Stress Corrosion Cracking Overview

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 Todays 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 Todays 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
Todays Workshop

• Share available information
• Understand application of current management
  techniques
• Update on RD
• 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
• Whats 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_at_Enron.com KLeewis_at_PRCI.org