Corrosion Control and Monitoring

1. Corrosion Control and Monitoring ABC Company ABC Chemical Complex Engineering Specification

2. Corrosion Control & Monitoring • SCOPE • 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.

3. Corrosion Control &Monitoring • GENERAL • 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.

4. 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

5. 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

6. Corrosion Control & Monitoring • REFERENCES • 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

7. Corrosion Control & Monitoring • PERSONNEL REQUIREMENTS • 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.

8. Corrosion Control & Monitoring • PERSONNEL REQUIREMENTS (Cont..) • 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.

9. Corrosion Control & Monitoring • DESIGN REQUIREMENTS, EXTERNAL • 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.

10. 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.

11. 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.

12. 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.

13. 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.

14. 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.

15. 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.

16. 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.

17. 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.

18. 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.

19. Corrosion Control & Monitoring • DESIGN REQUIREMENTS, INTERNAL • 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.

20. 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.

21. 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.

22. Corrosion Control & Monitoring • DESIGN REQUIREMENTS, ABOVE GROUND EXTERNAL • 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.

23. Corrosion Control & Monitoring • INSTALLATION • 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.

24. 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.

25. 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.

26. 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.

27. 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.

28. 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.

29. Corrosion Control & Monitoring • OPERATIONS • 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.

30. Corrosion Control & Monitoring • MAINTENANCE • 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.

31. 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