In what one of the utilities has designated as a "new era" in natural gas transmission pipeline safety and maintenance programs, California's two major utility pipeline operators for thousands of miles of intrastate, high-pressure pipelines told state regulators Monday that there are still gaps in some of their pipeline recordkeeping in high-population areas such as the San Bruno neighborhood that was devastated by a pipeline rupture last September.
Pacific Gas and Electric Co. (PG&E) submitted more information to support its contention that gaps in its pipeline recordkeeping on pressure testing of major transmission lines did not contribute to the Sept. 9 blast and fire that killed eight people in San Bruno. The San Francisco-based combination utility is under increasing pressure and is facing fines from the California Public Utilities Commission (CPUC) related to its inability so far to satisfy the state panel's mandates for more complete pipeline information coming out of an ongoing federal probe related to the root cause of the pipeline failure.
The investigations have drawn the Sempra Energy utilities' pipeline system into the regulatory fray, and they made a filing last Friday that acknowledges that for up to 28% of their transmission pipelines in high consequence areas (HCA) there are no clear records of pressure tests that have been completed to support the operating pressures now in use on those lines. While claiming that the pipelines are being operated safely, the filing by Southern California Gas Co. (SoCalGas) and San Diego Gas and Electric Co. (SDG&E) said that in the wake of San Bruno the U.S. pipeline industry has entered a new era.
However, a Los Angeles-based Sempra utilities spokesperson said the amount of pipelines actually lacking verification could be considerably less because a very conservative approach was taken in applying the federal criteria of what is "traceable, verifiable and complete" in terms of pipeline records. "[News reports] also have wrongly indicated that somehow we should have strength test records for all of our pipelines, but strength testing has not always been required," the spokesperson said.
"[We] recognize that natural gas utilities nationwide are entering a new era with respect to natural gas pipeline safety in light of the San Bruno pipeline rupture, and our commitment to safety must take that new era into account," the Sempra utilities' said in a response to the CPUC. In their report, SoCalGas-SDG&E said 73% (1,033 miles) of SoCalGas' 1,416 miles of HCA pipelines and 69% (142 miles) of SDG&E's HCA pipelines have documentation of hydrostatic or equivalent pressure tests. Collectively, for a remaining nearly 450 miles of transmission pipelines, they still have not located documentation of such tests.
Similar to PG&E, Sempra's utilities have indicated they do not have the test verification for the maximum allowable pipeline pressures (MAOP) used on these pipeline segments, and thus they will consider operating them at reduced pressures while they continue their records search.
"Nothing in our records review process revealed any significant concerns with the currently established MAOPs for pipelines [designated as Category 4 Criteria Miles]," SoCalGas-SDG&E told the CPUC, but given the so-called new era is pipeline safety, they are considering several options.
Those possible options include continuing the ongoing pipeline records search; exploring whether in some cases operating pressures can be reduced; conducting pipeline strength tests using water or other appropriate means; validating line strength through inline inspection technologies; and considering replacing some segments of pipe.
Sempra noted that for 207 miles of the so-called Category 4 Criteria Miles of pipeline the pipe has been already assessed and its integrity upheld through the use of the in-line technology known as "smart pigs."
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