Updated information from PG&E regarding gas pipelines at Stanford
Officials from PG&E visited Stanford on Oct. 28 to provide further detail about the condition of natural gas pipelines that run through university property, as well as to provide further technical information for campus utilities managers.
In response to the greatest campus concern, PG&E clarified that there had been no detected external or internal corrosion to the Line 109 gas pipeline that runs along Junipero Serra Boulevard, and that the problems identified by the utility focused on the corrosion protection system for the 24-inch transmission pipeline. Four segments of Line 109, which PG&E said run along the boulevard from Stanford Avenue to 700 feet beyond Campus Drive, appeared last month on PG&E's list of 100 segments for priority maintenance.
"We found the information we received Thursday to be reassuring, in that there does not appear to be a corrosion issue with Line 109," said Larry Gibbs, associate vice provost for environmental health and safety. "PG&E has been working collaboratively with us, and we believe we have a good flow of back and forth information."
PG&E also said Thursday that Line 109 was originally installed through the campus in 1936, and that Line 132, which also runs adjacent to Junipero Serra, was originally installed in 1947. Both gas pipelines, which carry natural gas from Milpitas to San Francisco, have had segment updates several times since their original installation.
PG&E said the gas transmission lines were evaluated for internal corrosion in 2007, and none was found. The Junipero Serra segment of Line 109, however, did have its corrosion protection system enhanced, and upon further evaluation in 2009 the enhanced corrosion protection was working as planned, PG&E said.
The university met with PG&E on Sept. 24 and then sent the utility a list of detailed questions. PG&E sent a letter of response to the campus on Oct. 18 addressing some questions, and elaborated further in the conversation at the meeting on Oct. 28.
Gibbs said he expects conversations between Stanford and PG&E to continue. "We operate our own complex utility systems, so we will continue to have some detailed, technical follow-up questions," Gibbs said.
Given the heightened interest in gas pipelines and maintenance, the university has asked PG&E to provide advance notice whenever it will be conducting work on the transmission lines near the Stanford campus so that it can notify nearby campus residents.
The university has asked PG&E to elaborate on media reports that pipelines built before 1970 have unreliable welds. The utility's officials emphasized that a gas line with proper corrosion protection can safely transport gas, regardless of its installation date. They stated that lines 109 and 132 are still within their usable lifetime and that regular maintenance and monitoring is ongoing.
Campus utilities officials also have asked for more information regarding the location of PG&E's gas shutoff valves. PG&E will be holding a meeting with the Santa Clara County Fire Chiefs Association, including the Palo Alto Fire Department, on Nov. 11 to further discuss shutoff valves.
The university also received further information about the size and location of lower-pressure gas pipelines operated by PG&E throughout the campus, to ensure consistency in PG&E and university utilities maps. Moreover, PG&E discussed its plans to install several gas pressure regulator stations on its lines on or adjacent to the Stanford campus. Additionally, Stanford identified upcoming projects that may take place in the vicinity of the Junipero Serra transmission lines, including a PG&E project for addition of a new regulator and distribution service for the campus and the Santa Clara County traffic-calming project planned for Junipero Serra.
PG&E also provided the campus with an overview of its Pipeline 2020 Program, which is a long-term effort in its formative stages to "strengthen the natural gas transmission system and advance best industry practices over the coming decade."