PG&E broke ground last week on a project in Foster City that will replace aging plastic gas pipes, according to city officials.
Approximately 15,000 feet of pipeline are expected to be replaced by 2014. The project’s first phase began in the neighborhood surrounding Edgewater Park and will replace 6,000 feet of distribution lines constructed from DuPont’s Aldyl-A plastic. In total, Foster City has about 17 miles of this kind of pipeline.
Although the material meets current regulatory standards, in the past few years there have been at least two separate incidents in California where pipes constructed from the plastic ruptured.
In 2011, a Cupertino gas distribution line built with Aldyl-A exploded and caused property damage. No injuries were reported. Less than a month later in Roseville, another burst pipe caused property damage but no injuries.
But despite past explosions and a 1982 warning from DuPont, the plastic pipes comply with existing standards, said spokesman Christopher Chow of the California Public Utilities Commission.
Aldyl-A plastic pipes are typically used for gas distribution lines, in contrast to the ruptured transmission lines responsible for the 2010 fatal PG&E explosion in San Bruno.
“Plastic pipelines operate at much lower pressures and stresses than steel transmission pipelines, and as a result leakage of gas, and not ruptures, are the primary concern for such materials,” Chow said.
But, Chow said, utility companies replace the plastic pipes to reduce risk in their overall distribution systems.
“Our top priority is safety,” said Jason King, a spokesman for PG&E. “We’ve embarked on an aggressive schedule to modernize our system.”
Foster City officials are aware of the potential problem with the plastic pipes.
“They’ve found in some areas this type of plastic pipeline has become brittle,” said Public Works Director Brad Underwood. Underwood said the city is supportive of PG&E’s effort to replace the potentially faulty pipes.
In addition to replacing the gas distribution pipelines, PG&E also plans to add smaller pipelines running parallel to the new ones. King said the smaller pipes will be used in the future for electricity reliability upgrades.
There will likely be temporary disruptions to gas service while PG&E connects the new distribution lines. The utility said it will contact individual customers about specific disruptions, King said. Phase 1 of the four-phase project begins today and will take eight to 10 weeks, Foster City officials said.