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Corrosion Control and Monitoring. ABC Company ABC Chemical Complex Engineering Specification. Corrosion Control & Monitoring. SCOPE This Engineering Specification includes external and internal corrosion control and monitoring for DOT regulated pipelines.

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corrosion control and monitoring

Corrosion Control and Monitoring

ABC Company

ABC Chemical Complex

Engineering Specification

corrosion control monitoring
Corrosion Control & Monitoring
    • This Engineering Specification includes external and internal corrosion control and monitoring for DOT regulated pipelines.
    • Design, construction, construction inspection, construction acceptance, operation, and maintenance of DOT regulated pipelines are covered by this Engineering Specification.
corrosion control monitoring3
Corrosion Control &Monitoring
    • All DOT regulated ABC pipelines require protection from the environment.
    • Corrosive elements in the pipeline stream must be neutralized or the pipe material must be resistant to the stream.
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Corrosion Control & Monitoring
  • Minimum requirements for corrosion control:
    • External Corrosion Control
      • Buried DOT regulated pipelines will be coated and cathodically protected
    • Internal Corrosion Control
      • Known corrosion rate based on historical data
      • Corrosion rate from a national standard data base
      • Data collected from laboratory prototype testing
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Corrosion Control & Monitoring
  • Minimum requirements for corrosion control (Continued):
    • Above Ground External Corrosion Control
      • Coat with an approved system with resistance to the soil and internal fluid temperature
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Corrosion Control & Monitoring
    • NACE RP 0169-92
    • Surface Preparation:
      • NACE No. 1, SSPC-SP 5, White Metal Blast Cleaning
      • NACE No. 2, SSPC-SP 10, Near White Metal Blast
      • NACE No. 3, SSPC-SP6, Commercial Blast
      • NACE No. 4, SSPC-SP 7, Brush-Off Blast
corrosion control monitoring7
Corrosion Control & Monitoring
    • Engineering design will be performed by a Corrosion Engineer with training and experience in the proposed corrosion control system.
    • Coating, lining, and painting inspection will be performed by an inspector with appropriate training and experience.
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Corrosion Control & Monitoring
    • Cathodic protection installations will be inspected by an inspector with training and experience in cathodic protection inspection.
    • Internal corrosion monitoring installations will be inspected by an inspector with training and experience in internal corrosion monitoring inspection.
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Corrosion Control & Monitoring
    • Cathodic Protection Criteria
      • Buried Onshore Pipelines: Pipe-to-soil potential equal to or more negative than -0.85 volts referenced to copper-copper sulfate electrode and recorded immediately after current interruption (Instant-off potential).
      • Offshore Pipelines: Pipe-to-water potential equal to or more negative than -0.80 volts referenced to a silver-silver chloride electrode with “instant off” potential reading.
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Corrosion Control & Monitoring
  • Tank Bottoms: Steel-to-soil potential equal to or more negative than -0.85 volts with a copper-copper sulfate half cell and “instant off” potential.
  • Maximum pipeline potential: Equal to or less than -1.5 volts to a standard copper-copper sulfate half cell with the current temporarily interrupted.
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Corrosion Control & Monitoring
  • Coating Requirements
    • New buried pipe sections shall be coated with one of the following types:
      • Fusion bonded epoxy
      • Coal tar epoxy
      • Polyolefin tape
      • Prefabricated films
      • Other coating systems approved by Central Engineering
    • Surface preparation shall be in accordance with manufacturer’s recommendation and Appendix B.
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Corrosion Control & Monitoring
  • Methods Used for Cathodic Protection
    • Galvanic Anode Systems
      • Provide protection to the structure by the potential difference generated by the electrochemical reaction between the structure and the anode through a soil or water electrolyte.
      • Typically used in soil or water with resistivity less than 5000 ohm-cm.
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Corrosion Control & Monitoring
  • Methods Used For Cathodic Protection (Cont)
    • Impressed Current Systems
      • Uses external source of DC power, usually an AC trans-former with an AC to DC rectifier, to provide the driving voltage to the structure to be protected.
      • Potential difference between the anode and the structure creates current flow from the anode into the soil and onto the pipeline.
      • Used when the soil resistivity exceeds 5000 ohm-cm and/or more than 5 amperes of impressed current are required.
corrosion control monitoring14
Corrosion Control & Monitoring
  • Equipment
    • Galvanic Anode Systems
      • Anode: Magnesium onshore, Galvalum III offshore.
      • Junction box to connect leads from structure and anode.
    • Impressed Current Systems
      • DC transformer/rectifier (supplied as a unit).
      • Anode(s) with inert or low reactivity characteristics.
      • Terminal box with resistors to adjust current flow to each anode or anode string.
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Corrosion Control & Monitoring
  • Miscellaneous
    • Install lightning arrestors.
    • Provide electrical isolation: Insulating flanges or spools.
    • Minimize interference with bonding stations.
    • Install test stations to measure potentials.
    • Complete the following documentation:
      • Bonding and/or anode bed data sheet.
      • Bonding station data sheet.
      • Test station data sheet.
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Corrosion Control & Monitoring
  • Impact on Operating Equipment
    • Apply NEMA electrical-class safety requirements to all equipment associated with impressed current installations.
    • Install CP equipment in areas not requiring intrinsically safe design.
    • Locate anode beds to minimize effect on other structures and to minimize mechanical damage from foreign construction.
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Corrosion Control & Monitoring
  • Perform interference testing on all equipment that may be damaged by the new CP installation. Testing shall include, but is not limited to, the following situations:
    • Pipelines crossing within 5 feet.
    • Metal Structures within 5 feet of the pipeline.
    • Metal Structures within 200 feet of the anode bed.
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Corrosion Control & Monitoring
  • Impact on Operating Equipment
    • Design CP systems with capacity for current loss through interference bonds and future current loss due to coating deterioration.
    • Minimize casing installations for protection of the carrier pipe. Perform interference testing as shown in Company Corrosion Control & Monitoring Specification Appendix E. Provide bonding stations for each casing installation.
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Corrosion Control & Monitoring
    • Corrosive chemicals in the pipeline stream
      • May reduce stream (liquid or gas) quality or
      • Cause general thinning or pitting attack
      • Shall be handled by one of the following methods:
        • Neutralization or removal of the corrosive chemicals.
        • Select a pipe material which is resistant.
        • Coat the internal surfaces of the pipe.
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Corrosion Control & Monitoring
  • Design package will contain:
    • Provisions for upset/emergency conditions.
    • Recommended corrosion monitoring program.
    • Recommended corrosion monitoring equipment.
    • Installation of personnel safety devices and platforms required for safe performance of duties.
    • Pigging procedure when pigging facilities are included in the design package.
    • Compliance with regulations of local, state, and federal jurisdiction for pigging procedures.
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Corrosion Control & Monitoring
  • Documentation Requirements
    • Determine thickness measurement locations (TML’s) based on the most probable locations for corrosion or erosion-corrosion damage. Select TML’s with the assistance of the Corrosion Engineer.
    • Collect baseline thickness readings on all new installations.
    • Install corrosion monitoring equipment where the “worst case” corrosion attack is expected.
    • Provide corrosion monitoring data sheets.
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Corrosion Control & Monitoring
    • Coat with a coating system that is recom-mended for the environment.
    • Prepare surface in accordance with external-coating-system manufacturer’s recommendations. See Company Corrosion Control & Monitoring Specification Appendix B.
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Corrosion Control & Monitoring
    • Quality Control, External Systems
      • Coatings
        • Qualified Inspector presence - 100%.
        • Field applied coating systems - 100% inspection.
        • Shop applied coating systems - 100% inspection.
        • Coating repairs - 100% inspection.
        • Protect all stored coating materials at the construction site from weather, particularly directly sunlight and heat.
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Corrosion Control & Monitoring
  • Pad in the pipe trench
    • Inspect just prior to laying the pipe in the trench.
    • Remove all trash and construction debris.
  • Cables
    • Inspect upon receipt at job site to detect nicks and damage.
    • 100% inspection at the mill with proper mill cert..
    • Avoid damaging cable insulation during installation.
    • Splice cables aboveground in terminal boxes.
    • Use non-conductive conduits for cable installation.
    • Make cathode cable connections aboveground, if possible.
    • Repair buried connection in accordance with the original coating manufacturer’s recommendations.
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Corrosion Control & Monitoring
  • Transformer/Rectifier Systems
    • Install by a qualified electrician.
    • Test rectifier at maximum design load to assure the DC output meets the manufacturer’s specifications including the maximum AC ripple.
    • Calculate rectifier efficiency and record on the rectifier data sheet.
    • Verify the positive cable is attached to the anode bed and the negative cable is attached to the protected structure or pipe.
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Corrosion Control & Monitoring
  • Miscellaneous Considerations
    • Inspect cables in terminal boxes to assure correct labels.
    • Verify test stations, bonding stations, and associated hardware for cathodic protection service.
    • Contact owners/operators of foreign pipelines to enable testing before and after new cathodic protection project commissioning.
    • Record base readings on the new pipeline or structure prior to cathodic protection system energizing. Record potentials at all interference bonds and test stations.
    • Energize system in small current increments and record potentials with each increase until protection is achieved.
    • Check bonding stations for interference problems.
    • File all commissioning data in the original equipment file.
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Corrosion Control & Monitoring
  • Quality Control Requirements, Internal Surface
    • Inspect corrosion monitoring installations with the services of a qualified Corrosion Technician.
    • Take baseline data prior to pipeline commissioning.
    • Install lined pipelines per design.
    • Repair lining of field joints as recommended.
    • Install corrosion monitoring devices per design.
    • Complete electrical installations with qualified electricians.
    • Document commissioning information as a part of the original equipment file.
corrosion control monitoring28
Corrosion Control & Monitoring
  • Quality Control Requirements, Internal Surface
    • Delay work initiation pending review of design package by coating inspector.
    • Protect coating material from weather.
    • Prepare surface for coating per manufacturer’s recommendation immediately before coating installation.
    • Follow manufacturer’s recommendation for dew point and humidity.
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Corrosion Control & Monitoring
    • Perform cathodic protection surveys annually in accordance with Company CP procedure.
    • Monitor bonding and test stations annually.
    • Read and record rectifier output monthly with changes reported to the SR. Inspector for evaluation and action.
    • Correct deficiencies in a timely manner.
corrosion control monitoring30
Corrosion Control & Monitoring
    • Test rectifier stacks for proper performance annually.
    • Check anode bed resistance annually.
    • Check insulating flanges and spools annually.
    • Document all maintenance tests and add to the equipment file.
corrosion control monitoring appendices
Corrosion Control & MonitoringAppendices
  • A - Coating Reference Index
  • B - Surface Preparation
  • C - Sample Data Sheets
      • Rectifier Data Sheet
      • Anode Bed Data Sheet
      • Galvanic Anode Data Sheet
      • Potential Survey Data Sheet
  • Predesign Testing