Continued testing on PG&E's Line 132 is expected to cause traffic along Alma Street to be redirected for 10 days starting Jan. 18, City of Palo Alto Utilities Communications Manager Debra Katz said Tuesday morning (Jan. 17).
The work involves checking the outside casing surrounding the pipe for flaws. The 55-mile Line 132, which runs from Milpitas to South San Francisco, is the one involved in the San Bruno explosion and fire. The California Public Utilities Commission required PG&E to use hydrostatic (water pressure) testing to find leaks in the pipeline after the explosion.
Between September and November 2011, PG&E performed the tests on sections of the Line 132 pipe, which runs through Palo Alto. The pipe has been fully tested and was returned to full service in December, the city noted on its pipeline update page.
Related story: PG&E repairs leak in Palo Alto pipeline (Nov. 11, 2011)
The surrounding casing inspection would not cause impacts to service or any odors, Katz said. The main effect will be on commuters traveling southbound on Alma from Jan. 18 through Jan. 28. The work will be done between Alma and the Caltrain railroad tracks, just before the intersection with Oregon Expressway, Katz said.
PG&E will be working Mondays through Fridays from 9 a.m. to 4.p.m. and Saturdays from 9 a.m. to 6 p.m., Katz said.
"The 'effect' in terms of lane closures will only be in the immediate vicinity of the one location -- Alma just south of the Oregon Expressway. How far back that may slow traffic is unknown and will, of course, vary by time of day," she stated in a post on PaloAltoOnline's Town Square.
Standard "warning" orange traffic signs indicating lane closures and "men working" signs will be posted, she said.
The work will not be done in front of the Alma Garden Apartments, as was the case when PG&E did hydrostatic testing, Katz said.
Katz said commuters should consider taking alternate routes.
PG&E has three main transmission pipelines that traverse Palo Alto -- Lines 101, 109 and 132. Line 132 is the only one of the three pipelines required to be tested in PG&E's current hydrostatic testing project, the city noted.
Line 109 runs along Middlefield Road from Mountain View but then turns up East Charleston/Arastradero Road, continuing north along Foothill Expressway. It has had about two thirds of its length replaced in recent years and is believed to have been hydrostatically tested already but paper record verification of that is still underway, according to PG&E.
Originally installed portions of this pipeline -- running along Charleston between Alma and Middlefield -- are scheduled for replacement sometime between 2012 and 2014. That schedule is currently being prepared, according to PG&E.
Line 101 runs roughly parallel to Highway 101. All of the Palo Alto portions of this pipeline have been replaced since the requirement for hydrostatic testing was in place and there are validated records of passing this test, according to PG&E.
PG&E intends to install a permanent "in the pipeline inspection device" launching station on East Bayshore Road that will allow future regular, ongoing inspections. Construction of this device could start as early as summer of 2012.
The city's website, www.cityofpaloalto.org, is kept updated with information on PG&E activity in Palo Alto, Katz said.