Fire Threat Fuels Gas Valve Debate

On the morning of the Northridge earthquake, 122,886 customers of Southern California Gas Co. shut off their gas because they feared damage could cause an explosion or fire.

Later, when workers went to restore service, they found that only 15,021 of the cases, or about 12%, actually involved leaks or other damage that merited a shut-off.

And of the 51 structural fires after the Jan. 17, 1994, quake that were related to natural gas mishaps, nearly half were caused by movement of unstrapped water heaters that ruptured connections.

One lesson for earthquake preparedness is clear--water heaters should be secured and connected with flexible lines--but the issue of whether to install automatic gas shut-off mechanisms in quake-vulnerable Los Angeles continues to simmer.

Gas-fueled fires were a major cause of death after last year’s quake in Kobe, Japan.

In Southern California, a quake disaster scenario prepared by Stanford University researchers and the quake mitigation firm of Risk Management Solutions assumes that there is a significant threat of fire if a major quake strikes during high winds.

According to the scenario, if a magnitude 7 quake were to strike on the Newport-Inglewood fault, which slices through some of the Los Angeles urban area, fire losses could range from almost nothing to $70 billion, depending on whether a Santa Ana wind was blowing.

The state Public Utilities Commission and the Los Angeles Fire Department are pressing, though not too hard, to expand gas shut-off capabilities.

The state Seismic Safety Commission, in its report on the Northridge earthquake, recommended last year that “the use of automatic shut-off valves, as appropriate” be encouraged.

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The Southern California Gas Co. takes another view. It contends that the risk of fire after a major quake does not justify the cost of shut-off valves. The gas company supports a voluntary customer decision to install shut-off devices, and has test marketed what it considers the best such product to areas containing 300,000 of its customers.

The gas company once calculated that if all buildings within its service area had been equipped with gas shut-off valves at the time of the 1987 Whittier Narrows earthquake, 3 million customers would have lost service, and restoration would have taken 60 to 90 days.

A recent survey for the gas company indicated that most customers’ patience for living without natural gas would be exhausted within a week.

“A long period without natural gas for heat, particularly during the cold winter months, could impair the health of infants, the elderly and infirm, among others,” said a gas company report.

“Extended loss of natural gas service would also cause the loss of an important energy source for cooking unrefrigerated food or for sterilizing water.”

The push for shut-off gained impetus from teams of California emergency officials who visited Kobe after the 1995 earthquake there.

They told of more than five hours of delays during which fires killed hundreds of people as Osaka Gas Co. executives agonized over requests that they shut off gas to whole neighborhoods where major lines had ruptured.

Finally, with the approval of the board of directors of the company, gas was shut off for 860,000 customers.

The Kobe quake occurred Jan. 17, on the one-year anniversary of the Northridge quake, and service was not restored completely until April 11.

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The Kobe delays led to a recommendation by the city of Los Angeles’ Emergency Operations Organization that the Fire Department study “the adequacy of existing plans and procedures” to shut off gas flow “to specific sections of the city if deemed necessary for public safety.”

Even before the Kobe quake, the Public Utilities Commission accepted an offer by Southern California Gas Co. to improve its shut-off ability by reducing “isolation areas”--where the gas could be shut off at once--from 20,000 households or businesses to 10,000.

Donna Sanchez, the gas company’s emergency service manager, said the delays in Kobe would not occur in Los Angeles because district managers here have the authority to order shut-offs in their areas, if necessary, without consulting higher officials.

Since last Oct. 1, the gas company has been test-marketing a $349 home shut-off valve manufactured by Safe T Quake Corp. of Van Nuys.

It attaches to the gas meter and cuts off the flow of gas when ground shaking exceeds 20% of the force of gravity.

With taxes and required permit fees for installation, the cost was more than $400. A larger valve for businesses exceeded $1,500. Only about 1,000 of the devices have been sold.

Los Angeles has an ordinance that requires automatic shut-off valves only in new homes.