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Aging Infrastructure Management and Challenges. Sue Fleck Vice President Pipeline Safety Trust “ Getting to Zero ’ Conference 2011. Contents. Background – National Grid Distribution Industry Metrics Recent Safety Performance Preventative Measures Fitness for Service
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Aging Infrastructure Management and Challenges Sue Fleck Vice President Pipeline Safety Trust “Getting to Zero’ Conference 2011
Contents • Background – National Grid • Distribution Industry Metrics • Recent Safety Performance • Preventative Measures • Fitness for Service • Material Considerations • Main Inventory by Material • One New England Example
US Gas Distribution Operating in: MA, NH, NY & RI Approx: 3.5 mil Customers 2.6 mil Service Lines 1,800 Stations 36k mi Distribution Main 29k mi Service Piping 500 mi Transmission Main NH MA NY RI
2.1 million miles of main 65 million services Age from brand new to over 100 years old Size from ½” to over 36” in diameter Materials: Cast Iron, Bare Steel, Cathodically Protected Steel, Plastics Distribution Industry Metrics
Distribution Safety Performance Leaks & Incidents Leaks Significant Incidents Serious Incidents Note: Leak and mileage data for 2010 is not yet available. 2010 Incidents are per 10,000 miles using 2009 miles.
All 2010 + 2011 Natural Gas Distribution Incidents by Causes
Decade of Installation for Facilities All 2010 + 2011 Gas Distribution Incidents
Materials Involved in Natural Gas Distribution Incidents 2010+2011
Preventative Measures • Actions distribution companies are taking to avoid incidents • Perform leakage surveys • Perform corrosion surveys • Patrol pipelines • Inspect facilities • Perform pipeline location marking • Monitor operations metrics • Determine fitness for service
Fitness for Service • Defined as the ability of different types of facilities or components to satisfactorily perform; delivering gas safely and reliably • Track and trend condition and performance • Age • Material • Maintenance records i.e., leaks/mile, /service… • Operating records i.e., pressures, flows… • Determine whether to repair, rehabilitate or replace facilities based on a risk assessment
Plastic – material of choice for services and mains in distribution system operating at lower pressures Non-corrosive Subject to excavation damage Cast iron – installed until the 60’s for mains and large diameter services Corrosion resistant Susceptible to cracking Joints susceptible to leakage Steel – material of choice for mains and services at high pressures and mains of large diameter Can be protected from corrosion Resistant to excavation damage Expensive to install Material Considerations
One New England State Example • Instituted a Safety and Reliability Program to replace infrastructure demonstrated to be leak prone • Approximately 3,000 miles of pipe, half leak prone • Includes all replacement programs • Programs must be pre-approved by commission • Level of spending must be pre-approved by commission • Eliminates regulatory lag • Annual reconciliation filing required • Ramped up pipe replacement program mileage from single digits to approximately 50 miles per year