PG&E Created Own Pipeline Safety Rule
Tuesday, March 15, 2011 @ 02:03 PM gHale
To avoid time-consuming and costly inspections of natural-gas transmission pipelines, Pacific Gas and Electric Co. (PG&E) created its own safety standard federal officials said was an “incorrect” interpretation of government safety regulations.
PG&E decided in 2008 it would test for weld problems on its older lines only if pressure on the pipes had spiked to a level 10 percent above a standard defined under federal rules, according to a report published in the San Francisco Chronicle. They cited an internal company document instructing its operators how to manage the gas-transmission system.
Under those federal regulations, however, such inspections should occur after any incident in which an older, potentially faulty pipeline’s pressure level exceeds the standard by even the slightest amount.
Officials with the U.S. Pipeline and Hazardous Materials Safety Administration said PG&E’s 10 percent add-on was “incorrect.” However, they said they would need more documentation to determine whether the company had “misapplied” federal regulations.
The pressure standard is based on the highest level at which a line was operated in the five years before a pipeline owner identified it as subject to a 2002 federal gas-pipeline inspection law. If the pressure goes over that level, the owner must inspect for any damage done to welds that hold a pipe’s seams together, federal regulations said.
The San Bruno pipeline that exploded Sept. 9, killing eight people and destroying 38 homes, failed at a faulty seam weld, federal metallurgists found. PG&E had twice exceeded the line’s maximum pressure cap, but never conducted an inspection for flawed seam welds.
There are two types of inspections one is to shut down a line for days and pump it full of high-pressure water, or run a device through a line with sophisticated sensors.
PG&E said the San Bruno pipeline could not accommodate the sensor devices, and the company has long avoided water-pressure tests that can cost from $125,000 to $500,000 per mile and shut down a line for several days.
Pressure on the San Bruno line exceeded the maximum allowed under law when PG&E intentionally surged gas levels in 2003 and 2008. When it inspected the pipeline in 2009, the company used a method that detects corrosion, but not for finding bad welds.
PG&E spelled out its inspection policy for older lines such as San Bruno in a March 2008 internal document prepared by Gene Muse, an official in the company’s risk management program.
It said PG&E wouldn’t conduct tests that can find weak seam welds unless a pipeline’s pressure had exceeded the pressure cap — the five-year maximum level — by 10 percent.
The goal was “to keep from continuously losing operating pressure on pipelines that have a potential long seam manufacturing threat,” said the document.
The 10 percent level, the document explained, came from a separate federal regulation that allows pipeline pressures to temporarily exceed legal caps by as much as 10 percent under extraordinary circumstances.
For example, if an emergency pushes pressure above maximum allowable levels, the federal rule gives operators leeway to account for gas building up in lines before relief valves activate and reduce the flow.
A spokesman for PG&E did not explain why the company believed it could graft the 10 percent exception to the federally imposed pressure cap. Instead, he noted the company had halted intentional pressure surges on gas-transmission lines after the San Bruno disaster.
“We are currently reviewing all of our risk management policies and procedures,” spokesman Joe Molica said. “Safety is our highest responsibility, and we are working hard to restore public confidence in the safety and integrity of our gas pipeline operations.”