1. Guidelines for Inspection of In-plant Buried Process Piping Authors: Tony Kakpovbia Ph.D. Randy Vander Voort

2. 2  API 570 Framework,  Inspection Planning,  Frequency and Extent of Inspections,  Methods of Inspection,  Excavation,  Repairs and Records,  Summary and Benefits. Scope of Presentation

3. 3 API 570 Framework  Section 9 of API 570 recognizes two distinctions regarding buried pipe:  Significant External Deterioration,  Inaccessibility.

4. 4 API 570 Framework  Subsections of Section 9 are:  Types and Methods of Inspection.  Direct and indirect monitoring (limited reference).  Frequency and Extent of Inspection.  Repairs to Buried Piping System.  Records.

5. 5 Inspection Planning  Process Hazard Analysis (PHA) issues:  Analysis by one of:  Hazards & Operability Analysis (HAZOP),  Failure Mode & Effects Analysis (FMEA),  Fault Tree Analysis.  MSDS review and regular safety training.  Complete, review, approve and regularly update Management of Change (MOC) documentation.

6. 6 Inspection Planning  Complete periodic qualitative evaluation of risk on the likelihood versus consequences grid basis.  Complete quantitative risk assessment, if possible.

7. 7 Inspection Planning Analysis of Generated Inspection Data  Pre-installation (baseline) risk assessment:  Complete PHA, personnel training,  Review plant operations & engineering data,  Establish and approve MOC plan,  Estimate potential operating life,  Establish inspection intervals.

8. 8 Inspection Planning Analysis of Generated Inspection Data  Operating:  Annual inspections data review,  CP System performance review,  Review pipe internal inspection data,  Complete RBI evaluation – minimally qualitative, preferably including quantitative,  Update MOC plan,  Determine remaining life,  Update inspection interval.

9. 9 Inspection Planning Inspection Methods  Direct Techniques:  Measurement of metal loss or corrosion rate,  Intrusive,  Non-intrusive.

10. 10 Inspection Planning Inspection Methods  Indirect Techniques:  Measurement of parameters that may influence or are influenced by metal loss.  Surface technologies,  On-line,  Off-line.

11. 11 Leak Detection  Visual:  Surface contour,  Discoloration of soil,  Softening of the surface,  Pooling, bubbling, poor drainage,  Odor.

12. 12 Leak Detection  Thermography:  Identify leaks that travel to surface.  Tracer Detection:  Tracer Chemicals – add to process,  Helium Gas – offline.

13. 13 Excavations  Hand Excavation:  Within a few inches.  Mechanical Excavation:  Back hoe,  Gradall.

14. 14 Excavations  Hydrovac Excavation:  “Day lighting”,  Nondestructive,  Minimal soil removal.  Frozen ground,  No source of ignition.  Hydrovac excavation is not foolproof.

15. 15 Excavations

16. 16 Inspection Methods - Surface  Indirect: Non-Intrusive:  Visual Surveillance,  Leak Testing,  Close Interval Potential Survey,  Soil Resistivity – high resistance soils require lower CP current,  Cathodic Protection (CP) Monitoring.

17. 17 Inspection Methods - Surface  Direct: Intrusive:  Intelligent pigging,  MFL, UT, RFT,  Remote Visual Inspection.  Guided Wave Ultrasonic Testing.

18. 18 Guided Wave Ultrasonic  What is Guided Wave Ultrasonic Testing?  A sonic technique using torsional and longitudinal waves.  Sensitive to ID and OD wall losses.  Up to 48” diameter.

19. 19 Guided Wave Ultrasonic

20. 20 Guided Wave Ultrasonic

21. 21 Guided Wave Ultrasonic Results  A typical weld is completely symmetric and shows up as only a black curve.  A typical corrosion patch is non- symmetric and is identified by the presence of a red curve.

22. 22 Guided Wave Ultrasonic

23. 23 Guided Wave Ultrasonics  Advantages:  Full circumferential data,  Non-intrusive, on-line and off-line,  Up to 4,000 feet per day,  Use on lined, coated, insulated or buried pipe,  Portable,  Repeatable results.

24. 24 Guided Wave Ultrasonics  Disadvantages:  Buried pipe dampens signal (30 meters).  Concrete lining,  Coatings,  Wrapping.  Placement on pipe critical.  Pipe configuration critical.  Not quantitative data; sorting tool only.  Follow-up with direct inspection required.

25. 25 Inspection Methods - Below Grade  Direct - Non-Intrusive:  Pipe Coating Holding Survey,  Ultrasonic Corrosion Survey,  Radiography – profile shots,  MT/PT,  Surface Profile Mapping, Pitting,  Manual,  Computerized (Laser Pro).

26. 26 Inspection Methods - Below Grade  Direct - Intrusive:  Pipe Sample/cut out collection,  Intelligent Pigging,  MFL, UT, RFT.  Video Camera.

27. 27 Intelligent Pigging  Magnetic flux leakage.  Ultrasonic.  Remote Field Eddy Current.

28. 28 Video Camera

29. 29  Repairs:  As per B31.3,  As per Section 8.2 of API 570.  Records:  Permanent and progressive,  Inspection results, CR, repair history. Repairs and Records to Buried Pipe

30. 30 Summary  Buried pipe needs an assessment and inspection program like any process plant piping.  Don’t fall into “out of sight, out of mind”.  Must address with both internal and external metal loss.  Indirect techniques help with risk ranking/inspection planning.

31. 31 Summary  Cathodic Protection has many benefits:  Minimizing soil side corrosion,  Thinner walled pipe, less C.A.,  Increased inspection intervals.  GWUT is emerging as a powerful tool for sorting purposes.

32. 32 Summary  Intelligent pigging is becoming more process plant friendly.  Excavation should be a last resort; controls for safety and coating damage of major importance.

33. 33 Acknowledgements  Ken Izer, Chevron, California.  Tim Ryan, GE Inspection Technologies, Alberta.  Dave Russell, Russell Technologies, Alberta.  Larry Martin, formerly of Acuren, Alberta.