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Stress Corrosion Cracking Overview & Introduction

Stress Corrosion Cracking Overview & Introduction. David Johnson December 2, 2003. SCC History. Not a recent phenomenon Not exclusive to pipelines Not confined to underground environment Not geographically limited Ammonia cracking of cartridge brass Chloride cracking of stainless steel.

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Stress Corrosion Cracking Overview & Introduction

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  1. Stress Corrosion CrackingOverview & Introduction David Johnson December 2, 2003

  2. SCC History • Not a recent phenomenon • Not exclusive to pipelines • Not confined to underground environment • Not geographically limited • Ammonia cracking of cartridge brass • Chloride cracking of stainless steel

  3. Requirements for SCC

  4. SCC Characteristics

  5. SCC Characteristics

  6. SCC near Seam Weld

  7. Metallography of SCC

  8. Summary of Incident Causes

  9. Summary of Significance • Natural gas transmission(1985-2002) • 15 of 1415 total reported incidents • Liquid transmission (PPTS) • 5 of 472 in database • NEB (Canada) (1992-2002) • 3 of 23 • None since 1995 • Overall - about 1% of incidents

  10. Why Today’s Interest? • Other, higher significance threats also being addressed

  11. Other Threats (B31.8S) • External Corrosion • Internal Corrosion • Manufacturing Defects • Welding & Fabrication Defects • Equipment Failure • Third Party / Mechanical Damage • Incorrect Operations • Weather & Outside Force

  12. External & Internal Corrosion • CP systems • Gas quality standards and monitoring • Relatively mature ILI capability • Correlated to hydro-test capability • Rapidly maturing DA capabilities

  13. Manufacturing & Construction • Specifications - materials & construction • Advances in materials technology • Mill inspections • Construction inspections • Proof testing

  14. Third Party Damage • Dig Safety • Common Ground Alliance • One Call enforcement • Enhanced public awareness

  15. Incorrect Operation • Operator Qualification programs • Qualification of controllers • OQ-2 • B31Q

  16. Equipment Failure • Gaskets, Seals, Valves, Pumps, etc. • Generally not pipe • Generally confined • Specifications, testing, maintenance

  17. Weather & Outside Forces • Design & Construction • Forecasting • Monitoring • Better understanding of material responses

  18. Why Today’s Interest? • Other, higher significance threats also being addressed • Less apparent understanding • Small, but widespread, occurrence • Methods of addressing not as mature • Inspection, characterization, assessment, management

  19. Today’s Workshop • Share available information • Understand application of current management techniques • Update on R&D • Future Needs • Technology development • Regulatory approach

  20. Managing SCC • Operators have found & managed SCC • Tools as prescribed in PLSIA of 2002 • In-Line Inspection • Hydrostatic Testing • Direct Assessment • Other • All have specific capabilities & limitations • Gas - Liquid Pipeline Differences

  21. Major Challenges • Finding SCC • Shallow cracks initially • May not be visible to unaided eye • Gas - Liquid technology differences • Service disruptions • Water disposal • Assessing what is found • Mitigation and Management

  22. Research & Development • Multi-faceted approach • Environmental factors • Surface preparation & coatings • CP system operation • Operational factors • Material behavior • Detection & sizing

  23. Regulatory Response • Determining reasonable response • Setting investigation protocols • Communication needs

  24. Upcoming Panels • Operator Experience with Finding and Managing SCC • TransCanada • Enbridge • Kinder Morgan • Duke • Williams • Colonial

  25. Upcoming Panels • R & D • What’s been done • Current work • Future needs • PRCI • ILIA • NACE

  26. Upcoming Panels • Regulators • Concerns & Needs • NEB • EUB • MNOPS • USDOT-OPS

  27. Contacts Dave.L.Johnson@Enron.com KLeewis@PRCI.org

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