Plastic gas pipes to be replaced in California after explosions
16 March 2012
California state regulators have said large sections of Pacific Gas & Electric’s gas distribution network will need replacing because of the high risk of failure of a particular type of plastic pipe used extensively throughout the network. Pipes made by DuPont before 1973 from a plastic called Aldyl-A were responsible for explosions in Cupertino and Sacramento in 2011.
The Cupertino condo after the gas pipe blast
Pacific Gas and Electric Co. (PG&E), whose lines were involved in both blasts, said late last year that it would remove more than 1,200 miles of the pipe from its system. When the operation has been fully costed, PG&E will go to the California Public Utilities Commission to ask for a rate increase to cover the cost.
The pipes are used to supply natural gas directly into homes and businesses, and are smaller than main transmission lines such as the PG&E pipe that exploded in San Bruno in 2010, killing eight people.
The August 31 blast in Cupertino destroyed a condominium, and the Roseville explosion less than a month later resulted in the shutdown of a major intersection for more than 12 hours. No one was hurt in either incident.
A task force that the Public Utilities Commission formed after the San Bruno disaster said that Aldyl-A pipe was among 17 major hazards connected with the state's natural-gas delivery system that require immediate action.
It said in a statement that it would investigate whether other utilities in California besides PG&E were taking steps to identify and deal with the risk from the plastic pipe, which federal officials first recommended be removed in 2002.
In 1998, after a similar type of plastic pipe cracked in Waterloo, Iowa, causing an explosion that destroyed a bar and killed six people, the National Transportation Safety Board recommended utilities and state regulators better monitor plastic piping from that era and replace it when they find it to be a risk.
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