On September 9, 2010, a little more than two years ago, a San Bruno, California neighborhood was rocked by a huge explosion caused by a rupture in a 30 inch natural gas pipeline. That explosion woke up the natural gas pipeline industry and its regulators and made the public slightly more aware of the dangers associated with piping flammable, explosive vapors at high pressures in underground pipes that are often located under heavily populated areas.
Platts Energy Week recently interviewed Don Santa, the president of the Interstate Natural Gas Association of America (INGA) and Bizunesh Scott. a former official from the Department of Transportation, which regulates pipeline safety.
You can learn more about the event, the analysis of its causes, and the prescriptions for attempting to prevent future accidents by reading the Pacific Gas and Electric Company Natural Gas Transmission Pipeline Rupture and Fire San Bruno, California
September 9, 2010 – Accident Report NTSB/PAR-11/01 PB2011-916501.
Here is a quote from the Executive Summary of the report:
The rupture produced a crater about 72 feet long by 26 feet wide. The section of pipe that ruptured, which was about 28 feet long and weighed about 3,000 pounds, was found 100 feet south of the crater. The Pacific Gas and Electric Company estimated that 47.6 million standard cubic feet of natural gas was released. The released natural gas ignited, resulting in a fire that destroyed 38 homes and damaged 70. Eight people were killed, many were injured, and many more were evacuated from the area.
Here is an even more thought provoking quote from the accident synopsis.
The rupture occurred at 6:11 p.m.; almost immediately, the escaping gas from the ruptured pipe ignited and created an inferno. The first 911 call was received within seconds. Officers from the San Bruno Police Department arrived on scene about 6:12 p.m. Firefighters at the San Bruno Fire Department heard and saw the explosion from their station, which was about 300 yards from the rupture site. Firefighters were on scene about 6:13 p.m. More than 900 emergency responders from the city of San Bruno and surrounding jurisdictions executed a coordinated emergency response, which included defensive operations, search and evacuation,
and medical operations. Once the flow of natural gas was interrupted, firefighting operations continued for 2 days. Hence, the emergency response by the city of San Bruno was prompt and appropriate.
However, PG&E took 95 minutes to stop the flow of gas and to isolate the rupture site—a response time that was excessively long and contributed to the extent and severity of property damage and increased the life-threatening risks to the residents and emergency responders. The National Transportation Safety Board found that PG&E lacks a detailed and comprehensive procedure for responding to large-scale emergencies such as a transmission pipeline break, including a defined command structure that clearly assigns a single point of leadership and allocates specific duties to supervisory control and data acquisition staff and other involved employees. PG&E’s supervisory control and data acquisition system limitations caused delays in pinpointing the location of the break. The use of either automatic shutoff valves or remote control valves would have reduced the amount of time taken to stop the flow of gas.
How bad might the accident have been if there was not a fire station just a few hundred yards away?