Q&A: PG&E Begins Pipeline 109 Replacement June 22

Mountain View residents can expect a little bit of inconvenience while Pacific Gas & Electric replaces portions of pipeline 109 starting June 22.

Part of its multi-year program to improve the safety of its natural gas system, the project will bring heavy equipment, lane closures on W. Middlefield Road between Terra Bella and Sierra Vista and on Terra Bella Avenue, and also sidewalk closure on the north side of Middlefield, according to a document given to businesses on the project route.

Residents and businesses in the area can also expect noise during the hours of 7 a.m. to 5 p.m. from Monday to Friday and 8 a.m. to 5 p.m on Saturdays. In the case of gas releases, the utility said it would notify affected customers.

Mountain View Patch had attempted to get information to residents earlier—since April 23—before the open house held on Thursday, April 26 from 5:30 p.m. to 7:30 p.m. at . Not until this Wednesday was any received. The following were emailed responses to questions sought by Patch sent by a company spokesperson.

Mountain View Patch: Why the replacement?

PG&E: Within the City of Mountain View we are both replacing pipeline and hydrostatically/strength testing a section of pipeline. Approximately 1.2 miles of Line 109 is being replaced and approximately 1.4 miles of Line 109 is being strength tested in 2012. The replacement work involves older, 22-inch and 34-inch diameter pipeline that is not “piggable”.  Further, much of this pipeline has not been previously strength tested. The strength testing involves 24-inch diameter pipeline that has not been previously strength tested.

Patch: When does the work begin?

PG&E: The pipeline replacement work consists of four project phases, all of which are scheduled to be completed in 2012.

• The first phase is complete and replaced approximately 0.3 miles of Line 109 along Manila Drive (note that less than 0.1 mile of it is in Mountain View).  The replacement started in April and was completed in June.

• The second replacement phase will replace Line 109 along W. Middlefield Road between Farley Street and Terra Bella Avenue.  The replacement is scheduled to begin the last week in June and be completed in mid-August.

• The third replacement phase will replace L109 along Terra Bella Avenue between W. Middlefield Road and N. Shoreline Blvd.  The replacement is scheduled to begin in August and be completed in October.

• The fourth replacement phase will replace Line 109 along Sierra Vista Avenue from a point half way between Rock Street and W. Middlefield Road and then along W. Middlefield Road from Sierra Vista Avenue to a point 0.1 miles east of N. Rengstorff Avenue. This replacement work is scheduled to begin in September and be completed in November.

• The location of the strength test for Line 109 is adjacent to Bayshore Expressway. It is being strength tested today, June 12, 2012. The test is expected to be complete at approximately 6:30 PM tonight with all work for the test being completed by the end of June.

Patch: Why has it been delayed?

PG&E: The first three replacement project phases and the strength test project were all scheduled to be completed in 2012, and the fourth replacement project in 2013. In order to minimize extended disruptions in the City of Mountain View, PG&E is accelerating the work between Rock Street and W. Middlefield to 2012. PG&E has been working to coordinate the projects with the City, the community and PG&E’s other replacement and strength testing projects on the Peninsula. Replacement and strength testing project schedules often require adjustment as design, permitting and routing issues are defined, which has been the case with the Line 109 projects in Mountain View.

Patch: How long will it take?

PG&E: The construction of the four 2012 replacement phases will take approximately three months each and the strength testing project will take five to six weeks. PG&E expects to be completed with all of the 2012 work in Mountain View by the end of November.

Patch: Will there be road closures?

PG&E: The first phase replacement work that was completed in June did involve a road closure. The construction work during the strength testing and the remaining three replacement phases will require lane closures, but not road closures.

Patch: What is the route of the replacement?

PG&E: See the response to Q1 above.

Patch: How long was the pipe being replaced in use?

PG&E: Approximately 6,440 feet of the total 7,466 feet of Line 109 pipeline being replaced in 2012 in the City of Mountain View was installed prior to 1970, with 5,619 feet installed in 1936. Note that the original installation of Line 109 was in 1936.

Patch: What is the procedure for this replacement?

PG&E: The majority of new pipeline is being installed by digging a trench along the same route as the existing pipeline, installing the new pipeline, strength pressure testing the new pipeline, and transferring the flow of gas from the old pipeline to the new pipeline. Once the new pipeline is in service, the old pipeline is cleaned and typically abandoned in place. At two locations, the pipeline will be “bored” or “pushed” through the ground for a distance of up to 500 feet in lieu of trenching.

Patch: Where else in Mountain View (and the region is PG&E) doing similar replacement work?

PG&E: PG&E is replacing a total of approximately 39 miles of pipeline in 2012.  This includes replacement work occurring along the Peninsula and in numerous locations throughout PG&E’s system.

Patch: How many customers live along the path of this pipeline?

Following is an approximate count of customers living immediately adjacent to the pipeline replacement sections:

• Phase 1: Approx. 10 residential structures
• Phase 2: Approx. 10 residential structures
• Phase 3: Approx. 25 residential structures
• Phase 4: Approx. 25 residential structures

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