Source: Los Angeles Times, June 4, 2015
Posted on: http://envfpn.advisen.com
Corrosion had eaten away at nearly half of the metal wall of a pipeline that ruptured and spilled up to 101,000 gallons of crude oil along the Santa Barbara County coast last month, federal regulators said Wednesday.
The 10.6-mile pipeline had “extensive” external corrosion and the thickness of the pipe’s wall where it broke had degraded to an estimated 1/16 of an inch, according to preliminary findings released by the Pipeline and Hazardous Materials Administration.
Investigators found a six-inch “opening” along the bottom of the pipe where it broke on May 19. About 21,000 gallons from the spill went down a culvert and into the Pacific Ocean near Refugio State Beach.
Preliminary results from an internal inspection conducted two weeks before the rupture by Plains All-American Pipeline, which owns the pipeline, revealed metal loss of around 45% of the wall’s thickness in the area of the break, according to regulators.
Three other areas of the pipeline had experienced deep metal loss ranging between 54% and 74% of its original wall thickness, regulators said.
The area where the pipe broke had been repaired at least three times since 2012, according to the regulators’ findings.
Regulators ordered Plains All-American Pipeline to inspect another pipeline with similar corrosion issues that transports crude oil 128 miles from Santa Barbara County to Kern County.
The failed pipeline transports crude oil from Exxon Mobil’s storage tanks in Las Flores to a pump station in Gaviota and operates at up to 120 degrees Fahrenheit.
Richard B. Kuprewicz, a pipeline incident investigator with 40 years’ experience who is not involved in the federal probe, said he was not surprised that the line was corroded, given the temperatures in the pipe.
“Heated pipe is a bona fide risk threat, every operator knows that,” he said. “It’s a heated line with a history of past concerns — no surprise. It’s going to be an expensive fix.”
Kuprewicz said external corrosion is common, and can be managed by applying special coatings to the pipe and by adhering to a rigorous inspection and monitoring program.
“A 45% loss is not in itself a problem,” he said. “But a prudent operator has to stay ahead of this kind of thing. It’s called pipeline integrity management.”