Stress Corrosion Cracking Workshop December 2, 2003

1. Stress Corrosion Cracking WorkshopDecember 2, 2003 Steve Rapp Duke Energy Gas Transmission

2. Stress Corrosion Cracking Workshop Overview of Company Pipeline Facilities Overview of the Company Pipeline Re-validation Program and SCC Operational History Method for Identifying Locations with Potential SCC SCC Management Methods

4. A Snapshot of a Hydrostatic Retest Program • Total mileage tested: 1343 miles (1986 – Present) • Total number of test sections: 63 • Very high applied hydrostatic test pressures: Typically greater than 100% SMYS • Average age of pipeline: 35 years in service • Approximate cost: $50MM

6. No Action Required No Action Required SCC Susceptible – Prioritize Accordingly SCC Hydrostatic Retest SCC Susceptible Site – Prioritize Accordingly Minimum Criteria to Qualify as SCC Test SCC Susceptible Site Method for Identifying Potential SCC Locations Are B31.8S SCC Requisite Conditions Satisfied ? SCC Hydro Test? Yes No Page 2 Yes SCC Hydro Test Failure? No Yes No Hydro test date within past 20 years? Yes No Page 2 Page 1 of 2

7. Crack Indications Found? Define re-inspection interval Crack Severity Scale Sleeve Cutout Grind Coat & Backfill Coat & Backfill Develop a Prioritization Scale of SCC Locations Bellhole Inspections SCC Hydrotest SCC Hydrotest Define Reinspection Interval Remediation Methods How: Bellhole Inspection Program: 1) Pressure Reduction 2) Coating Removal Method 3) Coating Removal Length Where: Site Selection 1) Terrain (slope) 2) Drainage 3) CP 4) Secondary Loading 5) SME MT Inspection/ Documentation Procedure Apply SME Knowledge When: 1) Routine Maintenance 2) Deliberate Dig for SCC Safe Grinding Practice Inputs:1) Geography (Soil Type)2) Age3) Coating Type4) Stress Level5) Distance from Discharge 6) MT Inspection Results 7) SME Knowledge a) Operating Temp b) Pressure Cycles c) Coating Condition SCC Mitigation Methods Company SOP No Yes Page 2 of 2