Question

The San Bruno pipeline explosion (the case in our first lecture) occurred at 6:11 pm PDT on September 9, 2010, in San Bruno, California, a suburb of San Francisco, when a 30-inch (76 cm) diameter steel natural gas pipeline owned by Pacific Gas & Electric (PG&E) exploded into flames in the Crestmoor residential neighborhood 2 mi (3.2 km) west of San Francisco International Airport near Skyline Boulevard and San Bruno Avenue.

“The (investigation) report concluded that poor pipeline welds went undetected because of a lack of inspections by the company and inadequate monitoring by state and federal regulators. The utility also lacked a workable emergency response plan that board members said could have helped to prevent the devastation in the city of San Bruno.”

"This represents a failure of the entire system — a system of checks and balances that should have prevented this disaster," said Robert L. Sumwalt, an NTSB board member. "The seam weld may have been the technical reason, but this was an organizational accident."

“Even though PG&E is a Local Distribution Company (LDC), a gas utility - and not primarily a midstream company - there were plenty of lessons to be learned by everyone, upstream, downstream, and all points in between. The investigation showed a myriad of events that led up to the catastrophe but a huge discovery was that PG&E and subsequently, many LDC's in the US, could not locate adequate records of their pipelines. Some did not even have emergency plans in place. Important records that were missing included type of pipe, when and where the line was installed, welding inspection reports, coating reports, in-line inspection histories, operating pressure changes, and more. All this data is critical to correctly operating and maintaining a steel pipeline. It was learned that some LDC's could not even locate some of their pipeline assets!”

Based on the above description and your knowledge about “Pipeline Integrity Management”, please :

1) identify the problems in the PG&E’s pipeline management from above description;

2) give your recommendations (at least FOUR items) to the PG&E to prevent similar failures happen again in the future.

Answer 1

Problems of pg&e management:

1. Lack of reports of previous checkup and installation data.

2. Lack of having manufacturing data like type of weld, type of coating etc

3. Lack of proper maintenance and inline checkup.

4. Lack of having emergency controlling system.

5. Improper monitoring of pipeline and having lack of proper technology to monitor.

6. Not keeping track of outside pressure and temperature variation is also a failure.

Recommendations to prevent failure

1. Install SCADA( supervisory control and data acquisition) system.

2. Pigging of pipeline at least once a month to clean inner surface of the pipe.

3. Emergency control system and alarm linked with SCADA.

4. Magnetic particle testing of welding done on pipeline, before installation.

5. Installation of solenoid check valve in between every 300 m of pipline, having a pilot line linked to SCADA.