Stanford officials in discussions with PG&E to address concerns about gas transmission pipelines near campus
Stanford utilities personnel continue to communicate with PG&E on issues related to gas lines near Stanford and also are attempting to determine when inspections of these lines will be finished.
The recent gas pipeline explosion in San Bruno has understandably increased concerns over the status of natural gas transmission lines near Stanford University. On Monday, Stanford was notified by PG&E that a section of pipeline that runs along Junipero Serra Boulevard is on the PG&E "Top 100" list. The list is one of PG&E's protective maintenance and risk management planning tools used by engineers to focus resources and plan for enhanced monitoring or future work on gas transmission pipelines. Stanford utilities personnel continue to communicate with PG&E on issues related to gas lines near Stanford and also are attempting to determine when inspections of these lines will be finished, as PG&E is under a directive to complete inspection of all its pipelines by Oct. 12. In the following Q&A, Larry Gibbs, associate vice provost for Environmental Health and Safety, provides further information.
What is the specific problem with the pipeline under Junipero Serra Boulevard?
According to the PG&E list, portions of a 22-inch diameter pipeline under Junipero Serra have been found to be at risk for corrosion. There are four small segments, for a total of one mile of pipeline, that appear as numbers 56, 60, 61 and 62 on PG&E's list of 100. PG&E reports that the cathodic (electrical current) system that protects the pipeline against corrosion was "adjusted for better protection" and that "an analysis of the system in 2009 showed a marked improvement." PG&E says it will continue to monitor the segment "but no further action is contemplated at this time."
What action is the campus taking with PG&E?
The university's utilities experts have been working closely with PG&E since the San Bruno explosion, and have been in close communication with PG&E officials to seek more information about the status of gas lines near the campus. We have requested a meeting with PG&E officials, which PG&E has agreed to arrange in the next day or two, to follow up on the information we received Monday. We will be working to better understand what work has been done on the pipeline, what will be done to ensure continued integrity of the pipeline, and why the segments remain on PG&E's "Top 100" list if no further action is contemplated at this time.
What does the campus advise nearby residents to do?
University officials plan to keep the community informed and to share the information we have received from PG&E.
Where exactly are the gas pipelines located around Stanford?
There are two PG&E gas transmission lines that run along Junipero Serra Boulevard near the campus. These gas lines run from Milpitas through Palo Alto, along Junipero Serra Boulevard and on into San Mateo County. One of the lines runs from Palo Alto up Arastradero Road where it turns north on Junipero Serra Boulevard and the other runs up Page Mill Road and turns north along Junipero Serra Boulevard. The location of gas transmission lines along Junipero Serra Boulevard is quite clearly marked along the sides of the roadway. There are two types of surface signs, both demarcating the location of the underground gas lines. One is a diagonal sign about eight feet above the ground with orange and white striping. Between these signs, you will observe bright orange stake-like signs periodically spaced along the path of the gas pipeline, clearly marked with a warning of Gas Pipeline below. Most of those markings are within five to 10 feet or so of the edge of Junipero Serra roadway, which is part of Santa Clara County land. All of these gas transmission lines are located at least four feet below the soil surface. Maps of all the gas transmission lines operated by PG&E can be located at: http://www.pge.com/myhome/customerservice/response/pipelineplanning/.
These gas transmission pipes are identified by PG&E as Line 132 on the foothill side of Junipero Serra, a 24-inch diameter steel pipe; and Line 109, which is a 22-inch diameter pipe on the campus side of the road. A smaller 10-inch pipe also runs from the 109 pipeline along Campus Drive West to the Cardinal Cogeneration facility on the Stanford Campus, which provides electricity and steam for the campus. Line 109 is the one specifically identified by PG&E on Monday with some segments on the "Top 100" list for continued monitoring.
Are these gas pipelines unsafe for continued use?
Being on this "Top 100" list doesn't mean the line is unsafe for continued use. The segments identified near the Stanford residential area are on the list for follow-up priority monitoring, which has been occurring regularly. When pipe corrosion evaluation is the primary criterion for inclusion on the list, PG&E indicates that it monitors both electronically and physically, physically checking every two months at such segments in its high-pressure natural gas transmission system.
Are there high-pressure lines throughout campus?
Except for the one 10-inch line that feeds the cogeneration facility, all buildings and residences on campus with natural gas are fed by low-pressure gas distribution systems through small pipes. Due to the lower pressure, these pipes don't carry the same risk of pipe leakage or rupture, but gas can still leak through old connections or open valves, such as when the burner on a gas stove is left in the on position. This is why everyone should always report any smell of natural gas, whether in a lab building, or in your residence on campus. For any gas odor on campus, you can dial (650)723-2281 and report the gas odor location for immediate follow-up by Buildings & Grounds Maintenance staff. If during non-business hours, you can also call 911 to report a natural gas odor and emergency personnel will respond.
Should the campus community be concerned about gas pipeline safety?
Typically, the greatest risk for gas lines is from underground excavation that can damage a pipe during such digging. Any project that requires excavation undergoes what is termed an Underground Service Alert (USA) review, a mandatory process to identify any possible underground services or utility lines that might be encountered during an excavation. Design engineers and Stanford project managers who work on such projects are well versed in these issues and the sensitivity of any excavation taking place near gas lines. All such work near any gas transmission lines is closely coordinated with PG&E officials.
If anyone has further questions, please contact the campus Office of Environmental Health and Safety at (650) 723-0448.