Guidelines for Inspection of Inplant Buried Process Piping

1
Guidelines for Inspection of In-plant Buried
Process Piping

• Authors
• Tony Kakpovbia Ph.D.
• Randy Vander Voort

2
Scope of Presentation

• API 570 Framework,
• Inspection Planning,
• Frequency and Extent of Inspections,
• Methods of Inspection,
• Excavation,
• Repairs and Records,
• Summary and Benefits.

3
API 570 Framework

• Section 9 of API 570 recognizes two distinctions
  regarding buried pipe
• Significant External Deterioration,
• Inaccessibility.

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.

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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.

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Inspection Planning

• Complete periodic qualitative evaluation of risk
  on the likelihood versus consequences grid basis.
• Complete quantitative risk assessment, if
  possible.

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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.

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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
Inspection Planning

• Inspection Methods
• Direct Techniques
• Measurement of metal loss or corrosion rate,
• Intrusive,
• Non-intrusive.

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Inspection Planning

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

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Leak Detection

• Visual
• Surface contour,
• Discoloration of soil,
• Softening of the surface,
• Pooling, bubbling, poor drainage,
• Odor.

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Leak Detection

• Thermography
• Identify leaks that travel to surface.
• Tracer Detection
• Tracer Chemicals add to process,
• Helium Gas offline.

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Excavations

• Hand Excavation
• Within a few inches.
• Mechanical Excavation
• Back hoe,
• Gradall.

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Excavations

• Hydrovac Excavation
• Day lighting,
• Nondestructive,
• Minimal soil removal.
• Frozen ground,
• No source of ignition.
• Hydrovac excavation is not foolproof.

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Excavations
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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.

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Inspection Methods - Surface

• Direct Intrusive
• Intelligent pigging,
• MFL, UT, RFT,
• Remote Visual Inspection.
• Guided Wave Ultrasonic Testing.

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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.

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Guided Wave Ultrasonic
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Guided Wave Ultrasonic
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Guided Wave Ultrasonic

• Results

• A typical corrosion patch is non-symmetric and is
  identified by the presence of a red curve.

• A typical weld is completely symmetric and shows
  up as only a black curve.

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Guided Wave Ultrasonic
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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.

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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.

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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).

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Inspection Methods - Below Grade

• Direct - Intrusive
• Pipe Sample/cut out collection,
• Intelligent Pigging,
• MFL, UT, RFT.
• Video Camera.

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Intelligent Pigging

• Magnetic flux leakage.
• Ultrasonic.
• Remote Field Eddy Current.

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Video Camera
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Repairs and Records to Buried Pipe

• Repairs
• As per B31.3,
• As per Section 8.2 of API 570.
• Records
• Permanent and progressive,
• Inspection results, CR, repair history.

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Summary

• Buried pipe needs an assessment and inspection
  program like any process plant piping.
• Dont 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.

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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.

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Summary

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

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Acknowledgements

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