recommended Potential Criteria for OFFSHORE Pipelines (and for the

equipment as listed in table Table A) are the ones indicated in the followingTable B RECOMMENDED POTENTIAL CRITERIA :


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Table B RECOMMENDED POTENTIAL CRITERIA for OFF-SHOREPIPELINES

Material Minimum Negative Potential[V]

Maximum Negative Potential[V]

CARBON STEELAerobic EnvironmentAnaerobic Environment

-0.80-0.90

-1.10b)

-1.10b)

AUSTENITIC STAINLESSSTEEL

N PRE 40c)

N PRE < 40c)

DUPLEX STAINLESSSTEEL

MARTENSITIC STAINLESS(13% Cr) STEEL

-0.30d)

-0.50d)

-0.50d)

-0.50d)

-1.10-1.10

e)

e)

The potential given in the table, apply to saline mud and normal seawater compositions (salinity 3.2% to3.8%).The potentials are referenced to an SCE reference electrode, which are equivalent to a silver/ silverchloride reference electrode (Ag/ AgCl/ seawater), in 30 cm seawater.

a) These negative limits also ensure negligible impact of CP on pipeline coatings.b) Where pipelines systems are fabricated from high strength steel (SMY > 550 MPa), the most

negative potential that can be tolerated without causing hydrogen embrittlement shall beascertained.

c) N PRE = % Cr + 3.3 % (Mo+0.5W) + 16 %Nd) For stainless steels, minimum negative potentials apply for aerobic and anaerobic conditions.e) Depending on strength, specific metallurgical condition and stress level encountered, these alloys

can be susceptible to hydrogen embrittlement and cracking. If a risk of hydrogen embrittlementexists, then potentials more negative than 0.8 V should be avoided.

5.1.4. The need of temporary cathodic protection system shall be evaluated andapplied, if, due to the construction schedule, underground pipelines shall notbe operational for more than one year. When cathodic protection alreadyexists, the new CP system for the new structure must be designed with theconsideration on that. Information about the existing CP shall be given toContractor /Vendor by PDVSA representative.


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5.1.5. Design and selection of the cathodic protection system to be utilized shall bebased upon this specification and sound engineering judgment, substantiatedby:

- Adequate corrosion survey data- Review of historical data from similar facilities- Economics- Material, operational and environmental requirements

5.1.6. The resultant cathodic protection system shall be designed to eliminate anyadverse corrosive effect upon nearby structures, equipment, pipe, cables, etc.owned by others or by the government. In addition, design drawings shallclearly define the location of all cathodic equipment incorporated on thepipeline system and all other facilities, whether above or belowground thatcould affect or be affected by the cathodic protection system. The systemdesign life is 20 years.

5.1.7. Cathodic protection system shall be designed with the consideration of pipeexternal coating. The design basis for the pipe external coating shall beapproved by Contractor

5.1.8. Materials and equipment shall conform to the referenced standards or asapproved by Consortium for special requirements. When required,representative sample batch materials suitable for destructive testing shall befurnished to buyer for quality control inspection and approval prior to deliveryof corrosion prevention materials. A copy of the manufacturers analysis ortest results shall be furnished with the representative sample. All otherequipment will be subject to Consortium/ Companys acceptance inspection.

5.1.9. The Vendor shall provide as built drawings of the installation.


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6. DESIGN

6.1. Site Surveys

Field data are required prior, to proceed with design studies followingthe survey requirements.

6.1.1. Surveys

The survey method to be used for this project shall consist in rapid orspot testing of soil resistivity at typical points along the structure. Theenvironmental conditions, size, physical layout, economics and needfor design information will determine which variables require fieldmeasurement.

6.1.2. Data accumulation

Proper data recording in the field is mandatory. In additions toelectrical measurement, recorded data shall include dates, weatherconditions, soil conditions, names of survey personnel, telephone

numbers and addresses of foreign contacts, terrain description, entryroads, potential sources of electric power, locations suitable forsacrificial anodes an other such pertinent information.

Survey data shall also indicate the location of all buried structures onand adjacent to the job site, the condition of exposed metal surfacesand the insulating qualities of any coatings on such structures.

Detailed location measurements, such as for possible cathodicprotection locations, shall be properly references by a triangulationsystem to property lines, kilometres posts, and/or established surveystations.

6.1.3. Testing facilities

Complete cathodic protection design parameters shall be obtained byinstalling a temporary cathodic protection system and measuring thequantity of protective current required to adequately protect a givenburied system. Details of these temporary cathodic protection facilitiesare given below:

6.1.3.1. Location

The temporary ground bed shall be located at the site selected for theproposed permanent facility.


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6.1.3.2. Temporary power sources

Temporary electrical test power may consist of enginedrivengenerators, storage batteries, existing cathodic protection units,portable rectifiers combined with available commercial power, etc. Thisequipment shall be capable of providing wellregulated constant directcurrent voltage and amperages of required magnitudes for theparticular test duration.

6.1.3.3. Temporary ground beds

Temporary ground beds may consist of buried junk pipe, abandonedburied metallic structures, aluminium foil in burrow ditch water, etc.which may be utilized to provide sufficient electrical ground contact toallow stimulation of the proposed ground beds. Temporary wiring usedfor connecting the ground bed shall have sufficient insulation toprevent uncontrolled circuits and to provide personnel safety.

6.1.3.4. Current measurement

After the system has stabilized at the required protective levels,measurements shall be made of current drainage at all current sourceincluding control bonds.

All current measurements shall be obtained across calibrated shuntsor from instruments permanently connected in the circuit wherebyresistance will remain constant during the tests.

6.1.3.5. Soil to pipeline potential measurement

Soil to pipeline potentials shall be obtained at all test leads; both sidesof insulating flanges or unions, foreign pipeline or other buried metallic

structure crossings, or like structure in a close proximity to thestructure being protected (where such readings are practical andobtainable); and elsewhere as deemed necessary to establish theeffectiveness of the proposed cathodic protection system and toassure against induced stray current corrosion on structures not to beincluded into the cathodic protection scheme.

All potential readings shall be recorded to the nearest millivolt usingsuitable precision instruments and standard coppercopper sulphate(Cu/CuO4) half cell reference electrodes, or silversilver clorure(Ag/Ag Cl) half shell reference electrodes.


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Potential readings shall be taken at sufficient intervals to prevent overlooking a nonprotected or corroding portion of the buried structure tobe protected.

Readings shall also be obtained to ascertain that the cathodicprotection system being designed will not create noncontrollableinterference problems upon other buried structures. In locationssubject to volatile explosion, such as station and tank farm

installations, additional potential readings shall be in sufficient numberto detect any hazardous condition, which may result from the cathodicprotection installation.The electrode position with respect to the buried structure shall berecorded for each potential measurement.

6.1.3.6. Measurements conditions

No applied current This is the socalled normal or native electricalcondition of the buried structure. These conditions are to be shiftedby applied cathodic protection to an electrical state meeting one ormore of the applicable protective criteria as described in NACE RP

0169, Section 6, Criteria for Cathodic Protection. Choice of criteriashall be governed by economics, coating condition, environment andtype of buried structure to be protected.

Minimum protective level Using the temporary simulated cathodicprotection system enough protective current shall be drained from thestructure to establish protection over the entire structure meeting theminimum levels acceptable for criteria being applied.

Maximum protective level After the minimum protective currentrequirements have been determined, the current output of thetemporary simulated cathodic protection system shall be increased

until the upper limits of the acceptable protective levels have beenreached. Protective attenuation across the entire structure shall thenbe measured.

6.1.3.7. Soil resistivity survey

Soil resistivity survey measurements shall be obtained using the fourelectrode method.

Pipeline Route Where resistivity measurements are required alongthe pipeline, they shall be made at maximum intervals of 1 km (or lesswhen the soil conditions change) using electrode spacing equivalent topipe depth.


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Ground Bed Sites Resistivity readings at proposed ground bedlocations shall be taken to allow complete resistivity contouring at eachalternate proposed ground bed site.

Anode Sites Resistivity readings at proposed galvanic anode sitesshall be taken along the pipe at suitable intervals using potentialelectrode spacing as required.Resistivity readings shall be corrected to consider the worst resistivityconditions, that is, summer conditions.

Soil Samples Suitable soil sample shall be obtained when necessaryto determine additional soil characteristics such as soluble salts,moisture content, ph, etc. The content of sulphate shall be determinedto detect the presence of sulphatereductor bacterias.

The single pin method will be acceptable only when the four-pinmethod cannot be used because of space or other limitations.

6.1.3.8. Locating buried pipelines

Electronic pipe locators may be used to locate underground pipelines

or other metallic buried facilities. Spotting bars shall be used only toverify underground location. Coating on the buried structure shall notbe damaged by use of the bars.

6.2. Design Studies and Documentation

The Vendor shall prepare detailed designs of proposed protectionsystem.

Proposals shall:

- Be based on a continuous operation of the system for the specifieddesign life of the structure or equipment to be protected.

- Include installation requirements of any bonds necessary betweenstructures, which may be subject to cathodic interference.

- Include details for system commissioning, the design and location ofinsulating flanges, and monitoring points.

- Proposal information above mentioned must be approved by theConsortium/ Companys engineer


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7. CATHODIC PROTECTION UNITS

7.1. General

7.1.1. These facilities include such devices as engine driven generator, alternators,rectifiers, ground beds and galvanic anodes that supply protective currentthrough a cable connection to the buried metallic structure. Anticipatedchanges in soil characteristics and in coating efficiency shall be considered

when choosing and sizing cathodic protection equipment.

7.1.2. Rectifiers will usually provide the lowest cost protection current where ACpower is available and where the current demand will exceed thateconomically obtained from galvanic anodes.

7.1.3. Surface ground beds will normally provide maximum longterm economies.

7.1.4. Deep well ground beds are generally higher in first cost than surface beds;however, they may be the longterm economic choice in arid areas orlocations where rightofway acquisition is difficult.

7.1.5. Galvanic anodes provide specific economic and operational advantage in highinterference areas such as offshore environments and when used with hotspot highdielectric coatings such as Xthrucoat and thin film Epoxy.Galvanic anodes are the economic cathodic protection choice for shortpipeline systems.

7.2. Location of Units

7.2.1. Location shall be governed by the following factors:

- Near an existing economic power source such as a government station- DC power source adjacent to the ground bed

- Nonexplosive area- Sheltered and adequately ventilated- Access roads nearby- Low resistance well watered soil


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7.3. Spacing of Units

7.3.1. Spacing shall be governed by the following factors:

- Rectifier and ground bed capacity- Stray current effect- Allowable potentials on coating- Protective coatings insulating and dielectric qualities

- Economics- Soil conditions

7.4. Type of Units

7.4.1. Offtheshelf or catalogue units manufactured in accordance with appropriatestandards are preferred. Type selection is determined by the following:

- Air-cooled single-phase units shall be used for normal requirements.- Oilimmersed units shall be used in locations where high humidity

conditions, high ambient temperatures, harmful corrosive vapors,excessive dust conditions, hazardous explosive vapors, or similar

conditions may be encountered.- Threephase units may be used when such electrical power is available.- Base mounted units shall be used in instances where appearance and/or

weight are controlling factors. Foundations for such units shall be made inaccordance with Project Civil Design Specifications.

- Rectification Element. Generally, Selenium full wave stacks shall be used.Where high current requirements or system economics demand the useof Silicon elements, the elements shall be fully protected with adequate,specially designed surge protectors and lightning arresting device.

7.5. Specialized Units

7.5.1. Rare design problems will require the use of special cathodic protectiondevices such as the constant potential or constant current unit. Problems likevariable ground bed resistance, high voltage direct current interference, andexposure to other severe direct current interference problems, will generallyrequire automatic regulation of cathodic protection current output for completeand economic protection. Special cathodic protection units such as enginedriven generators or alternators shall be selected from manufacturersstandard equipment.


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8. IMPRESSED CURRENT GROUND BEDS

8.1. Location

8.1.1. Selection of ground bed sites shall be based on:

Current Utilization Ground beds shall be located for the maximum utilization ofprotective currents with a minimum flow of interfering currents in the soil circuits.

Accessibility The design should strive minimize rightofway procurement problemswhile providing maximum, accessibility for installation, inspection and maintenance.

Soil Soils having the best combination of low electrical resistivity, high chemicalconcentration and maximum moisture content are preferred for the ground bed site.

Soil to Structure Potential The ground shall be located so that the potential betweenthe coated structure and the soil contacting it shall not exceed the following levels asmeasured to a coppercopper sulphate electrode located directly over the pipe:

CONDITION MAXIMUM POTENTIALHigh resistance Soil, high bond strength coatingHigh resistance Soil, low bond strength coatingLow resistance SoilSea waterBare Pipe Lines

3.0 volts2.5 volts2.0 volts1.3 volts

As limited by interferenceconditions

8.2. Type

8.2.1. The choice of surface versus deep well ground beds shall be governed bysuch variables as annual rainfall, soil conditions, interference problems, andrightofway acquisition costs.

8.3. Anode Selection

8.3.1. Generally, passive type (graphite, cast iron, lead silver) rather than sacrificialtype anodes shall be used. Such anodes shall be surrounded with tampedsoft coal or calcinated petroleum coke breeze when practical in order toincrease effective anode size.

8.3.2. FerroSilicon anodes shall be used for deep well beds and are preferred forsurface beds.


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8.4. Anode Placement

8.4.1. Where feasible, anode placement shall be designed to allow discharge ofnearly equal currents from all anodes in the ground bed.

8.4.2. Surface ground bed anodes shall normally be installed in the preferredvertical position, but where rock or other obstructions are encountered theanodes may be installed horizontally to take advantage of soil conditions at

the particular installation.

8.5. Deep Well Ground Beds

8.5.1. Depth of deep well beds shall be such that the anodes are located in lowresistant strata such as red beds or similar clays. A resistivity log of the holeshall be taken and used to position anodes in the lowest resistant soil strata.

8.5.2. Other design criteria include:

- Low current drain (34 amps per anode) to minimize gassing andpromote longevity

- Anode spacing to take advantage of favorable strata, 1524 mm (60 in.)minimum

- Adequate means for gas venting- Anode centralizers- Coke slurry injection from bottom- Inert or noncorrosive structural materials so that anodes alone

determine effective life, including plastic vent pipe, nylon support rope,stainless steel clamps and centralizers, plastic casing to top of coke fill,etc.

8.6. Current Density

8.6.1. Maximum design current for graphite anodes shall be 3 amperes for 76 mm x1524 mm (3 in. x 60 in.) anodes and 4 amperes for 102 mm x 2032 mm (4 in.x 80 in.) anodes.

8.7. Ground Bed Design Aids

8.7.1. Ground bed resistance may be lowered by increasing number of anodes,anode length, diameter, burial depth or spacing, and by decreasing soilresistivity adjacent to the anodes.


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8.7.2. Spread or throwing power may be increased by increasing the distancebetween the ground bed and the protected structure, by improving the coatingon the buried structure adjacent to the ground bed, or by utilizing mutualinterference between anodes to focus the bed output away from the structure.Continuous ground bed output may be assured by providing for future waterreplenishment.

8.7.3. Gas elimination devices such as vent pipes and drain tiles must be used to

assure continuous full current output. Vent pipes installed in deep well groundbeds shall be drilled with adequately spaced and properly sized holes toinsure against plugging and to provide adequate gas venting.

9. GALVANIC ANODES

9.1. Application

9.1.1. In general, galvanic anodes may be advantageously installed on sections ofburied structure where control of interfering currents is difficult, particularly incongested and urban areas.

9.1.2. They may serve for installations remote from electric power or for protectionof small-insulated sections in a large unprotected system.

9.1.3. Magnesium anodes are frequently the economic cathodic protection choicefor long or complex piping systems coated with longlife, high dielectriccoatings such as extruded plastic and the fusion bonded thin film epoxies.

9.2. Location

9.2.1. Galvanic anodes shall be installed in battery groups at distributed locationsalong the system to provide complete protection and to allow for futureinspection and maintenance.

9.2.2. Soils having the best combination of low electrical resistivity, high chemicalconcentration, and maximum moisture content shall be selected for thegalvanic anode site. Distance for buried structure should not exceed 3048 mm(120 in.).

9.3. Type

9.3.1. Galvanic anode selection shall be restricted to commercially availablemagnesium or high purity zinc anodes.

9.3.2. Zinc anodes shall be used only in low resistance soils and where low currentoutputs and resultant low solution potentials are tolerable.


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9.3.3. Anode size, shape, weight, purity and backfill shall be governed by therequirements of the particular installation in accordance with materialsspecified herein.

10. TEST POINTS

Test points are defined as those points or locations along the protectedburied metallic system at which electrical current or potential

measurements are made to evaluate the level or status of cathodicprotection.

These points shall be provided, within the limits of economical andlogical feasibility, in sufficient quantities and at appropriate intervals tominimize the possibility of overlooking a nonprotected, corrodingportion of the buried metallic structure.

10.1. Potential Measurement

10.1.1. Location

At readily accessible locations convenient to public roads and/orwaterways (See Table C - LOCATION OF ELECTRICAL TESTPOINTS FOR POTENTIAL MEASUREMENT)

10.1.2. Typical test point design

Test points for potential measurement shall consist of welded, metalliccontacts to the buried structure, which provide for efficient cliponmeasurements and reliable repetitive readings. Use of such pointsshall provide for minimum damage to buried structure insulation,prevent contact damage to decorative coatings, and eliminate notchpenetrations into the metallic structure by repeated base metal

contacts.

10.1.3. Other data

In most instances, properly sized and insulated stranded copper wireshall be used to transfer metallic contact from buried structures toconveniently located above ground test terminals. Protruding boltthreads (softer than steel test clips) shall provide the testingconnections at the wire terminal. Suitable rigid conduit connections,risers and boxes are used to protect the test points.Casing vent pipes,pipeline risers, valves, etc. may provide the metallic transfer path fromburied structure to above ground. In such instances short lengths ofsolid or tubular copper shall be welded or soldered to the structure toprovide a test point.


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10.2. Current Measurement

10.2.1. Location

Refer to Table D - LOCATION OF ELECTRICAL TEST POINTS FOR CURRENTMEASUREMENT for location of electrical test points for current measurement

10.2.2. Typical test point design

Test points for measurement of electrical current shall generally consist of calibratedshunt type measuring facilities, which allow measurement of current without breakingthe cathodic protection circuit.

10.2.3. Other data

Standard one millivolt per one ampere (0.001 ohm) suitable capacity shunts shall beused when possible. For galvanic anode installations and low current rectifiers the tenmillivolt one ampere (0.01 ohm) shunt may be used. The shunts shall be contained inproper housings.

Where sacrifice anode systems are used, potential measurements shall be maderemote from the anodes and the number of potential measurements to be made shallbe reviewed with the owners engineer.

11. INSULATION FITTINGS

Insulating fittings shall be designed for above ground installations to control the flowof electrical currents. Where fittings are buried, properly sized leads on either side ofthe insulation shall be brought above ground for current measurement and control. Ooffshore insulated unions or other hardtoreach insulators, spare leads shall beinstalled during construction.

Insulating fittings shall be provided at sufficient intervals along the metallic cathodicprotection circuit to result in adequate circuit control. These insulations shall generallybe installed in already proposed flanges, such as at line block valves, to minimizecost of line electrical insulation.

Selection and design of the insulation fitting (flange or union) to be used shall begoverned by the requirements of the particular application. Material shall be selectedfrom standard manufacture items.


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11.1. Pipeline Insulating Locations

11.1.1. Main lines

Shall be insulated from station and terminal structure, river crossings,and injection connections.

11.1.2. Storage tanks

Shall be insulated from connected buried metallic structure, andproduction tankage shall be insulated from governments system.

11.1.3. Foreign line connections

Shall be insulated from governments line.

11.1.4. Flow lines

Shall be insulated from wells.

11.1.5. Coated selection

Coated pipelines shall be insulated from adjacent uncoated pipelinesections.

11.1.6. Buried flanges and above ground flanges

These shall be provided with sufficient insulation to insulate fully eachbolt from both flanges.

11.2. Special Insulating Points

Typical locations that require special insulating provisions are asfollows:

11.2.1. Valves in valve pits

Shall be insulated at the support point by two sheets of metalseparated by a sheet of insulating material. This insulator combinationshall be completely coated.

11.2.2. Pier supports

Shall be isolated from pipelines by multiple layers of glass wrappersaturated with coating material, or sheet insulating material.


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11.2.3. Cross lines and parallel lines

A minimum space of 305 mm (12 in.) shall be provided between crosslines for insulating purposes. When this spacing cannot be obtained,insulation assurance can be obtained by using sheer insulatingmaterial such as miscast. Thickness of insulating sheet will begoverned by distance between lines, but should not be less than 6.35mm (1/4 in.). When practical the space between parallel lines 6 and

larger should be a minimum of 21/2 times the diameter of the largestline.

11.2.4. Electrical ground connections and conduit

Shall be isolated from coated pipeline sections. Bare copper groundcables shall be spaced at least 305 mm (12 in.) from other burieddissimilar metallic structures.

11.2.5. Public utility lines

Sewer, gas and electricity lines shall be insulated from governments

buried metallic structures.

11.2.6. Buried dissimilar metallic structures

Shall be insulated from each other.

12. PROTECTION FROM STRAY ELECTRIC CURRENTS

Corrosion prevention design of all buried metallic structures shallminimize the probability of stray electric currents flowing betweenexisting and/or proposed facilities. Adequate coatings and/or insulation

shall be provided at anticipated trouble points to minimize the flow ofstray currents. Design shall normally incorporate appropriate bondcircuits between buried metallic structures to prevent the corrosiveeffect of stray electric currents.

12.1. Typical Bond Application

12.1.1. Cathodic protection currents

Shall be controlled to prevent stray current damage by provisions forsolid, resistance, unidirectional, electrolytic or rectifier bonding asrequired by the particular application. Where foreign pipelines areinvolved, a joint interference-testing program is generally required.


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12.1.2. Alternating currents

Where stray or induced alternating currents will be encountered on apipeline (generally, where a well coated line is parallel to a highvoltage transmission line), electrolytic drains such as zinc ormagnesium rods shall be installed to ground the alternating current.This induced alternating current, especially with yard-coated lines, canbe extremely hazardous during construction. Temporary grounding

facilities shall be provided to protect the pipe as it is being installed.

12.1.3. Lead sheath cable currents

Bonds shall be provided at each end of conduit runs to insure nondemanding flow of cathodic protection currents. Lead, aluminum andzinc, if exposed to a severe alkaline environment, will corrode rapidly,even if cathodically protected. Thus, these metals must be maintainedat a potential below 1.2 volts to copper sulphate to prevent buildup ofcathodic protection caused by alkaline products. In cases where higherpotentials, occur, specially designed resistance bonds are required.

12.2. Typical Bond Circuits

12.2.1. Soil bond

A solid low resistance metallic circuit that electrically connects theoffending and offended structures

12.2.2. Resistance bond

Similar to solid bond except that a resistor is placed in the circuit torestrict the operating bonds current.

12.2.3. Electrolytic bond

Similar to resistance bond except that an electrolyte is used in place ofthe resistor.Galvanic anodes may be buried close together or near a buriedmetallic structure to utilize the soil as the electrolytic resistance.

12.2.4. Surge gap bond

Similar to resistance bond except that an air gap resistance is used inplace of the resistor.


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15. MATERIAL AND EQUIPMENT STANDARDS

15.1. General

This section will provide the basic criteria, including quality control andacceptance testing, for material and equipment required for cathodicprotection facilities associated with the handling of crude oil, crude oilproducts, water and other materials transported by pipeline or

associated facility. Unless otherwise specified, only the latest editionsof referenced standards shall be used. Materials used shall complywith all applicable local regulatory requirements.

15.2. Rectifiers

Shall conform to NEMA Standard MR 20 for semiconductor rectifiers cathodic protection units.

15.2.1. Case (or Housing)

Adequately sized cases shall be small arms proof and tamper

resistant. They will be properly galvanized or coated to resistatmospheric corrosion. Oil immersed cases shall be pressure testedfor leaks, and air cooled units shall be screened to prevent insectentry. If located outdoor, the enclosure housing shall be NEMA 4X.

15.2.2. Interior frame

Component parts shall be mounted so that all connections areaccessible. Oil immersed rectifiers shall contain a removable frameupon which immersed parts are mounted. In general, galvanized steelor other atmospheric corrosion prevention coatings shall be used forthe interior frame and bolts in aircooled rectifiers.

15.2.3. Transformers

There shall be a separate transformer for each electrical phase used inthe rectifier.

15.2.4. Rectifying assemblies

All rectifiers shall contain fullWave Bridge connected rectifyingassemblies mounted to minimize heat transfer to the rectifyingelements.


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15.2.5. Terminals and connections

Bolt connections shall have double nuts with cable connectionssoldered to the first nut. All cable terminals shall be crimped andsoldered to the cable. Solid copper bars shall be used to prevent oilsiphoning on wires.

15.2.6. Instruments

Rectifiers shall have readily accessible direct current voltmeters andexternal shunt type ammeters.

In areas with a high frequency of lightning strikes, knife switches willbe added to the meter circuits allowing meter isolation when not in use.

15.2.7. Ratings

Unless otherwise specified, all units shall be rated for maximum 45(113 F) ambient temperature.

15.2.8. Circuit diagram and parts list

Circuit diagrams parts lists shall be furnished with each rectifier byvendor.

15.2.9. Protective devices

Manually operated circuit breakers or magnetic starters with properlysized instantaneous and time delay trips shall be used for controllingthe rectifiers.

15.2.10. Transformer oil

Nondetergent, noninhibited transformer oil is required for rectifieruse because transformer oil detergents and inhibitors attack Selenium,the major component in most cathodic protection rectifiers.

15.2.11. Special auxiliary futures

Remotely located units require a DC system failure detector consistingof a visible light driven by a DC magnetic relay.

Special input frequencies, silverplates connections, lightningprotection, constant current transformation, etc. shall be specifiedwhere required by design.


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15.2.12. Foundations for base mounted units

Shall conform to the requirements of civil design specifications.

15.3. Impressed Current Ground Beds

15.3.1. Anode material

Unless otherwise specified, impressed current anodes shall becomposed of graphite rods sized to meet the current requirements ofthe installation. The rods shall be fully impregnated with wax or othersuitable binding material. Alternate anode materials, used only inspecial problem areas, are junk steel, high silicon cast iron and leadsilver. Except in rare cases where construction conditions prohibit,each anode shall be encased with well-compacted soft coal orcalcinated petroleum coke breeze screened to proper particle sizerequirements.

15.3.2. Cable and wiring

Cable from the rectifier unit to ground bed shunt junctions and to theprotected structure shall be sized to carry the systems total currentwithout undue voltage drop.

Generally #1/0 or #1/0 single conductor, stranded copper cable willsuffice. Insulation should be a material such as high molecular weightpolyethylene, which will withstand long-term soil burial withoutdeterioration. Smaller cable or more durable insulation may bespecified as determined by current requirements and environmentalconditions of the specific project.

On all anodes, special care shall be taken with anode to cable

juncture. This flexure area is subject to damage and is a known causeof many past ground bed failures. Rigid inspection enforcement ismandatory for this sensitive anode region.

15.3.3. Shunts and shunt boxes

Current measuring shunts Each anode and all protective currentconnecting cables require current measurement methods. Generallycalibrated shunts are the simplest method for such measurements.These voltage drop shunts shall be housed in adequately sizedsurface cabinets if possible. Where below ground shunt installationsare required, they shall be fully insulated from the soil.


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15.3.4. Cable splicing materials

Underground splicing of cathodic protection cables should be avoidedif possible.Under no circumstances should below ground splices of positivecables in deep anode ground beds be allowed. Above ground splicesare permissible. Where splices are made, proper material should beused to ensure a long lasting, low resistance splice. Typical materials

are:

- Appropriately sized copper solder lug.- 50% tin 50% lead solder with noncorrosive flux- Pressure sleeve connectors

15.3.5. Insulation

Buried negative cable splices shall be insulated with one of thefollowing materials:

- Hot applied asphalt or coal tar pipeline enamel poured into a properly

formed and sized container over primed surface.- Individualized epoxy insulating compound kits.- Two component cold cured epoxy.

15.3.6. Other

Canvas based phenolic such as Miscast, Bakelite or Synthane typeinsulating board material shall be used for special insulating problemssuch as positioning bolted connections in above ground junctionboxes.

15.3.6.1. Casing

Adequately sized polyethylene, PVC or glass reinforced plastic pipeshall be installed as casing in the abovecoke breeze segment of deepanode ground beds.

15.3.6.2. Concrete

Material requirements for concrete and its contents are given in relatedJob Specification, N00-FSTC-SP-0005.


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All gaskets shall be Maloney Type E (Full Face) or approvedequivalent. Type F (Inside Bolt Circle) may be required where flangemisalignment occurs. All bolts shall have double insulation. In highlightning strike areas surge gap material may be inserted between thebolts insulating washers.

Gaskets for 20 in. flanges and above shall be faced with neoprene orhave pressure sealing inserts.

15.6.2. Pipeline insulating union

Insulating pipeline unions can be used if they meet pipeline hydraulicrequirement.In areas subject to high lightning strike (high resistance soil regions,etc.), arrestors shall be installed across the union.

15.7. Casing Insulators

Depending upon individual project conditions, insulating of the pipelinefrom casings at highway and railroad crossings shall use one of thefollowing techniques and materials:

15.7.1. Build-up abrasion pads

Pipelines coated with asphalt enamel, coal tar enamel and Somaticmaterials can be insulated from their casing sections with built upabrasion and support pads fabricated in the field with coating materialsused on the line.

15.7.2. Mechanical

Plastic or neoprene insulating devices shall be used for insulatingpipelines from support pads. The following material requirements apply

in their selection:

15.7.2.1. Pipe Sized Through 12inch

Glass reinforced epoxy or polyester molded insulators such asMaloney No. 57 or Plastic Products, Inc. nonconductive casinginsulator or equivalent shall be used.Nonreinforced material or other plastics should not be used becauseof undesirable cold flow characteristics.


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15.7.2.2. Pipe Sizes above 12inch

Skid type insulating devices are required to support weights involvedwith the large pipelines. Insulators shall be steel banded with insideand edges insulated and with skids made of either: (1) glass reinforcedepoxy or polyester such as Maloney Type PF or (2) canvas basedphenolic such as SP1 A8 and A12 or Maloney 63 and 59. Minimumwidth of insulator shall be 203 mm (8 min.) with the more durable 305

mm (12 in.) insulator being specified for larger diameter pipe asgoverned by weights involved. Paper based phenolic, nonreinforcedplastics, or plastics other than above are not acceptable because ofcold flow or moisture absorption tendencies. Equivalent insulationmaterial is acceptable.

15.7.3. Casing seals

Like casing insulators, casing seals may either be fabricated in thefield using the pipelines coating materials or by installing purchasedmechanical seals.Purchased seals shall be neoprene. Either the pull on or wrap around

seal will serve depending upon characteristics of the pipeline systeminvolved.

15.8. Galvanic Couples

Dissimilar metallic components assembled according tomanufacturers specifications shall be inspected, tested and evaluatedfor damaging galvanic couples prior to acceptance. Where corrosivegalvanic couples are found, remedial changes such as installation ofinsulating devices or replacement of dissimilar metallic parts orcompatible metals shall be carried out prior to accepting the itemsinvolved.


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Table C - LOCATION OF ELECTRICAL TEST POINTS FOR POTENTIAL MEASUREMENT

LOCATION TESTPOINTS

REMARKS

1.Coated pipeline, cased, at roads,railways, canals:Casings less than 45.7 m (150) inlength

Casing 45.7 m (150) and greater inlength

1Measurement of pipe to soil and casing tosoil potentials.

2Measurement of pipe to soil and casing tosoil potentials at each end of casing

2.Coated pipeline, greater than 762 m(2500) between casings

1Measurement of pipe to soil potential nearcenter

3.Long bare pipeline sections 1 kmintervals

Measurement of pipe to soil potential

4.Long bare pipeline section beingcathodically protected

0,5 kmintervals


5.Pipeline near foreign owned rectifierground bed

2Measurement of pipe to soil potentialwhere pipe enters and leaves anodic field

6.Pipeline opposite government owned

rectifier ground bed within 305 m (1000)of line

1


7.Joint interference at crossing of foreignline

1Requires prior approval of regulatoryagency and foreign company

8.Insulated flanges or couplings 2 One on each side9.Main line riser 1 Adjacent ground junction with riser10.Buried structure opposite galvanicanode battery

1Measurement of structure to soil potential

11.Dissimilar metal systems near groundbed

1

Measurement of buried structure to soilpotential on affected metal as galvanizedconduit, iron sewer lines, copper groundcables, steel anchors, etc.


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Table D - LOCATION OF ELECTRICAL TEST POINTS FOR CURRENT MEASUREMENT

LOCATION TEST POINTS REMARKS1. Rectifiers and galvanic anode batteries 1 Measurement of total current output

2.Ground bed connected to rectifier1

Measurement of individual ground

bed3. Power anode 1 Measurement of anode output4. Buried metallic structure

1Measurement of return current fromeach structure connected to negativeside of cathodic protection unit

5. Negative rectifier lead connected toburied structure

1Measurement of current magnitudeand direction flowing in the structure

6. Long coated pipeline sections Max 10 kmintervals

Measurement of cathodic protectioncurrent flow

7. Insulated flanges1

Measurement of possible currentflow

8. Pipelines operated by otherAt practical points

Measurement of current magnitudeand direction where ownership oroperational jurisdiction changes

9.Long inaccessible pipeline sections

2

Measurement of currents enteringand leaving sections such as majorwater crossings and congestedareas

10.Interfering and/or straying currentsAs required

Measurement of current as requiredfor specific instance

Documents

00 FELE SP 0024 Cathodic Protection