Mechanical Damage F I N A L R E P O R T submitted to U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration Office of Pipeline Safety Integrity Management Program Under Delivery Order DTRS56-02-D-70036 (Technical Task Order 16) submitted by Michael Baker Jr., Inc. in association with APRIL 2009 Table of Contents Table of Contents 1 Introduction ........................................................................................................................................... 1 1.1 Overview ..................................................................................................................................... 1 1.2 Mechanical Damage in Perspective ............................................................................................. 1 2 Background ........................................................................................................................................... 5 2.1 Problem Statement ....................................................................................................................... 5 2.2 Current Regulatory and Industry Practice Perspectives .............................................................. 5 2.3 Project Scope Overview .............................................................................................................. 6 3 Literature Review .................................................................................................................................. 7 3.1 Literature Search and Database ................................................................................................... 7 3.2 Recommended References .......................................................................................................... 7 3.3 Database Description ................................................................................................................... 9 3.4 References ................................................................................................................................. 10 4 Understanding Mechanical Damage in Pipelines ............................................................................... 11 4.1 Defining Mechanical Damage ................................................................................................... 11 4.1.1 Dents ..................................................................................................................................... 13 4.1.2 Gouges. .................................................................................................................................. 13 4.1.3 Combined Defects ................................................................................................................. 13 4.2 Mechanical Damage Features and Characteristics .................................................................... 14 4.2.1 Elastic Spring-Back and Re-Rounding .................................................................................. 15 4.2.2 Stress/Strain Fields [Hopkins and Leis (2003)] .................................................................... 15 4.2.3 Reduction of Toughness and Ductility Due to Strain ............................................................ 15 4.3 Geometry and Characterization of Damage .............................................................................. 16 4.4 Repair Conditions and Failure Modes ....................................................................................... 19 4.4.1 Immediate Repair Conditions ................................................................................................ 20 4.4.2 Delayed (or Scheduled) Repair Conditions (ANSI/ASME B31.8S, 2004) ........................... 20 4.4.3 Growth of Cracking from Mechanical Damage .................................................................... 21 4.4.4 Leak versus Rupture .............................................................................................................. 21 4.5 Failure Statistics ........................................................................................................................ 21 4.5.1 U.S. Industry Experience (PHMSA, 2008) ........................................................................... 22 4.5.2 Experience Outside the United States ................................................................................... 24 4.5.3 Comparative Statistics ........................................................................................................... 27 4.6 Summary .................................................................................................................................... 28 4.7 References ................................................................................................................................. 29 5 Prevention ........................................................................................................................................... 30 5.1 Overview ................................................................................................................................... 30 5.1.1 Mechanical Contact ............................................................................................................... 30 5.1.2 Handling Damage .................................................................................................................. 31 5.1.3 Rock Dents ............................................................................................................................ 31 5.1.4 Human Error .......................................................................................................................... 32 5.2 Existing Prevention Methods and Technologies ....................................................................... 32 5.2.1 Planning and Land Use ......................................................................................................... 32 5.2.2 Damage-Resistant Coatings .................................................................................................. 33 5.2.3 Lowering and Support ........................................................................................................... 37 5.2.4 Backfill .................................................................................................................................. 37 5.2.5 Public Education and Awareness Campaigns ....................................................................... 39 5.2.6 Marking and Signage ............................................................................................................ 40 5.2.7 Right-of-Way Maintenance ................................................................................................... 40 Mechanical Damage Study April 2009 Page i Table of Contents 5.2.8 Mapping ................................................................................................................................ 41 5.2.9 Surveillance ........................................................................................................................... 42 5.2.10 One-Call System ............................................................................................................... 43 5.2.10.1 Participation .................................................................................................................. 45 5.2.10.2 Enforcement of Notification ......................................................................................... 45 5.2.10.3 Accessibility ................................................................................................................. 45 5.2.10.4 Positional Accuracy ...................................................................................................... 46 5.2.10.5 Processing Time ........................................................................................................... 46 5.2.10.6 Quality Assurance ........................................................................................................ 46 5.2.10.7 Pilot Programs .............................................................................................................. 46 5.2.10.8 Virginia Pilot Project .................................................................................................... 47 5.2.10.9 Effectiveness ................................................................................................................. 49 5.2.10.10 Locating and Marking .............................................................................................. 49 5.2.11 Excavation Procedures ...................................................................................................... 50 5.2.11.1 Tolerance Zones ........................................................................................................... 50 5.2.11.2 Selective Daylighting ................................................................................................... 51 5.2.11.3 Equipment Operating Procedures ................................................................................. 51 5.2.11.4 Site Supervision ............................................................................................................ 51 5.2.11.5 Effectiveness ................................................................................................................. 52 5.2.11.6 Other Prevention Methods ...........................................................................................