Some PG&E pipeline questions answered

Last month, there was some discussion in the Chronicle and on our local Yahoo Groups about what lies beneath our feet. Emily Salgado in Senator Yee’s office picked up our email thread and has been working diligently on getting some answers from PG&E. Below is the email she sent to me, and that I hope she doesn’t mind me forwarding on to everyone concerned. This is a link to the pipeline map, which PG&E has de-color coded since last month.

Ms Salgado writes,

“Here is what I’ve been able to clarify from the CPUC.

1) The orange area on map indicates HCA’s under review. Is the line running at reduced pressure or no? If not, why?

Yes, the three transmission lines running into San Francisco are all being run at reduced pressure that is at least 20% below the maximum operating pressure. Immediately after the San Bruno explosion, the Executive Director of the CPUC directed PG&E to immediately reduce pressure on the remaining portions of the pipeline that ran through San Bruno (Line 132) by 20% of the operating pressure. The CPUC also ordered PG&E to reduce pressure on the other two transmission lines that run up the peninsula to San Francisco (Lines 101 and 109) because those lines have similar characteristics as Line 132.

The portion of the transmission line 109 that runs into the City of San Francisco was already operating at a pressure below 80% of its maximum allowable pressure so the pressure did not need to be reduced further. For a point of reference, the portions of the pipelines outside of San Francisco were reduced from 375-400 psi to 300 psi, where the pipeline in San Francisco was already operating at 200 to 250 psi.

2) Please clarify the green line, which according to the map means “pipelines in HCA’s w/ pressure test records…”
a. Does this mean the line in that area is safe, will not be under review, will be under review, will be reduced, or not?? Etc.

After the explosion in San Bruno it became apparent that PG&E did not have accurate records for its transmission pipeline system and could not fully justify the maximum allowable operating pressure on some pipelines. The CPUC ordered PG&E to do an extensive record search, and for pipelines where they have no records of the pipe ever being pressure tested to verify maximum operating pressure, PG&E will need to conduct the pressure test or replace the pipelines.

On June 9, 2011, the CPUC ordered all gas transmission operators to test or replace pipelines not previously tested. At the completion of the period, all of California natural gas transmission pipelines must, (1) be pressure tested, (2) have traceable, verifiable, and complete records, and (3) where warranted, be capable of accommodating in-line inspection devices.

The green color on the maps you reviewed do not indicate that the pipeline is “safe” or not safe. The line was an attempt by PG&E to show the segments where they have located the appropriated records. The non-green sections are still being reviewed to locate records or need to be pressure tested.

As mentioned, I am trying to ascertain when the CPUC mandated test or replace untested lines period ends or if there is an end date in mind. We know it has to be somewhat flexible but I will check in with the CPUC.”

A great many thanks to Senator Yee’s office and to Ms Salgado in particular in digging up this information and keeping us all in the loop.