Palo Alto Weekly

Spectrum - September 30, 2011

On Deadline: Why is there a "Shut-Off-Valve Gap" between the U.S. and Canada?

NTSB report loaded with details of PG&E's shortcomings in oversight of its gas pipelines

by Jay Thorwaldson

It's ironic that in the 1950s PG&E was installing a defective gas-transmission line beneath San Bruno while Canada was installing a system of large pipelines with automated shut-off valves.

In the wake of the deadly San Bruno Line 132 explosion a year ago such valves would be mandated by several proposed new state laws — which still seem decades late.

A scathing new report issued this week by the National Transportation and Safety Board (NTSB) lays the blame for the deadly San Bruno inferno directly on "a systemic problem" within PG&E and regulatory agencies that have ignored earlier signs of lax safety. (The executive summary is at www.ntsb.gov/investigations/summary/PAR1101.html .)

Palo Alto city officials are watching developments closely, both because Palo Alto owns its own utilities — gas, electrical, sewer — and because testing is underway of a main pipeline that runs through town.

The city is awaiting final results of a water-pressure test of the main PG&E transmission line running through town. The initial segment, known as T-29, was tested Sept. 10 — a year and a day after the San Bruno inferno. The test took about a week of preparation that included digging holes, venting the line of gas and filling it with water, then closing everything up. The tested segment comes up Middlefield Road from Mountain View, then zigzags left to Alma Street.

Preliminary results indicate the line passed the 10-hour test, which entailed pressurizing the line to higher-than-normal pressure, according to Debra Katz, communications manager for Palo Alto utilities.

A second segment, T-30, which runs up Page Mill Road from Alma before cutting right into Menlo Park, is scheduled to be tested Oct. 15. The test was postponed because PG&E shifted the testing to a Menlo Park segment.

So Palo Altans appear to be safe, so far.

But the San Bruno blast provides both a fiery backdrop and an incentive to correct a deficiency the NTSB believes never should have existed.

Its report cites "inadequate quality assurance and quality control in 1956 during its Line 132 relocation project." PG&E installed "a substandard and poorly welded pipe section with a visible seam weld flaw that, over time grew to a critical size."

The line ruptured during "a pressure increase stemming from poorly planned electrical work at the Milpitas Terminal," the report says.

A second huge factor was an "inadequate pipeline integrity management program, which failed to detect and repair or remove the defective pipe section."

If that weren't enough, both the California Public Utilities Commission (PUC) and the U.S. Department of Transportation allowed exemptions from required pressure testing of existing pipelines, "which likely would have detected the installation defects."

And the PUC failed to detect the inadequacies of PG&E's "pipeline integrity" management program.

Finally, the NTSB gets to the nub: "Contributing to the severity of the accident were the lack of either automatic shutoff valves or remote control valves on the line and PG&E's flawed emergency response procedures and delay in isolating the rupture." During the 95 horrific minutes eight people died, many more were burned, 38 houses destroyed and 70 damaged.

Now, nearly six decades later, the irony of the missing automated valves seems apparent to legislators and officials at all levels.

Such valves automatically close if there is a sudden drop in pressure, indicating a major rupture or leak in the system — shutting down both ends of the failed line.

This type of valve, given some probable technological advances, would be required under several new bills in the state Legislature.

The Canadian valves are big, covering lines from 20 to 48 inches in diameter, with a hydraulic, pressure-based closure mechanism that requires no outside power source. Crews locate the problem, fix it and reopen the valves. (Descriptions of two such valves are at: www2.emersonprocess.com and www.atiactuators.com)

One engineer who works on the Canadian system said that although shutoff time would be shortened it depends on how fast pressure drops. In any case it would be faster than finding someone with keys to a manual valve, he said.

Shawn Mindus, who now works for a pharmaceutical firm based in Palo Alto, was an engineer in a Canadian system for five years. He told the Weekly he was astounded when he learned that the San Bruno line had to be manually closed off. He acknowledged that nearly all the Canadian large transmission lines are outside urban areas, but said shutoff valves, including those near urban areas, tend to be just several kilometers apart.

The NTSB had strong praise for San Bruno firefighters and other local public-safety personnel who responded within two or three minutes — other local responders showed up quickly.

But San Bruno is not the first failure of PG&E and regulators, and that PG&E still had no clear emergency-response plan or chain of command as of last year, the NTSB report says.

"Poor quality control and inadequate emergency response" were factors in the 2008 pipeline explosion in Rancho Cordova. Not only was an inadequate pipe installed but PG&E initially dispatched an unqualified person to the site, causing additional delay in getting a trained person there.

"Some of these deficiencies were also factors in the 1981 PG&E gas pipeline leak in San Francisco, which involved inaccurate record-keeping, the dispatch of first responders who were not trained or equipped to close valves, and unacceptable delays in shutting down the pipeline," the report says.

The NTSB investigation "concluded that PG&E's multiple, recurring deficiencies are evidence of a systemic problem."

PG&E says it is now moving quickly on multiple fronts to improve safety and oversight — and the PUC has begun proceedings to assure that happens. In early August PG&E named a new CEO and president, Anthony F. Earley, Jr. It has an extensive "frequently asked questions" section on its website, www.pg&e.com.

Current-President Chris Johns on Aug. 30 said the NTSB findings are "an important milestone" and the company "will take to heart" the findings to see that "such a terrible accident never happens again."

Former Weekly Editor Jay Thorwaldson can be e-mailed at jthorwaldson@paweekly.com and jaythor@well.com.

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