When a natural gas pipeline ruptured in California in 2010, the response from an industry that prioritises safety was immediate. And even eight years later, regulatory focus continues on one of the accident’s root causes: Insufficient material properties knowledge.
As investigators discovered, the section where the rupture occurred had been cobbled together from various pipe segments of unknown specifications. There was no material property information for the segments, although there was little question they weren’t made of the seamless, high-grade steel the operator’s as-built drawings indicated.
To help prevent a similar tragedy, the industry set out to address the need for traceable, verifiable and complete pipeline records. This started with the Integrity Verification Process (IVP) and has resulted in additional material properties requirements for gas transmission lines in High Consequence Areas, which are expected to be released by the Pipeline and Hazardous Materials and Safety Administration (PHMSA) in March 2019. Among the new requirements will be the verification of pipe materials.
In Europe, pipeline condition assessment activities have also ramped up, especially when it comes to ageing pipelines. Some companies, including a major Dutch natural gas operator, have increased the standards for equipment that will be permanently installed on their lines, such as hot tap fittings.
Pipelines constructed in the last 10 to 20 years should have traceable, verifiable and complete records, including hydrostatic test reports, MAOP validation and mill-test reports for specific pipe lots. But what about ageing assets, specifically those installed prior to 1970? According to PHMSA, 59% of US gas transmission pipelines fall into that category, meaning there’s significant potential for missing records. In fact, in 2016, natural gas operators in the US reported that 7.242 km (4500 miles) of pipe in High Consequence Areas and Class 3 and 4 locations had inadequate records to confirm maximum allowable operating pressure.
The issue is equally urgent outside of the US. For example, based on CONservation of Clean Air and Water in Europe (CONCAWE) data, 47% of the assets they cover were installed prior to 1970. And while it does not explicitly contain specific data on percentage of pipelines installed prior to 1970, the European Gas Pipeline Incident Data Group’s (EGIG) ninth report published in February 2015 does address the influence of the age of pipelines on their failure frequencies.
Kehl will describe an innovative method for overcoming missing or incomplete pipeline data in ageing assets. By incorporating the TDW Pipe Joint Classification process, this approach recreates important pipe material records. In addition, it improves confidence that the operator has applied the appropriate level of risk to specific pipe joints and segments.
About the presenter
Rich Kehl holds degrees in Engineering Sciences from Dartmouth College, Mechanical Engineering from Stanford University and Aeronautics and Astronautics from the Massachusetts Institute of Technology. He joined TDW as Product Director – Hot Tapping & Plugging in 2017. Kehl leads the strategic direction of the product and service lines, facilitating a team composed of product management, sales, engineering, manufacturing, and service operations. Prior to TDW, Kehl managed global product portfolios of GE’s power generation equipment, power plant configuration, and air quality components.
